Can You Overdose On Cannabis?

Drugs are powerful things, and it’s important to know what you’re dealing with before you take any substance. Weed is no exception. But can you overdose on marijuana? Read on to discover how much weed you'd need to take to overdose (spoiler: more than you can possibly take) and the science behind the body’s wonderful, natural defence mechanisms against getting too blazed.

What do we mean by overdose?

An overdose is the average dose at which the toxicity of a drug will kill the majority (over 50%) of people. In reality, this dose is usually determined by scientists based on animal studies and the human effect is then estimated based on scientific formulae. The good news: no matter how hard scientists have tried, it has proven literally impossible to kill any animals through marijuana toxicity. The bad news: there are some people whose job it is to try to kill animals with weed (they are called toxicologists).

An overdose need not always be fatal. Many people will experience a drug overdose and recover, although the experience might be extremely dangerous. Overdosing, or OD-ing, is a term that is often used to encompass more than its medical definition. As stated, a medical overdose occurs when the drug's toxicity would kill over 50% of people. Fatality can occur through heart or breathing problems, neurological effects, or something less common. In common usage, though, the term overdose is often used to describe an experience where so much of a drug is taken that it has very unpleasant effects.

With all that said, when it comes to cannabis, the term overdose should never apply in real life.

Is there such a thing as a cannabis overdose?

That’s not to say there is no overdose level for cannabis, only that it is extremely high. In practicality, it would likely be impossible to die through excess cannabis use alone. If you search online, you’ll find plenty of resources discussing cases of so-called cannabis overdose. But if we’re being exact, it is probably wrong to call these cases overdoses. The reason: although the THC might have caused extremely unpleasant effects, it would not have reached toxic levels in the body, and therefore does not actually cause a physical danger—though it can certainly cause serious adverse psychological effects.

In animal studies, the lowest known overdose is 40mg of pure THC per kg of body weight—the highest is 130mg/kg. It’s important to bear in mind that these studies used THC extract that was administered intravenously (injected)—a much more potent method of consumption that is never used for cannabis in the real world.

Other research suggests that, as a rough estimate based on animal studies, the amount of marijuana one would need to consume in order for a fatal overdose to occur is about 680kg in 15 minutes. Though we’re not advising it, any person who manages to achieve this would go down in history as a legend, if not a little over-enthusiastic about getting high. Hopefully, that puts it in perspective a little. Even if you wanted to, could you really afford to overdose on marijuana?

What happens when you smoke or eat too much marijuana?

Although you will not lethally overdose on marijuana, that’s not to say you can’t smoke too much and have a bad time. Generally, the effects of cannabis are highly enjoyable, but negative experiences can occur. We’ve all been there, and it’s not pleasant. At the moderate end of the spectrum, excess marijuana use can cause increased heart rate, sweating, nausea, dizziness, disorientation, and dry mouth (which can be horrible!).

At its worst, expect to be very sick. Not unlike getting too drunk, smoking too much marijuana can make you very unwell. Though, unlike drinking alcohol, excess marijuana use will not do any long-term physical damage. For those who don’t know, the term for getting too stoned is “whiteying”. In its verb form: "to whitey". You may also hear the term “greening out” to describe this phenomenon.

Are there any long-term after-effects of taking too much cannabis?

Weed hangovers have not really been studied by scientists, so the evidence is mostly anecdotal. Nonetheless, there are enough stories about it to suggest that, for many people, they do exist. The symptoms can vary; some people report symptoms similar to alcohol hangovers, while other symptoms seem unique to marijuana use. These range from headaches and lethargy to fogginess and poor memory. Of course, some of these effects are also dependent on whether you smoke your cannabis with or without tobacco.

There is some evidence to suggest that long-term, frequent use of cannabis can have negative physical effects—this is especially true when it is used during adolescence, when the brain is still developing. For example, regular use of cannabis is thought to cause the grey matter in the prefrontal cortex to thin. Scarily, it is not known whether this reverses if usage is stopped, or whether it causes permanent damage. This is the major reason that young people should avoid using cannabis until their brains are fully developed.

It seems that most of the damage caused by smoking cannabis occurs when use is frequent and continuous, rather than if you take too much at once. Using too much in one go may be very uncomfortable, but it shouldn’t do any lasting damage.

Is there a difference between smoking, vaping, or eating too much marijuana?

Consuming edible cannabis products is far more likely to cause prolonged after-effects than vaping or smoking weed. Inhaled (smoked or vaped) marijuana tends to be metabolised fairly quickly in the body, whereas edible marijuana is processed much more slowly. Therefore, the likelihood of greening out is much greater if you consume edibles.

At the same time, the effects of overdoing it are different too, depending on the method of ingestion. If you smoke too much marijuana, you can expect to feel unwell fairly quickly, and to recover equally quickly. Usually, fresh air and a glass of water are enough to bring you back.

Not so with edibles. Due to the increased potency and duration of this method, the effects of overdoing it can be much more distressing. While the effects often build up slowly, you can find yourself almost paralysed and unable to do very much at all if you eat too much marijuana.

What’s more, there’s no quick way out. It’s one of those times in life where you just have to ride the wave. For those interested, when marijuana is digested, delta-9-THC is converted to 11-hydroxy-THC, which hits harder and lasts longer.

The solution? Start slowly and be patient! Wait until your edibles have kicked in before eating more. Waiting half an hour more to get high is preferable to being curled up on the bathroom floor for six hours. Don't say we didn't warn you.

How much cannabis is “too much”?

As mentioned, if you’re looking to overdose, then “too much” cannabis really is too much—you wouldn’t be able to lift it, let alone pack a rolling paper with it.

That being said, you can take too much of a drug without overdosing. So a sensible answer to how much is too much would be: it depends. Your body weight, general constitution, tolerance levels, and consumption method all play a role in how much THC affects you on any given day.

For a smaller person with little to no experience with cannabis, then a few tokes on a spliff or joint is going to be ample to have a good time. 5–10mg of THC is considered to be a low to moderate dose, suitable for novice users. If you take more than this, then you might well find you have an unpleasant experience. But don’t worry, you’re not overdosing and no permanent harm will come to you!

Frequent users can handle much more and will become aware of their tolerance over time. So saying what constitutes “too much” is challenging. But here’s something to ponder on: just because you can consume a lot of cannabis, does that mean you should?

Even if you have an epic tolerance and can handle a lot of weed, that doesn’t mean that you’re not still taking too much. Heavy, frequent use is known to have adverse physical and psychological effects. So a better question might be, how often is “too often”?

Can you overdose on CBD?

There is no evidence to suggest a fatal overdose is possible with CBD. In fact, preliminary studies have found humans to tolerate doses of up to 1,500mg of CBD per day, with no observed adverse effects. This, of course, is a much higher dose than one person would take anyway. Still, that’s not to say CBD can’t cause an overdose, but it’s likely one would need to consume a similarly ludicrous amount to the THC overdose threshold mentioned above.

Nonetheless, it is possible to experience unwanted side effects, such as lethargy and upset stomach, from CBD. Much like with THC, use this cannabinoid with care and respect.

With all that said, animal studies suggest that CBD can have some adverse health effects when administered at very high doses. These include developmental toxicity, embryo-fetal mortality, central nervous system inhibition and neurotoxicity, hepatocellular injuries, spermatogenesis reduction, organ weight alterations, male reproductive system alterations, and hypotension.

What to do when you’ve consumed too much cannabis

There are a few things you can do if you feel like you’ve consumed too much cannabis:

• Relax: As you know by now, nobody has ever fatally overdosed from cannabis use. In a few hours, you’ll be fine. Try not to worry about what is to come, and stay in the here and now.

• Drink something refreshing: Water is an all-time favourite. However, maybe something sweet and bubbly might hit the spot. In short, treat yourself and refresh yourself.

• Take a walk outside: This one cannot be stressed enough—fresh air and movement are a fantastic way to relax and shake that funk (if you can get off the sofa!). Stay in a known area so you feel safe and comfortable.

• Talk to people: If you’re with people, let them know you’re feeling too high. That way, you can laugh about it, instead of incessantly thinking about it. It's easier not to panic when familiar people are talking to you in a gentle and calming manner.

• Take some CBD: Taking more cannabis might not jump out as the solution, but CBD may counteract some of the effects of THC. Just make sure you don’t smoke the wrong bud! Perhaps just carry a bottle of CBD oil with you and take a few drops if you feel overwhelmed.

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  What to do when you're too high on cannabis

How your body protects itself from overdosing on marijuana

The body is a wonderful thing, and it even has an inbuilt mechanism to stop us from getting too stoned. This is how it works: THC binds to CB1 receptors in the brain. These receptors are partially responsible for the regulation of the body's endocannabinoid system. When the CB1 receptor is activated, it triggers the production of pregnenolone (an inactive precursor of all steroid hormones). What does pregnenolone do? It counteracts the effects of THC. The more weed you smoke, the more your body will defend against it.

In scientific terms, this is known as a paracrine, or autocrine, loop. It essentially protects the CB1 receptors from overstimulation. As THC stimulates the CB1 receptors, the production of pregnenolone is exponentially increased. This is why it is almost impossible to overdose on marijuana. Another reason is that a high dose of THC will knock you out, and you will become unconscious. However, breathing, heartbeat, and other major bodily functions are not affected, unlike with opioids, which depress the breathing reflex and can prove fatal.

Should you worry about a cannabis overdose?

No. If you find yourself too stoned and you’re worrying about dying from a marijuana overdose, you can expel that thought from your mind. It’s not going to happen. Don’t take this as your cue to smoke stupid amounts of weed, though. Although it is a pretty safe drug, it can have adverse mental effects if used inappropriately, and these can be just as harmful as the physical ones. Also, being high may get you injured by a car accident, a fall, or getting in other stupid situations—so be cautious.

As a rule of thumb, if you’re enjoying yourself, you’re probably good!

Cannabis: Everything in moderation

In the short term, cannabis is a safe drug for the majority of adult users. A minority can experience adverse psychological effects immediately, but most will only experience these with continuous, frequent, and heavy use. The takeaway from this article is that you will not overdose on cannabis, so if you’re freaking out right now, you can rest easy knowing that it will pass, and you’ll be okay.

But don’t think that this means cannabis is totally safe and harmless. Just because you can’t overdose doesn’t mean it can’t harm you. In fact, cannabis’ good safety profile is one of its dangers; you can take it all the time and still get on with life, and this in itself can cause many problems further down the line.

So don’t take too much, and don't do it too frequently. Follow those rules, and you should have a great time.

Max Sargent

Max has been writing for over a decade, and has come into cannabis and psychedelic journalism in the last few years. Writing for companies such as Zamnesia, Royal Queen Seeds, Cannaconnection, Gorilla Seeds, MushMagic and more, he has experience in a broad spectrum of the industry.

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