Tetrahydrocannabinol otherwise known as THC is the chemical compound found in marijuana that produces its psychological effects. It works by stimulating the brain to release hormones such as dopamine, which is often referred to as ‘the happy hormone’. By releasing these hormones users start to feel the euphoric high that cannabis is best known for.

After the stresses of everyday life sometimes you need something a little stronger to relax with. That’s why our professional team of growers have compiled a list of 20 of the top high THC strains 2021 that money can buy. Users beware, these are not not for the faint hearted, they are the strongest weed strains known to man and should be reserved for seasoned smokers only!

What strain has the highest percentage of THC?

A common question that is often debated among friends and cannabis connoisseurs is ‘who has smoked the strongest weed?’ According to recent lab tests here are the top 5 highest THC strains tested:
  1. Gorilla Glue – 32% 
  2. THC Bomb – 32% 
  3. Bruce Banner – 31%
  4. Girl Scout Cookies – 28%
  5. Banana Kush – 27%


Gorilla Glue aka GG#4

Highest THC strains

Our list of the highest THC strains 2021 would not be complete without the world famous Gorilla Glue. Also known as GG#4 this knockout cannabis strain was aptly named after the famous super glue brand ‘Gorilla Glue’, because when the breeders harvested the plant, it was said that there was so much of the sticky resin that it stuck your scissors and fingers together like glue.

Gorilla Glue has won numerous awards since it was introduced in 2014, including 1st Place at the 2014 Cannabis Cup in LA and Michigan and more recently 1st Place at the 2018 Spannabis Cannabis Championship Cup.

Gorilla Glue is most well known for its super high potency and has been lab recorded at 32% THC multiple times, it is arguably the strongest cannabis strain in the world.

Training techniques: Gorilla Glue works well with most plant training techniques, although a trick to produce bigger yields and the highest THC levels is Supercropping. this is because the stress inflicted on the plant often causes the plant to increase nutrient uptake and increase trichome production. Gorilla Glue being a trichome rich plant works wonders with Supercropping. Read more on how to train your cannabis plants

Gorilla Glue #4 is a 50:50 hybrid, the plant will grow to around 200cm tall and have a dense foliage for dark green leaves spattered with white crystals. The buds grow thick and solid and will be heavily clustered spread over multiple main bud sites and the buds themselves will be a vibrant green colour with purple hues. The buds are so sticky and trichome rich that just simply breaking one open will fill a room with GG4’s famous musky, earthy, sweet aromas that will have you reaching for the rolling papers in an instant.

Gorilla Glue #4 is widely known as one of the strongest, if not the highest thc strain on the planet, with lab tested percentages up to 32%. The strain is not for the faint hearted and will give you one of the most intense highs you are likely to experience. When you smoke Gorilla Glue you will almost immediately be hit by its heavy full body buzz that will inevitably lead to couch lock. Gorilla Glue is a very intense high so is probably best suited to smoking in the evening when you can relax or simply if you have a day off work. Medicinally many users have reported that it is a great strain to combat stress or depression thanks to its intense euphoric highs, but equally it can be used as a natural pain relief or muscle relaxant.

Gorilla Glue thanks to its trichome covered buds gives off an incredibly strong aroma of diesel with notes of coffee and earthiness. The taste is a strong skunky taste with undertones of citrus fruits and earthiness.

Gorilla Glue is a 50:50 hybrid cross of Sour Diesel, Sour Dubb, Chem Sister and Choc Diesel.


THC Bomb

Highest THC strains THC Bomb

THC Bomb feminised was the first ever strain produced by the little known Dutch breeder Bomb Seeds. It is their flagship strain first introduced to the cannabis scene in the early 2000's.

This super high THC strain was recently lab tested and came back at over 32% THC, which is why we had to include it in our highest THC strains 2021 list. The 32% THC is even higher than is stated by MSNL or the Breeder. The true potential of this strain is still to be discovered by the wider cannabis community, but if you are feeling adventurous and want to grow something that not so many other growers will have then THC Bomb is the strain to grow.

THC Bomb is an indica dominant hybrid that will grow short and squat with the average height reaching 100-180cm. It will grow in a typical Christmas tree style shape, with a thick foliage that is clustered with dense solid buds. You can expect impressive yields from this strain of up to 600g/m2, which is astounding for a strain that has such high THC levels.

Because of its short stature, THC Bomb is a great strain for growing indoors. I have seen great results when using the ScrOG method combined with some defoliation to manipulate its shape and really take advantage of the bushy plant. If you are looking for a strain that has both knockout THC levels and big yields, then THC Bomb is the perfect strain.

THC Bomb is a super powerful indica dominant strain that will leave you feeling relaxed and at time couch locked. The first smoke of this strain will give you a rush of euphoria that will gradually slip into a heavy full body indica stone. Like all high THC strains users have reported dry mount so keep a drink nearby to quench your thirst.

Because of the indica heavy high from THC Bomb, it is a great strain to smoke at night time to combat insomnia.

THC Bomb has a sweet earthy aroma with hints of citrus fruits. The taste is earthy with sweet undertones reminiscent of tropical fruits.

Bomb Seeds keep the genetics of their flagship strain a mystery, what we do know is that it is a knockout mix of their Bomb #1 and an unknown indica.


Bruce Banner 3

highest thc strains Bruce Banner

Named after the marvel comic book character Bruce Banner, the cannabis strain is more like his angry alter ego, 'The Incredible Hulk'. At an impressive 30% and over, the THC levels of Bruce Banner are not to be taken lightly. Unlike most high THC strains Bruce Banner is a Sativa dominant hybrid that will leave you feeling uplifted but still hazy.

Bruce Banner won the High Times Cannabis Cup in 2013 and at the time the sample was tested at 28.35% THC which made it the highest THC strain tested in the history of the High Times Cannabis Cup. Renowned for being one of the highest THC marijuana strains in existence Bruce Banner #3 is a must try for any cannabis connoisseurs that enjoy strong weed. 

Bruce Banner #3 thanks to its sativa heritage is a tall plant that has been known to display three main phenotypes, all three with incredibly high THC percentages.

Physically Bruce Banner is a stunning plant to look at. In flowering the plant develops bold green leaves with vibrant colored buds covered in orange and brown pistols. Towards the end of flowering the buds will be completely covered in trichomes that make the plant glisten and incredibly sticky to the touch.

This is where Bruce Banner really comes into its own and why it makes it onto our highest THC strains 2021 list. It is likely that you wont have ever smoked anything as strong as Bruce Banner before, so go easy on your first smoke. On your first inhale you will experience a big hit that will make your head feel hazy and slightly stunned, some have experienced such relaxedness that they cannot even think for the first few seconds. This gradually leads into a feeling of utter euphoria as the body numbing buzz hits you. Thanks to its sativa genetics you will find that despite its high THC percentage, Bruce Banner does not give you the couch locked feeling that most high THC strains give. But instead gives you a more creative and sociable high perfect for a strain to kickstart the day with.

Bruce Banner #3 smells incredibly pungent from the moment the plant begins to develop flowers. The smells will be strong skunky aromas typical of cannabis plants but also with undertones of candy and citrus fruits. As you dry the bud Bruce Banner will begin to develop more floral notes and only when you have fully cured it can the full depth of smell be truly appreciated.

It is advisable to use a good carbon filter when growing this strain due to the strong odor the plant is known to produce.

The flavours of Bruce Banner #3 are even more appealing than the smell, as the crackle of your first smoke is inhaled you mouth will be filled with flavours of citrus fruits with a sweet candylike aftertaste that is reminiscent of a hot summers day.

Bruce Banner #3 is a hybrid strain but with 60% Sativa dominance bred from OG Kush and Strawberry Diesel. The two parent strains blended together to create the perfect combination of a high THC strain that is a great smoke.


Girl Scout Cookies

Girl Scout Cookies cannabis bud

Girl Scout Cookies (also known as GSC) is a super potent Californian strain created in 2010/2011. GSC is a cross of two popular strains; Durban Poison and OG Kush combining the best traits of both indica and sativa. 

Girl Scout Cookies is also known as Berner Cookies because the strain was supposedly created by rapper, Berner (otherwise known as Gilbert Millam Jr.). 

Since its creation Girl Scout Cookies has become something of a legend and is now one of the most smoked strains around the world. GSC is a very high THC weed strain, coming in only just behind the likes of Gorilla Glue and Bruce Banner 3 at 28% THC.

Girl Scout Cookies is not a strain for huge yields, but it more than makes up for this with its sweet tasting highly potent buds. 

When you grow Girl Scout Cookies you will see that the strain is a perfect mix of sativa and indica. She will grow an average height of around 180cm making it an easily manageable strain to grow indoors. One of the benefits to growing Girls Scout Cookies is its natural ability to pest and mold resistance. 

Girl Scout Cookies is a beautiful strain to look at and when in full flower you will see the bright green buds surrounded by purple leaves and vibrant orange pistols. 

Lab tested at 28% THC Girl Scout Cookies makes it to third place on our list of the highest THC strains 2021. As a cannabis connoisseur Girl Scout Cookies is a strain that I believe everyone should try. It is a perfect mix of uplifting sativa buzz combined with a relaxing sedative effect that will lead you into a deep sleep. The initial inhale will give you an intense cerebral rush followed by a more mellow full body indica stone.

Because of its uplifting and yet relaxing effect on the body Girl Scout Cookies is a great strain for those suffering with depression or stress. One puff on this and you will feel like you really don't have a care in the world.

Possibly the most impressive aspect of Girl Scout Cookies is the taste and smell of the buds. When you break open a freshly harvested bud your nostrils will quickly fill with the sweet smell of fruits with light earthy undertones. 

The taste of Girl Scout Cookies is even better than the smell. As you light up your first sampling of this strain you will get a sweet smell, not too dissimilar to freshly baked cookies. On the first inhale you will get a sweet sugary flavour with hints of cinnamon and citrus fruits. The perfect smoke to end a long day with.

Girl Scout Cookies is a hybrid mix of OG Kush and Durban Poison.


Banana Kush

MSNL Seed Bank Banana Kush

Our highest THC strains 2021 just wouldn't be complete without Banana Kush. An indica dominant hybrid cross of Ghost OG and Skunk Haze this Californian strain has some strong genetics. The result is a potent high THC mix of both sativa and indica that gives you an unforgettable high. The THC content can vary depending on how it is grown and where it is purchased.

A recent lab report came in at at an impressive 27% THC, however Banana Kush is a relatively new strain to the cannabis industry so its full potential may still be to come. 

As expected from an indica dominant strain Banana Kush stays short and busy with compact buds. As the plant reaches the middle of its veg cycle you will see a huge increase in the large fan leaves and gradually you will see the bud sites begin to develop. The plant is a deep green colour with dense buds that have a yellow hue to them. As the plants buds develop you will see one large central cola that forms. If you train this plant properly using LST or ScrOG you will see multiple large bud sites and a big increase in yields.

The smoke of Banana Kush is intense with an initial heavy body stone, clearly from the indica heritage. This is balanced out nicely though and thanks to its haze genetics you will feel uplifted nut super chilled. Banana Kush is a strain that should definitely be reserved for night time use and thanks to its heavy indica high it is a great strain for relaxation or anyone suffering with insomnia.

As would be expected, when Banana Kush nears harvest you will get the typical earthy scent from the strain but the prevalence of Banana is definitely there. The smoke is incredibly smooth with a spicy earthiness to it and a hint of sweet banana undertones.

Banana Kush is a 60:40 indica dominant cross of OG Kush and a Banana father strain.


Skywalker OG

The Skywalker OG cannabis strain is a hybrid bred from the parent strains Skywalker and OG Kush. This potent strain has an 80% indica/ 20% sativa balance. It offers a full-body high that is relaxing yet energetic at the same time, making it a strain that will offer both relaxation and creative energy.

This high THC weed strain possesses an incredibly complex aroma of pine, lemon, and diesel. The high from this hybrid is soothing and great for relieving headaches and pain without causing lethargy or couch-lock. She has a THC level that ranges from 15-26%.

Skywalker OG cannabis strain has large chunky buds that are light in color and have abundant sticky trichomes. The bright orange hairs on the plant are thick and give off a citrus smell. A dense layer of crystals that sparkle like stars makes Skywalker OG even more appealing to those who love to see many trichomes.

This strain is an indica dominant hybrid that has been bred to be highly potent. The type of high it can provide makes it a popular choice among connoisseurs. It gives your body a relaxing buzz while keeping your mind clear and functional.

We recommend Skywalker OG for experienced smokers only, as this strain can cause potential side effects like dizziness and paranoia in some newcomers who are not used to smoking. You can start with a tiny hit, and if that doesn't overwhelm you, try going a bit bigger.

Once you have taken a few hits of Skywalker OG, you'll notice a sweet yet spicy flavor come through with subtle hints of herbal beauty. The smoke is smooth and creamy with pine undertones. Skywalker OG has a gorgeous bouquet of woodland incense that will make heads turn with each toke.

Skywalker OG is a hybrid cross of Skywalker and OG Kush.



Highest THC strains Zkittlez

Zkittlez was introduced to the cannabis scene in 2015 and won the Best Indica category at the in its first year at the 2015 High Times Cannabis Cup in Michigan. Named after the fruity sweets ‘Skittles’. Zkittles is not only a great tasting strain, but is also highly potent too with over 25% THC. Zkittles is also very visually appealing with its vibrant coloured buds that certainly give it a degree of bag appeal.

Not the highest THC strain on our list, Zkittlez has been lab tested at over 25% THC which is still not something to be scoffed at. For growers that enjoy a sweet fruity tasting cannabis strain that will also send you to sleep at night you cannot go wrong with Zkittlez.

Zkittles is a truly beautiful strain that really does live up to its reputation. The plant is a vibrant emerald green colour with large solid buds and various shades of green and purple clustered with orange pistols. 

Zkittles is an indica dominant strain that reaches around 100 – 180cm in height. She is a compact plant with a healthy, dense foliage consisting of your typical large indica fan leaves. Zkittlez is a versatile strain that can be grown both indoors and outdoors. Its short to medium height makes it a great strain to grow in a tent using techniques such as LST to increase its already large yield (500 g/m2).

Zkittles is both high in THC with percentages of up to 25% and also decent yields of around 500g/m2 making it a perfect strain for cash croppers looking for a potent plant to grow.

Zkittles gives its users a vivid cerebral high that will make you feel as though time has slowed down. This leads into a feeling of utter euphoria developing more into an indica body stone that will have you feeling relaxed and out for the count.

Zkittles is a perfect strain for smoking after a stressful week at work when you just want to relax in the evening and let the time pass by.

Despite its indica dominance, Zkittles is known to be one of the best strains for lifting your mood making it great for treating depression or anxiety.

Zkittlez bold and vibrant colours are just as impressive as its taste and aroma. When you finally break open one of your long-awaited buds, you will get strong aromas of citrus that almost smell like fresh lemon zest mixed with the sweet smell of summer berries.

The taste of Zkittles cannot be rivalled by many other strains. It is an incredibly smooth smoke with a fresh citrusy taste and sweet tones of tropical fruits.

Zkittlez is a 70:40 sativa dominant hybrid cross of Grape Ape and Grapefruit crossed with another undisclosed strain.


Do Si Dos

Highest THC strains Dos Si Dos

Dos Si Dos is an indica dominant hybrid strain, that is bred from the well-known Girl Scout Cookies lineage crossed with Face Off OG to give you a truly remarkable plant. With THC percentages recorded at well over 25% THC, Do Si Dos is a cannabis strain that will give you a full blown heavy indica stone. 

Growers that enjoy a relaxed high will love Do-Si-Dos. Being an Indica dominant strain she stays relatively short so is an ideal strain to LST.

Dos Si Dos will grow to a medium height of 100 – 180cm keeping true to its bushy indica shape. If you want to grow a strain that is beautiful and still has a knockout punch then Dos Si Dos is the strain for you. She will grow into a dense plant with bright lime green coloured leaves interspersed with solid dense buds. The buds are speckled with orange hairs and have a bluish-purple hue to them that tends to darken as the plant nears the end of its harvest.

This high THC strain will give you an unmistakably indica dominant high. The first inhale will give users a buzzy uplifting high and with more smoking it will gradually lead into a heavy sedative stone that will leave you feeling numb. Despite the sedative effect the high from Dos Si Dos is remarkably uplifting which makes it an excellent strain to combat stress, depression, or anxiety. It truly will leave you feeling like you have not got a care in the world.

The aroma of Dos Si Dos is pungent and skunky with powerful citrusy tones. Around halfway through the flowering stage the plant will begin to give off a powerful floral odour that is unmistakable. Stealth growers be aware, make sure you have a carbon filter fitted by this point!

Dos Si Dos is an Indica dominant hybrid cross of OG Kush Breath & Face Off OG.


Northern Lights #5 x Haze

Highest thc strains 2021

Although not the highest THC strain on our list, Northern Lights #5 x Haze has won multiple cannabis awards over the years including the High Life Cup and has truly cemented its status as a legendary strain. Bred by Sensi Seeds by crossing Northern Lights with a sativa dominant haze this plant is both a high yielding high THC monster of a plant with lab reports of over 25% THC. 

Sensi Seeds is the oldest cannabis seed bank in the world, steeped in history. They are renowned for producing some of the best cannabis in the world and have a reputation as being the original cannabis breeders.  

Northern Lights #5 x Haze is 70% sativa which becomes evident once the plant reaches the middle of its vegetative stage of growth at which point the plant has a sudden growth spurt and can almost double in height. Because her height can reach up to 300cm it is the perfect strain to grow outdoors, or alternatively if you are growing indoors prepare to do some plant training to taper its shape. Long swathes of bud will fill the gaps between the foliage and if grown outdoors the yields are immense.

If you want a high THC strain that is also uplifting and can be smoked during the daytime then Northern Lights #5 x Haze is the perfect smoke for you. As soon as you inhale the smoke flavours of Northern Lights #5 x Haze you will get an instant full body buzz that will leave you feeling happy and euphoric with a sense of creativity.

Northern Lights #5 x Haze produces a distinctive spicy aroma while growing that becomes ever more prominent the further the plant goes into flowering. When you smoke Northern Lights #5 x Haze the typical citrus flavour of sativas come through with undertones of pine and earthiness.

Northern Lights #5 x Haze is a 70:30 indica dominant cross of the famous Northern Lights and a Haze strain.



MSNL Seed Bank Gelato

Gelato also known as ‘Larry Bird’ is a super potent hybrid mix of two of California's most popular strains, Girl Scout Cookies Thin Mint and Sunset Sherbet, the result is something truly remarkable. This THC powerhouse has been recorded to have percentages of up to 26% which is enough to send even the most seasoned smokers into a deep sleep and push Gelato into the top ten of our highest THC strains 2021.

For growers who want a super high THC strain that is also great tasting Gelato is not one to be missed. Developed in San Francisco from a cross of Sunset Sherbet and Girl Scout Cookies Thin Mint Gelato has almost no CBD.

Gelato Plants are distinctive in appearance thanks to their vibrant emerald, green colour. When in the flowering stage of growth, they will develop a thick foliage that is clustered with fluffy buds. The buds will be light green in colour with purple hues and orange pistols that will gradually turn to a dark bronze as the plant nears its harvest. As you harvest the plant you will see that the buds will be almost white where they are so heavily covered with glistening trichomes.

Smoking Gelato is intense to say the least. Go easy on the initial inhales because the high creeps up on you and can lead to a couch lock eventually. At first you will feel a cerebral buzz with a sense of euphoria that with more smoking will lead into a sedative calm.

Many users that smoke gelato report it to be an effective strain to combat aches and pains.

The taste from Gelato is a distinctive sharp citrus fruit flavour with undertones of sweet forest berries which is where the strain got its name ‘Gelato’. 

As Gelato grows you will get aromas of pine when the plant is coming into its flowering stage with hints of lavender as the plant matures.

Gelato is an Indica dominant hybrid strain that was developed in San Francisco from a cross of two other high THC strains, Girl Scout Cookies Thin Mint and Sunset Sherbet.


Sunset Sherbet


Mamacitas Cookies

Sunset Sherbet is a delightful indica-dominant hybrid that showcases a unique combination of citrusy lushness with an uplifting high. It was born out of crossbreeding Girl Scout Cookies and Lemon Skunk, which produced a high THC weed strain that is rich in flavor. Sunset Sherbet has an intense aroma that varies from fruity to skunky, while its THC hovers between 18 % to 25 %.

Sunset Sherbet cannabis seeds offer a delicious, refreshing high. They're easy to grow and produce a bountiful yield. Perfect for growing weed indoors or out, they prefer a sunny and warm environment. Their bushy structure, medium-sized leaves, and compact nature make them appealing to new and experienced growers.

These beautiful buds were named for their intense sherbet colors. Its buds are covered in golden strands of trichomes, giving the bud a playful shimmer. The green and violet nugs sparkle with orange pistils and the bright colors create a sunset-worthy appearance. 

Sunset Sherbet has higher THC content than its parent strains. It is a multiple Cannabis Cup winner and is highly potent, so newbies should use small doses. If you are after a high THC weed that isn't going to knock you out, Sunset Sherbet induces strong cerebral effects without creating that couch-locked feeling. 

Users feel alert instead of sedated, allowing for pleasant and fun times. Its effects last several hours. This is one of those delightfully tasty strains that's easy to overindulge in. Its cerebral effects are deliciously combined with a tasty flavor. It's low-key, but there can be some dry eyes and mouth for most people.

You won't be fighting a negative taste or smell when you medicate with Sunset Sherbet. A citrusy aroma combined with a relaxing herbal flavor results in an enjoyable smoking experience. When you smoke Sunset Sherbet, it tastes like the sweetest frozen dessert. The citrus and mint flavors make this a pleasantry, similar to your favorite treat.

Sunset Sherbet is a cross of Girl Scout Cookies and Pink Panties.

Mamacitas Cookies are an indica-dominant strain that can help with appetite. This strain was created by crossing the well-known Girl Scout Cookies (aka GSC) with Nicole Kush. The high THC weed strain stimulates creativity and causes euphoria. It is a high-energy strain that has been shown to improve stamina and energy levels.

Mamacita's Cookie is a potent marijuana strain that will have you coming back for more. Named after the famous chocolate-chip cookies, this strain has a sweet and spicy aroma and taste. It is known to take away anxiety but may bring on paranoia. Take it easy when trying this indica dominant hybrid out for the first time.

The buds are light green to dark green and have a somewhat sticky texture. A heavy layer of frost covers the buds, which is typical for this strain. These crystal-coated flowers have terpene profiles, including myrcene and limonene. The buds are a beautiful display of orange hairs speckled over dark green leaves. Again, you can spot some rosettes of milky white trichomes from around the buds. 

Mamacitas Cookies is an indica-dominant hybrid with very potent effects. You'll feel a burst of euphoria as soon as you take your first hit. What follows are waves of uplifting, creative, and motivating sense of mental energy. This upbeat, euphoric cerebral high is balanced by a body high that leaves patients clear-headed and energized throughout the day. A must for those who need a little help getting things done.

Wonderfully sweet on the exhale, Mamacitas Cookie lives up to its name. The flavor of sweet tarts with a hint of spice can be detected in taste and smell, while the effects are uplifting and long-lasting. 

Mamacitas Cookies is a cross of the world famous Girl Scout Cookies and Nicole Kush.


Purple Kush

Purple Kush, otherwise known as "PK," is distinct in its taste and smell. While it may be short in stature, PK is one of the most resilient strains on the market. This purple-toned beauty has been grown all over the world. It combines the elite genetics of Purple Urkle and OG Kush to create a classic strain that tenders dense buds with red and purple hues. Purple Kush also contains a high level of THC that ranges from 20% to 25%.

Purple kush is a hardy plant, one of the most popular in the cannabis community. It flowers within 8 to 10 weeks and has a high yield. This high THC strain gives you a clear-headed, mellow buzz that will send you into a new realm of relaxation.

Although not the most potent on our list of the highest THC strains 2021, Purple Kush certainly has plenty of bag appeal. Boasting a blend of vibrant reds and purples to fluorescent greens, creating a unique color palette. Its beautiful and bountiful flowers are dusted with shades of purple and coated in frosty trichomes. Purple Kush is a heavy indica strain that is famous for its big indica buds. The nugs are frosted with lilac purple hairs and sticky with crystals.

This is one of the strongest weeds that leaves you with two large, closely timed bursts of energy. It begins to kick in about five minutes after smoking, with a burst that eases the mind and body into a calm state. After this initial climb, Kush's second rush brings on an elevated mood that keeps you mellow and relaxed while letting your negative emotions subside.

You become very relaxed and comfortable as if you were sitting in a bubble bath. Effects of Purple Kush may also include a feeling of euphoria, happiness, and introspection. Pleasant and euphoric, the Purple Kush cannabis strain is often used as a medical aid to help with insomnia, anxiety, and depression. It's also used for bouts of nausea and stress.

Taste Purple Kush, and it is smooth and sweet. It tastes like earthy pine with a hint of anise when smoked and has a slightly sweet berry aftertaste. The taste is usually felt more in the back of the mouth than in the front, where it lingers longer than most other strains 

Purple Kush is a cross of the world famous OG Kush crossed with Purple Urkle.


Black Gorilla

A cross of Gorila Glue and Bright Berry, Black Gorilla Feminized gives you all the effects of your favorite Indica-dominant strains. At 25 percent THC, this cannabis strain has an extremely high level of psychoactive properties. This dank beauty has an earthy flavor and aroma with overtones of strawberry bubblegum. A relaxing indica, this strain is excellent for unwinding after a tough day's work or playing a little too hard on the weekend.

The high from Black Gorilla is long-lasting and physical (body buzz), and it's also good for relief from pain. Some feel it helps with spiritual meditation, too.

The most visible trait of this strain is the heavy layer of crystals that seems to cover every inch of this ganja. It's a deep green, almost black shade, and reddish once broken up. There are long orange pistils present as well, and plenty of them. While you won't get much in the form of coarse kush powder with this strain, it has plenty of sticky resin that makes for some potent smoke!

A cross of two super potent parents, Black Gorilla was bound to be one of the strongest weed strains. Its high gives the user a happy, uplifting feeling with less of the couch locked effect felt from its parent Gorilla Glue.

The buzz experienced with this type of weed may be related to its Sativa signs, coupled with its intense THC levels. This strain is best suited for those who have depression or are going through a difficult time. A higher level of THC can offer an instant boost in mood and motivation. 

Expect a primarily sweet blend of terpenes, including that classic berry strain aroma, with the addition of black molasses. A peppery taste will rise from the depths of each exhale. This marijuana strain is the perfect choice for those who enjoy a calming effect with a subtle hint of fruitiness and chocolate.

Black Gorilla is a hybrid cross of Gorilla Glue and Bright Berry.



Runtz is an indica-dominant hybrid with a terpene profile that makes your mouth water. This plant's buds take on a sweet but hardy citrus flavor with earthy overtones. The high THC weed that it produces gives users a feeling of euphoria and bliss, while its indica dominance helps create a strong feeling of relaxation throughout the body and mind. Its THC levels have been measured at 25% but can test up to 29%.

Runtz is a hearty hybrid strain that manages to packs a punch well beyond its weight class. Its name comes from the dainty, minuscule size of the buds it produces when grown in an indoor environment. A sweet flowery aroma with subtle floral tones radiates off the sugar-coated buds and permeates the space around connoisseurs as they ignite this delectable delight.

Its buds are multi-colored with streaks of deep violet, magenta, blue, and forest green hues. The nugs are incredibly dense and a bit stretchy, with thin orange pistils nearly impossible to see until up close. Its trichome coverage is heavy and visible even from a distance, adding much-appreciated character to its overall appearance.

With an average THC content of 25% its no wonder why Runtz is straight in at number 15 of our high THC strains 2021 count down. She may seem mellow at first, but with a high, that is both energetic and calming. Runtz Muffin delivers massive relaxation with every toke. She's not for the faint of heart, but if you take your time and give her a real chance, Runtz is a treat for any occasion where you can kick back.

The Runtz Muffin cannabis strain is best for those who want to relax and unwind. This is a great strain to help alleviate anxiety, stress, physical pains, and muscle spasms. It can also boost energy, so this may be beneficial for those suffering from fatigue or depression.

If you enjoy fruity and sweet cannabis strains, the Runtz Muffin cannabis strain is for you. The buds are very sticky, with fruitier flavors and hints of a mild citrus flavor. With just one sniff of her sticky buds, you'll be greeted with a fruity, sweet, candy-like flavor with a pronounced citrus tang.

Runtz is a hybrid cross of Zkittlez and Gelato.


Grandaddy Banner

This high THC weed strain was created by crossing two legendary strains, Granddaddy Purple and Bruce Banner. With THC levels of up to 28%, Grandaddy Banner produces some of the strongest weed around. Appearance wise the classic indica produces glistening, bright green, and amber-colored nugs covered in crystals. The taste begins with earthy tones before giving way to sweet and floral overtones. It has been known to produce couch-lock as well as bouts of uncontrollable laughter and intense hunger

With an earthy pine and berry scent that grows stronger the closer you get to the trim, this bud is perfect for the connoisseur looking for a serious nighttime medical strain. Grandaddy Banner provides a head-heavy sensation that leaves you feeling uplifted and focused. This strain has gained a reputation for unwinding muscle tension and calming anxiety.

Visually, Grandaddy Purple casts a heavy hunk of sticky green hair and an oversized coating of crystal-coated trichomes on the outside of its large, dark green nuggets. These dense, tight buds are frosted with sticky crystals and give off solid fruity smells over rich notes of earthy flavors. When dried, the buds are compact and solid.

Banner produces substantial cerebral effects that some have described as "speedy," accompanied by slight physical euphoria and a relaxed body high. It is most often compared to classic Indica strains such as Northern Lights, Hindu Kush, or Afghan Kush. Not recommended for novice consumers due to its potency.

Grandaddy Purple is one of the strongest weeds available. This bud has a very distinct flavor that combines sweet and sour flavors on the inhale. There is an earthy bitter taste on the exhale, similar to that of grapefruit.

Grandaddy Banner is a hybrid cross of Granddaddy Purple and Bruce Banner.


Birthday Cake

Birthday Cake is an Indica-dominant strain that has been around for quite a while. It features a genetic legacy that includes Cherry Pie and Girl Scout Cookies. This high THC weed strain offers a powerful psychedelic high that is linked with pronounced physical relaxation.

This top-shelf cannabis strain delivers a rich, long-lasting high perfect for winding down after work. Birthday Cake makes it into our top 20 highest THC strains 2021 because under the right conditions THC levels can be 27% or more, so be sure to mind your dosage. With notes of earthy sweetness, this strain's earthy pine and fuel flavors are sure to please any cannabis connoisseur. Birthdays are better with cakes, especially when they're filled with buttery frosting and sprinkles of THC.

The dense and sticky nuggets are a dark forest green with flecks of orange, red, and purple. Indoors, these colorful buds take on a purplish hue in the flowering stage. The crystals that cover this delicious bud give it the appearance of having been frosted with a generous sprinkling of sugar.

The intoxicating effects of this strain are described as initially uplifting and energetic, leaving users feeling blissful and happy. As the body high comes on, it's a perfect balance between a cerebral and physical experience. 

Happy, hungry, and creative are just some of the words people use to describe their experience with this strain. It provides an energy boost that many find extremely useful during the day, but it may cause some paranoia in some individuals. 

The Birthday Cake cannabis strain is known for its aroma like "frosted cupcakes" and fruity sweet taste. Upon inhale, you can expect raspberry and vanilla flavors to flood your palate with a powdered sugar finish. Upon exhale, the flavor packs a savory and memorable punch as the blueberry's candied citrus and pine flavor kick in. The best part about this strain is that it tastes just as good as it smells, with citrus and vanilla notes reminding us of yummy, rich birthday cake.

Girl Scout Cookies crossed with Cherry Pie.


Blue Dream

The excellent Blue Dream is one of the most popular marijuana strains in the United States. This hybrid is a cross between Blueberry and Haze. You will recognize it by its rich, blue buds with dark orange hairs. As the name implies, this strain gives off a dreamy high that is not overpowering but uplifting. The THC content averages at 18-22%.

Blue Dream is an award-winning sativa dominant hybrid strain that many patients turn to for treating conditions such as anxiety, PTSD, depression, insomnia, and headaches. This high THC strain has powerful sativa effects and lands you in a happy and euphoric place. It features a robust musky aroma with sweet berry undertones and notes of citrus.

Blue Dream is one of the strongest weeds with stunning, dense flowers. It has large, elongated, and light lime-green colored nugs with dark forest undertones. A thick layer of sandy-colored hairs covering the bud adds an extra visual pop to this strain's beauty. 

Although not the strongest weed strain on our list Blue Dream is a sativa-dominant hybrid that you'll be happy to wake and bake to every morning. The high starts with an uplifting head buzz that leaves you feeling motivated and creative. Once the initial onset begins to wear off, the euphoric and relaxing properties of Blue Dream come to the fore. A body high will ease over you, putting your muscles in a state of relaxed repose. You may even nod off here and there while you stay mentally alert through the haze.

The strain's aroma mixes fruity blueberry flavors with aromas of fresh mango and sweet, earthy vanilla. Its taste mirrors the smell, flowing into a warm, compelling finish with undertones of herbal spice.

Blue Dream is a hybrid cross of Blueberry crossed with Haze.


White Fire OG Auto

Our list of the high THC strains 2021 wouldn't be complete without an autoflower. White Fire OG gives you uplifting buzz  with a cerebral undertone. The nose-tingling aroma is immediately noticed upon opening the container and experiencing its cleansing smoke. The strain helps alleviate symptoms of stress and depression while leaving you feeling relaxed yet focused. Its light to medium THC content (8-15%) creates a powerful cerebral effect.

White Fire OG Auto Fast Version has some similar traits to its predecessors. This strain has a predominantly sativa high as it gives you an uplifting mind buzz that hits very fast and then seems to morph into a euphoric, creative high. The cerebral effect allows you to stay active. It has a slightly earthy, woody odor with a sweet, creamy taste.

The White Fire OG strain, like the OG Kush, will be light green with amber streaks. The buds have long orange pistils with large dense colas that crumble under negative pressure. Its amber hairs are finished with thick, robust crystal-coated trichomes on every sheath.


White Fire OG is a rare hybrid strain that makes its presence known throughout the growing and high. The strongest weed strain on our list that is also an autoflower, White Fire OG is a potent sativa dominant hybrid with a very mellow, relaxed yet functional high. If you enjoy a euphoric and long-lasting Indica stone with clear sativa effects and flavors, this is the strain for you.

The strain's smell takes on a fruity spice character with hints of lemon and an earthy undernote. On smoking, the fruitiness intensifies and combines with an anise/basil scent. Upon exhale, a light, coffee-like taste appears along with an earthen flavor similar to fresh soil.

A hybrid Cross of White Fire and OG Kush.


Auto Cinderella Jack

Coming in at number 20 on our list of high THC weed strains, Auto Cinderella Jack is a mostly indica cannabis hybrid variety that is a cross between Auto Jack Herer and Cinderella 99.  But don't be fooled, this strain can reach THC percentages of up to 25% so it is nothing to be scoffed at.

Auto Cinderella Jack gives users a dreamy fusion of flavors, with ripe fruit aromas of peach and mango paired nicely with the earthy, skunky notes. 

A consistent producer, this plant delivers a potent combination of relaxation and rejuvenation that makes it easy to unwind after a long day. The predominant effects result from a THC level that's been measured as high as 25%. These buds are deep green with amber tips and dark orange hairs. 

The Auto Cinderella Jack cannabis strain is a highly compact plant. It is a medium-sized plant but can make a nice bush if there's enough time before harvest and the grow space allows. The buds are formed in long branches that look like a tree has been overloaded with Christmas presents. These branches are firm but not rock hard and have what seems to be endless layers of beautiful white crystals. The glistening trichomes also make it a treat for the eyes.

Whether you're in the mood to relax or want to get your heart pumping, Auto Cinderella will deliver a powerful effect that keeps you going. Auto Cinderella will leave you feeling sleepy but with bursts of energy that can help you get chores done, as well as making you more social and talkative. Its medicinal qualities include pain relief, insomnia, appetite stimulation, anxiety relief, and muscle relaxation.

This enchanting strain took home the trophy in Los Angeles for best smell, and we can see why. It has a powerful sweet aroma with buttery undertones and subtle minty spice that is pleasant. The taste is exceptional, with an initial buttery flavor that gives way to rich berry and mint flavors.

Auto Cinderella Jack is a hybrid cross of Auto Jack Herer and Cinderella 99 produced from a collaboration between Dutch Passion and Buddha Seeds.

Highest THC strains 2021 growing guide

THC is the compound within cannabis that gives us the psychoactive effect when its smoked, in other words, it gets you high. Many regular weed smokers will have noticed an increase in tolerance to THC over time, the more often you smoke the more it takes to get you get you high. If this is you then growing high THC strains and learning how to increase its THC percentages is exactly what you need to know. There are five main factors that will affect the levels of THC found in the cannabis you grow, pay attention to these to grow some of the strongest weed:

Genetics – Grow a high thc strain

Starting with the right genetics is the most important factor in determining how much THC your weed will contain. Lets say you choose a strain that can produce 22% THC, this number is the upper limit of how much THC this particular strain is capable of producing under ideal conditions. How well you grow the plant is also a determining factor of THC percentage, so you could end up a lot less than 22% THC if everything doesn’t go completely to plan. Use the list above of the highest THC strains 2021 to choose a strain. By growing one of these strains that are genetically inclined to produce potent bud,  you give yourself the best chance of producing super high THC weed. To put it simply, if you want to smoke the strongest weed, then you should first look to grow using highest THC strains. Buying a strain from our list above would be a good start.

Time your harvests for the strongest weed

During the flowering stage cannabis plants usually have a 2-3 week window when the bud is at its most potent, if you are growing the highest THC strains you should aim to harvest within this window. As the plant matures and comes towards the end of its flowering stage you should periodically asses the trichomes using a magnifying glass or jewellers loupe. When the trichomes become milky white in colour and around 70-90% of the pistols have turned dark and began to curl in, this is when the weed is at its most potent and should be harvested for optimum THC levels. Learn how to time your harvests to perfection.

Good plant health = high thc weed

If you want to produce high THC weed then you need to ensure that your plants are happy and healthy. This means controlling your grow room climate and avoiding those common mistakes such as over and under watering, nutrient burn, mold and bud rot, heat stress and plant pests. The more your plant is able to focus on growing and developing, the better the quality of bud will be and the higher its THC will be.

Quality light produces the strongest weed

Light is like food for cannabis plants, without enough good quality high intensity light cannabis plants will not grow to their full potential. During the flowering stage cannabis plants use light to power the growth of buds so it is important to make sure that they are getting the right type of light and the right intensity during this period. If you want to grow good high THC high yielding strains you need to use high intensity lights such as LED or HID bulbs to grow them. Outdoors you wont have as much control over how much light a plant gets. But timing your grows will have a big impact on both the yield and THC levels of a plant. For example, planting your seeds in March – May will give you plenty of daylight during the flowering phase of growth. Plant them in July or August and it may be too late to get the full potential from the plant as summer draws in.

Cure your bud for high thc weed

Once you have harvested and dried your buds, to improve the flavour and potency it is important to burp and cure them. The most common method of doing this is curing buds in jars, to do this you simply store them in a jar or container for a couple of weeks, periodically shaking them and opening the jar to burp them. Although there is little evidence that shows this process increase THC levels, it does improve the  perceived potency of the bud, as well as the taste and smell, after all, there’s no point having the strongest weed if it doesn’t taste good as well.