brain neurons

Does smoking cannabis kill brain cells?

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Table of Contents

Recent research has shown that yes, smoking nicotine can kill your brain cells – and stop new ones from forming. It’s the latest death knell for smoking cigarettes as a habit. Now we know it’s bad for your heart, your lungs, and your brain. Those are parts of you that you tend to need.



But does smoking weed kill your brain cells?

That’s another question entirely. Because despite 1970s and 1980s-era anti-drug campaigns and the occasional more recent statements of politicians and other public figures with only the loosest possible connection with fact, smoking weed doesn’t kill brain cells.

In fact, in smaller doses, cannabis seems to have positive effects on the brain. This is one of the reasons why marijuana is currently being studied by so many groups around the world for its medicinal potential.

However, that isn’t the end of the story. Weed has a complicated relationship with the brain. If you want to learn more about everything from the old-school weed kills brain cells myth to the actual reality of cannabis’s effects on the brain, here’s everything you need to know:

brain neurons

The “weed kills brain cells myth” – where does it come from?

Up until very recently, marijuana has long had an image in popular culture that is wildly divorced from reality.

From Hollywood films showing marijuana users experiencing “trippy” effects more appropriate for something like LSD or some other kind of hallucinogen, to news reports claiming that individuals went on “cannabis-fueled rampages”, anyone with even a passing familiarity with cannabis’s effects would be able to spot liberties being taken with the truth.

These “popular myths” didn’t arrive in the public consciousness by accident. Successive governments and other official bodies in the US and large parts of the “western world” have long lumped cannabis in with much harder, harmful drugs.

Once, this might have been understandable. For example, back in the 1930s, the infamous “drug awareness” film Reefer Madness showed young actors pretending to go mad and see things after smoking marijuana. Yet in the 1930s, even tobacco’s negative effects on the body were not well known.

This film was resurrected in the 1970s. It was followed by the still well-remembered 1980s anti-drug campaigns of the Ronald Reagan-era War on Drugs. You’ll probably have seen the most famous of these 1980s films. It’s the one with the egg in the frying pan with the grimly intoned “This is your brain on drugs” narration.

But by the time this advert was resurrected (and we really mean brought back from the dead at this point) in the 2010s, much wider scientific data on different drugs and what they do to the body had become available. Yet the myths still somehow persist.

brain cell neurons

So, smoking weed kills brain cells?

No, cannabis use does not kill brain cells. The only scientific evidence of cannabis having negative effects on brain cells is related to synthetic cannabinoids. These are things like “K2” and “spice”.

Natural cannabinoids have actually been shown to have neuroprotective effects on the brain. This means they protect your brain cells, activating processes like anti-oxidation that are good for your brain.

That’s why various cannabinoids are being studied for potential therapeutic uses against conditions like Parkinson’s Disease and Alzheimer’s. Other studies appear to show very low levels of THC may even have some ability to reverse memory issues caused by old age.

All of this research is definitely still at the “drawing board” stage. The reversal of brain age study was done on mice. But it goes to show that far from frying your brain like an egg, the effects of marijuana on brain cells are a lot more nuanced.


Marijuana doesn't kill brain cells

One important caveat to this is that all of the positive effects above were noticed when cannabis was being used in moderation.

When you start using marijuana in large quantities on a daily basis, the picture starts to look a whole lot different. It’s still not a case of “how many brain cells does weed kill?” But the science seems to show effects on the brain that are decidedly not so positive.

Two scientific journals – Neuroreport and Addiction Biology – have published studies that showed “chronic” users of marijuana had reduced gray matter volume in parts of the brain and that key proteins weren’t being produced at normal levels.

One study back in 2020 showed the size of the hippocampus in long-term heavy weed users continued to get smaller over time. As the hippocampus is the part of the brain that controls learning and memory, this should be a concern for anyone whose cannabis use is very high.

Again, this doesn’t mean that weed is killing brain cells. But it’s certainly not the positive effects that mild and moderate cannabis use seem to show!

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Moderation (and not smoking nicotine) are key

Does weed really kill brain cells? No. But chronic – that’s long-term, heavy – use is not good for the overall health of your brain. Neither is smoking anything containing nicotine.

Yet using weed in moderation actually seems like it could have some health benefits. They’re not set in stone just yet. But all the signs are pointing that way.

This means that if you are a chronic, heavy user, it might be time to start thinking about making some changes. You could consider:


1) Reducing your consumption

Could you start to reduce the amount of cannabis you consume? You don’t have to completely cut back overnight. If you’re smoking nicotine at the same time as you smoke cannabis – perhaps with tobacco in your joint, for example – this might actually be more challenging that you would expect.

Some experts have suggested that taking a “reset” period for your body each month might be enough to stave off the effects of chronic use. This would involve a 48-hour cannabis-free period every 28 days.

If you really wanted to cut down though, you could start off by trying to use cannabis only every other day. Your goal being to reduce your cannabis use to times that are very strictly and definitely necessary – or as an occasional treat instead of a constant indulgence.

There is another potential upside to this. For many people, buying less means you can buy better. Perhaps choose your favorite strain of weed and/ or a real all-natural, high-quality product rather than an affordable standard. To borrow an alcohol analogy, treat buying cannabis more like buying a fine bourbon or whiskey to sip every now and again instead of a cheap round of shots.

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2) Swapping out the nicotine for a vape

If you like to smoke marijuana in a classic joint, you’re doing your heart, lungs and – now we know – also your brain lots of damage simply by smoking that nicotine-packed tobacco at the same time as your cannabis.

Instead, switch out the old joint for a THC vape pen. Vapes these days are super convenient, easy to use, discreet, come in your choice of strains, and are ideal for all kinds of activities where rolling a joint can be a pain in the neck.

Vaping is always going to be better for you than smoking. There’s no smoke or combustion involved – the cannabis oil concentrate inside the cartridge of your vape is, as the name suggests, turned to vapor rather than steam. This does away with lots of the negative health effects of smoking.

On top of which, you have all the benefits of vaping to enjoy. It’s well worth trying out if you haven’t already. You can even buy cost-effective disposable vapes that let you try out your favorite strain of cannabis in vape form without further commitment.


3) Opting for a low-THC strain

It’s important to remember that all of the effects of cannabis – positive, as well as any negative – are created by the roughly 120 different cannabinoids that can be found in the cannabis plant.

Cannabinoids are a type of organic compound. Your body creates its own endocannabinoids as part of its normal processes. The cannabinoids found in cannabis are phytocannabinoids (plant cannabinoids) that, when you take them into your body, can cause all kinds of effects on those same processes. This can alter things like your mood, appetite, sleep cycle, or the way you experience pain.

It’s also important to note that different strains of cannabis are known to cause different effects (sleepiness as opposed to alertness, for example) precisely because they contain different quantities of these different cannabinoids.

Understanding these facts means that any potentially harmful effects caused by smoking large quantities of weed on a daily basis could be reduced by choosing strains of cannabis that contain lower quantities of cannabinoids such as THC.

Ask your local budtender for some recommendations as to the strains which contain lower levels of THC. It’s worth bearing in mind that you could combine a lower-THC strain with a non-smoking alternative consumption method like a vape. Especially as high-quality vape cartridges are often strain-specific.

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Does weed destroy brain cells? The takeaway

Despite what War on Drugs campaigns of yesteryear might have you believe, weed does not destroy brain cells. At lower doses, studies even seem to show THC and other cannabinoids may be beneficial for the health of your brain, stimulating processes like anti-oxidation to improve brain function.

But, like many things in life, problems occur when you start to go beyond moderation. Chronic cannabis use seems to be associated with having less grey matter in important regions of the brain.

This isn’t weed killing brain cells. Yet it’s certainly a sign that heavy daily use of marijuana is probably best avoided. This is especially true if you are younger than 22 years old and have a brain that isn’t fully formed yet.

This means that taking steps towards moderating your use of cannabis can be a smart move if you are a heavy, regular user. You might try slowly reducing your overall consumption levels, swapping your joint for a vape, or choosing a lower-THC strain as potential ways to help you do this.

Because, as we’ve learned, while the histrionic drug “education” campaigns of forty years ago were pretty nonsensical and weed does not kill brain cells, you still want to be aiming for moderation in your cannabis consumption if you want to stay happy and healthy.

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