Cannabis 101Health

What Are the Side Effects of High-THC Cannabis?

Published on August 4, 2016 · Last updated August 20, 2020

Like virtually all medicines, cannabis can induce its own unique set of side effects. Although not everyone’s experience comes with a side of adverse reactions, it’s worth knowing what you may be at risk for, especially if you’re a new user. Keep in mind, these cannabis side effects are caused by its main psychoactive ingredient, THC (we’ll get to the side effects of other cannabinoids in future articles). Although this list doesn’t include all side effects of THC, it cites the most commonly experienced.

How to Avoid the Unappealing Effects of THC

There are a few ways to help you dodge the not-so enjoyable effects of THC:

  • Try a strain that is high in CBD, like ACDC, Cannatonic, Harlequin, or Canna-Tsu. CBD is not psychoactive in the same way as THC, and it can help curb the side effects of THC for a more relaxed, mellow experience.
  • Start with a very low dose when using high-THC strains. Adverse side effects tend to set in with continued or heavy consumption, so start with just a puff or two and see how you feel. You’d be surprised how much fun you can have with minimal amounts of cannabis.
  • Consider using an oil-filled vape pen if you’re sensitive to smoking or edibles. These allow a great deal of dosing control with mild effects, which has made them incredibly popular choices among newbies and older generations jumping back into cannabis.
  • Start with a 5 mg dose of edibles if you’re unaccustomed to THC. From there, you can slowly and responsibly work your way up in dosage if the effects are mild.
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5 tips to safely dose and enjoy high-THC cannabis edibles
  • Drink lots of water while using cannabis. Hydration is key to avoiding many unpleasant side effects.

Potential Side Effects of High-THC Cannabis Strains

Here’s a breakdown of the potential side effects associated with high-THC cannabis strains.

Paranoia and Anxiety

potential high-thc marijuana side effects: paranoia and anxiety

One of the worst side effects of THC is anxiety and paranoia. Though small amounts of THC are likely to only induce mild paranoia or social anxiety, edibles and large doses can cause exaggerated side effects (just ask the guy who ate an edible and called 911 because he thought he was dying). THC is known to relieve anxiety in smaller doses and increase it in larger; this is due to its biphasic effects, meaning it can have two opposite effects in high doses. Furthermore, some people are genetically predisposed to experience anxiety with cannabis as a result of brain chemistry.

Related
Can CBD undo the anxious side effects of THC?

If you do find yourself susceptible to cannabis’ anxious effects, definitely give some of the above tips a try – CBD strains are amazing anti-anxiety solutions, even after the fact! It also helps to only consume when you’re in a comfortable place, such as at home or with friends.

Dry Mouth

potential high-thc marijuana side effects: dry mouth

Better known as the dreaded “cottonmouth,” high-THC cannabis can also make your mouth drier than the Sahara Desert. Believe it or not, there are cannabinoid receptors in our saliva glands. THC mirrors a naturally occurring chemical called anandamide, which binds to these receptors to decrease saliva production. THC, with its high affinity toward these receptors, exaggerates that effect much to our dismay.

Remember to dose low and keep plenty of water (and maybe some chewing gum) on-hand in the event that cottonmouth strikes.

Dry, Red Eyes

potential high-thc marijuana side effects: red eyes

Not only does THC cause the mouth to dry out, it can also cause dry, red eyes. It’s the classic, telltale giveaway that has made eye drops a natural companion for discreet cannabis consumers. But what causes it, and are eye drops the only cure?

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It may be, in part, due to the fact that smoke can irritate the eyes, but other consumption methods can also cause dry, red eyes. THC is known to lower blood pressure and dilate blood vessels in the eyes, leading to redness. Though less likely, an allergy to cannabis can also cause red eyes.

To counter these side effects, pump the water and stay hydrated. Eye drops can be helpful if your eyes are irritated, but avoid relying on these every time, as some brands can actually cause dryness afterward if used continually.

Hunger and “Munchies”

potential high-thc marijuana side effects: the munchies

Unless you have an underactive appetite, you might consider the munchies a nuisance and side effect of THC. Because it stimulates areas of the brain associated with appetite, THC can jumpstart a fierce hunger that may or may not motivate you to order the entire left side of the Taco Bell menu.

Curb this side effect with high-CBD or high-THCV strains.

Related
The Science of Munchies: Why Does Cannabis Stimulate Your Appetite?

Sleepiness and Lethargy

potential high-thc marijuana side effects: sleepiness and lethargy

Once again, this “side effect” is seen by some as a therapeutic benefit as THC fights insomnia and promotes rest. However, if you’re looking to stay active while using cannabis, bear in mind that some strains can induce naps, lethargy, or an early night’s sleep.

Indica strains have long been associated with sedative effects, so we recommend sativa or high-CBD strains for daytime use. You may also consider trying a cannabis-infused coffee or tea, or pairing them to help lift out the lethargy.

Related
Marijuana & Sleep: 9 Things to Know About Your Herbal Nightcap

Impaired Memory

potential high-thc marijuana side effects: impaired memory

Although memory impairment tends to be less of a problem for those well-accustomed to new consumers, it can be an annoying affliction to many. Luckily, memory impairment associated with cannabis appears to be temporary, but even short-term effects can get in the way of a productive afternoon and cognitive tasks.

Once again, high-CBD strains are a wonderful alternative for anyone looking to keep their memory and cognition intact. Supplements like gingko biloba and B vitamins may be helpful in countering these side effects, but your best bet for maintaining cognition is dosing low and slow.

You may experience a number of other side effects with cannabis such as headaches, dizziness, and respiratory difficulties, although these are less common. It’s always a good idea to communicate your cannabis consumption with your doctor in case it interacts with another medication you are taking. Because its side effects tend to be mild, many patients prefer it to other medications, but familiarizing yourself with any and all risks is the best way to ensure a good experience for yourself and the loved ones you’re enjoying it with.

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Bailey Rahn
Bailey Rahn
Bailey is a senior content manager at Leafly, specializing in strains and health. She's spent 7+ years researching cannabis products, spreading patients’ stories, and exploring healthy ways of integrating cannabis into daily life.
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