What Are the Strongest Cannabis Strains?

Updated 02/20/2018

Looking for a cannabis strain that will challenge your tolerance or stand up to stubborn medical symptoms? Readers ask us all the time which strains are the most potent, and while that depends on a variety of factors from growing techniques to phenotypic variation, we’ve put together a list of strains that tend to deliver potent euphoric effects thanks to strong genetics and selective breeding.

While THC is the main driver of potency, it’s important to understand the important role terpenes play in enhancing and shaping the strain’s high. Terpenes like myrcene, linalool, and limonene refer to aromatic compounds that lend cannabis its unique array of smells, and a cannabis strain rich in both terpenes and THC often delivers a more remarkable experience than a product that lacks chemical diversity.

What Are Cannabis Terpenes and What Do They Do?

A Selection of the Strongest Cannabis Strains

Below are the mean THC levels of a few cannabis strains featured in this list. Note that these represent their average potency across several testing labs; you’ll undoubtedly come across samples with higher or lower THC levels in your own strain exploration, but this gives you a baseline idea of how these strains compare.

Note: You can filter “potent strains” on dispensary menus to see if any of these recommendations are available near you.

THC levels in strongest weed strains
Potency data derived from six of the largest testing labs in Washington State. Click to enlarge. (Elysse Feigenblatt/Leafly)

GSC (f.k.a. Girl Scout Cookies)

High THC Weed Strain: GSC

Terpenes in GSC marijuana strain

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GSC (f.k.a Girl Scout Cookies) hauled its way up the ladder of fame in recent years, and it isn’t hard to see why. The genetics in this hybrid are strong, with a THC content that regularly tests above 20%. Expect a crushing wave of blissful euphoria that enshrouds both mind and body with warm relaxation for hours.

Leafly User Review:

“Incredible jelly foot. Very nice body pudding. Creativity mixed with amazing peaks of HD colors.” –herbknight

Kosher Kush

High THC Weed Strain: Kosher Kush

Terpenes in Kosher Kush marijuana strainFind Kosher Kush Nearby

Kosher Kush first blessed the world with its presence in 2010 and has been nabbing Cannabis Cup awards ever since. Its genetic background may be a mystery, but this indica’s keepers at DNA Genetics have refined a champion strain that consistently breaches 20% THC. Wrapped in a thick blanket of crystalline resin, you’ll hardly need a closer look to see that this tranquilizing indica is not one for the novices.

Leafly User Review:

“I can’t feel my face… or my arms, or my feet, or anything for that matter. It’s as though I’m a weightless entity with a somewhat foggy-consciousness, floating on the patio.” –ricegrain

Ghost OG

High THC Weed Strain: Ghost OG

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Hiding in a white cloak of crystal resin, Ghost OG is a strain that is bred for its high-octane euphoria. Said to be a cut off the original OG Kush, Ghost OG’s potency is toned by a symphony of terpenes that fuel this strain’s powerful THC engine. Find a comfy seat and prepare to be swept into a powerful, euphoric current perfect for relaxing.

Bruce Banner

High THC Weed Strain: Bruce Banner

Terpenes in Bruce Banner marijuana strain

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Bruce Banner, appropriately named after the Hulk’s alter ego, is a heavy-duty hybrid with a staggering THC content. Rated the strongest strain in 2014 by High Times following its victory in the 2013 Denver Cannabis Cup, Bruce Banner has since carved itself quite the reputation. Powered by OG Kush and Strawberry Diesel genetics, Bruce Banner delivers a dizzying punch of euphoria that anchors your body in deep relaxation.

Ghost Train Haze

High THC Weed Strain: Ghost Train HazeTerpenes in Ghost Train Haze marijuana strain

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In the last few years, the Cannabis Cup leaderboards saw a new rising star: the lively and vigorous sativa known as Ghost Train Haze. Bred by Rare Dankness Seeds, Ghost Train Haze had the highest THC content of any 2011 Cannabis Cup submissions, weighing in at 25.5% THC. Inheriting genetics from Ghost OG and Neville’s Wreck, this sativa’s potency takes form in a jolt of euphoric energy that goes straight to the head, feeding focus and creativity.

Leafly User Review:

“My initial response was yelling. It’s almost unreasonably potent. Smooth and citrusy too, but potent. Did I mention it was potent? It was potent. A next-level sativa. Made me feel like a marijuana n00b up until now. CAREFUL, it’s potent.” –thepiginzen


High THC Weed Strain: Chemdawg

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Chemdawg is a classic strain whose unforgettable potency keeps a vice grip on its fan base. Ripe with the scent of acrid fuel, Chemdawg delivers an unforgettable flavor profile alongside its invigorating euphoria, inviting creativity alongside firm stress relief.

Leafly User Review:

“I feel like I’m in gravy and it’s a real good time.” –powwow31


High THC Weed Strain #5: Gg4Terpenes in GG4 marijuana strain

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GG4 is named for the stickiness of its resinous buds, and this hybrid certainly lives up to her name. It isn’t rare for GG4 to hit the mid- to upper-twenties in a potency analysis, and she’s got multiple Cannabis Cup awards to back that claim up. But we doubt you’ll need the proof when this hybrid’s got you gorilla-glued to the couch in stupefied contentment.

The White

High THC Weed Strain: The White

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Named for the whiteout of crystal resin cloaking her buds, The White has become a godsend for breeders looking to improve the potency of their genetics. Routinely testing between 20-28% THC, The White delivers a disorienting blizzard of euphoric delirium that commands relaxation.

Death Star

High THC Weed Strain: Death StarTerpenes in Death Star marijuana strain

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With a THC profile that typically dances between 20-24%, Death Star will surely wreak as much havoc as the Galactic Empire. Using its great psychoactive forces, this Sensi Star and Sour Diesel hybrid commands you to chill out as it imposes powerfully euphoric and sedating effects.

Leafly User Review:

“There’s no hiding the high with Death Star. We went Christmas tree shopping in the bitter cold. It took us about 45 minutes to pick out a tree…it ended up being the very first tree we saw. Then went to a bar and I confused a mirror for a window.” –hoobear

White Fire OG

igh THC Weed Strain: White Fire OG

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Born from The White and Fire OG, White Fire OG (also known as WiFi OG) is a force not to be trifled with. Testing data shows the impressive THC potential of this hybrid, with average levels falling between 22-29%. Its uplifting effects launch your mood into the clouds, an elevated feeling that will shake creativity and happiness wide awake.

Explore More Potent Cannabis Strains

Can’t get enough potent, high-THC strains for your stash jar? Here are a few more heavy-hitters for you to seek out at your next dispensary visit.

Which other heavy-handed strains belong on this list? Tell us about them in the comments section!