With marijuana legalized in an increasing number of states, experts continue to explore its potential benefits, side effects, and interactions with other substances.

The interactions between caffeine and marijuana aren’t totally clear yet. Still, you don’t have to look too hard to find products that already mix caffeine with two key compounds of marijuana, CBD and THC.

Read on to learn more about how caffeine can interact with marijuana and the potential side effects and risks of combining the two.

Do they counteract each other?

Research on the interaction between caffeine and marijuana is still in the early stages, but so far, it seems that consuming the two together may produce different effects than using them separately.

Caffeine generally acts as a stimulant, while marijuana can act as either a stimulant or a depressant. In other words, using caffeine tends to energize most people. The effects of marijuana can vary, but many people use it to feel more relaxed.

It may seem possible, then, that caffeine might cancel out the effects of marijuana, or vice versa. For example, maybe smoking a little weed could help counteract coffee jitters. But so far, there’s no evidence to support that the two counteract each other in any way.

There’s no denying that coffee and cannabis are both popular. What’s perhaps less clear is how coffee and cannabis consumption overlap, but with the rise of infused coffee products, it’s safe to say pairing coffee with cannabis is pretty common.

Personally, I’ve consumed coffee and cannabis almost daily for nearly a decade and they both enrich my life. Still, mixing them harmoniously has been a journey for me. Initially, I found the pairing unsettling: The taste of my pipe ruined the taste of my coffee, and I became unbearably jittery when I smoked weed with my morning java.

I thought mixing marijuana and coffee was the quickest way to ruin my morning until I tried vaping, at which point I had a completely different experience: an energized wake and bake with no nasty aftertaste or unpleasant side effects. When I quit inhalants and switched to tinctures and edibles only, I discovered that what works best for me is consuming cannabis immediately after finishing my coffee and a small breakfast or right after drinking my first two cups of coffee.

Clearly, I’ve got my cannabis and coffee routine down, but everyone’s body is different. Let’s take a look at how these two substances affect the body and hear from some experts on cannabis and health.

How coffee affects the endocannabinoid system

A 2018 study in the Journal of Internal Medicine looked at different metabolites—substances created when the body metabolizes food, drugs, and other substances—in the urine of coffee drinkers. Subjects abstained from coffee for one month, consumed four cups daily the next month, and then consumed eight cups daily for one month after that.

The study found that there was a reduction in metabolites of the endocannabinoid system (ECS) with increased coffee consumption, meaning the ECS began metabolizing less and less as study participants upped their coffee intake.

“We can infer from this finding that coffee, and I would speculate more specifically caffeine, can slow down the endocannabinoid system,” said Dr. Shawn Meirovici, ND, naturopathic doctor and cannabis specialist.

“Caffeine is a stimulator of nerve activity … and endocannabinoids are inhibitors of nerve activity. It would seem that coffee/caffeine may decrease this inhibitory activity and therefore may alter the calming [effect] of our endocannabinoid system, making it harder for the body to chill out,” said Dr. Meirovici.

In other words, according to Dr. Meirovici, the study results suggest that coffee or caffeine may actually prevent the ECS from metabolizing at the rate it normally would, making it harder for you to relax.

What are the effects of mixing them?

While there’s no evidence to suggest that marijuana and caffeine simply cancel each other out, two animal studies suggest that mixing the two may enhance some of marijuana’s effects.

A different ‘high’

A 2014 studyTrusted Source looked at squirrel monkeys who had been given THC, the compound in marijuana that produces the high. The monkeys had the option to keep receiving more THC.

Researchers then gave them different doses of MSX-3, which produces effects similar to those of caffeine. When given low doses of MSX-3, the monkeys gave themselves less THC. But at high doses, the monkeys gave themselves more THC.

This suggests that low levels of caffeine may enhance your high so you don’t use as much. But high levels of caffeine could affect your high in the opposite way, leading you to use more marijuana.

More research as needed, as this small study was conducted only on animals, not humans.

Memory impairment

Caffeine helps many people feel more alert. You might drink coffee, tea, or energy drinks every morning to help you wake up, or just to help increase your concentration when you feel tired or less focused than usual.

Some people also find caffeine helps improve working memory. Marijuana, on the other hand, is known for its less desirable effect on memory. Again, you’d think the two would balance each other out, but that doesn’t seem to be the case.

A 2012 studyTrusted Source looking at how a combination of caffeine and THC affected memory in rats. The results suggest that a combination of caffeine and a low dose of THC seemed to impair working memory more than a higher dose of THC would on its own.

Remember, this study was only done using rats, so its unclear how these results translate in humans. Still, it does suggest that caffeine may increase the effects of THC.

Are there any immediate risks?

So far, there haven’t been any reported cases of extreme risks or side effects of combining caffeine and marijuana. But that doesn’t mean they don’t exist.

Plus, people can have varying reactions to both caffeine and marijuana. If you do try mixing the two, make sure you first understand how your body reacts to each one individually. If you’re sensitive to marijuana, for example, combining it with caffeine might result in an unpleasantly strong high.

If you do decide to mix marijauna and caffeine, follow these tips to help you avoid a bad reaction:

• Start small. Start with small amounts of both, less than you would typically consume of each individually.
• Go slow. Give your body plenty of time (at least 30 minutes) to adjust to the combination before having more of either substance.
• Pay attention to usage. It might sound like overkill, but it’s easy to lose track of how much caffeine or marijuana you’ve had, especially when mixing the two.

There are serious side effects that can come from ingesting very high doses of caffeine, from high blood pressure to rapid heart rate. There have also been deaths related to ingesting large amounts of caffeine, though researchers notedTrusted Source that the deceased took caffeine pills or powder, not caffeinated drinks.

Above all, make sure to listen to your body and mind. If you experience unusual symptoms after mixing the two, reach out to a healthcare provider for guidance. You likely aren’t in any great danger, but the combination of caffeine’s heart-racing effects and marijuana’s tendency to cause anxiety in some people can be a recipe for panic.

What about long-term effects?

It’s unclear if mixing caffeine and marijuana has any long-term effects. But remember, an animal study found that consuming THC with large amounts of a substance that mimics the effects of caffeine may minimize marijuana’s effects. This might lead you to use more marijuana than you usually would.

Over time, repeatedly using increasing amounts of marijuana may lead to developing a substance use disorder.

If you regularly mix caffeine and marijuana, keep an eye out for these signs of a substance use disorder:

• developing a tolerance to marijuana, requiring you to use more to achieve the same effects
• continuing to use marijuana despite not wanting to or encountering bad effects
• spending a lot of time thinking about using marijuana
• paying close attention to maintaining a constant supply of marijuana
• missing out on important work or school events due to marijuana use