CBD Side Effects: What Adults Should Know Before Trying It

CBD Side Effects: What Adults Should Know Before Trying It

Written by Sarah Miletich

Sarah Miletich, BS Organic Chemistry, MS Cosmetic Science, CEO & Lead Formulator

Short answer: CBD is generally well tolerated in clinical trials, and the side effects that do show up are mostly mild and dose-related. The most-watched one is not drowsiness, it’s liver enzyme elevation, and it matters most at high doses and alongside certain medications.

Here is what the research found, and the part most CBD articles skip: almost all of it was done at doses far above what you’d take from a wellness tincture.

 

 

What the trials actually reported

The best-characterized safety data on CBD comes from the clinical program behind Epidiolex, the prescription cannabidiol medication. The effects reported most consistently:

  • Somnolence and sedation, drowsiness, sluggishness

  • Decreased appetite

  • Diarrhea and other digestive upset

  • Fatigue and malaise

  • Elevated liver transaminases, a blood marker of liver stress

Two features of that list matter more than the list itself.

They are dose-related. Frequency and severity rose with dose. This is why “CBD has side effects” is an incomplete sentence, the question is always at what dose.

Dose is only one part of the safety picture, our CBD safety guide covers side effects, interactions, and other questions to consider before trying CBD.

Trial doses were high. Epidiolex is dosed by body weight, in the range of milligrams per kilogram per day, which puts a typical adult well into the hundreds of milligrams daily. A wellness tincture serving is usually a small fraction of that.

That cuts two ways, and you should hear both halves:

The high-dose data is reassuring about the consumer dose range, because most consumers never approach the doses where these effects clustered.

It is also the case that the consumer dose range is the range with the least rigorous long-term data behind it. “Studied at 20 mg/kg/day” is not the same as “studied at 25 mg/day for three years.” Anyone who tells you the low-dose long-term safety picture is settled is overstating what exists.

 

 

The one worth taking seriously: liver enzymes

Most CBD side effects are the kind you notice and can respond to. Liver enzyme elevation is not, it shows up on a blood test, not in how you feel.

What the prescribing information establishes:

  • CBD can cause dose-related transaminase elevations.

  • Risk is higher when transaminases are already elevated at baseline.

  • Risk is higher alongside valproate.

For most healthy adults at consumer servings, this is unlikely to be relevant. It becomes relevant if you have existing liver disease, if your liver enzymes are already elevated, if you take medications that stress the liver, or if you use high doses over an extended period.

Signals worth calling a clinician about: unusual or persistent fatigue, loss of appetite, nausea, abdominal pain (particularly upper right), dark urine, or yellowing of the skin or eyes. These are not reasons to panic, they are reasons to make a phone call rather than wait and see.

If you fall into any of the higher-risk groups above, ask your clinician whether a baseline liver panel makes sense before you start.

 

 

The common, milder effects

Drowsiness

The most frequently reported effect. For someone taking a CBD and CBN blend at night, that may be the point. For someone taking CBD during a workday, it isn’t.

Practical response: if CBD makes you sleepy, move it to the evening before you conclude it doesn’t work for you. Timing is the first variable to change, not dose. And see our note on driving.

Digestive upset

Diarrhea and stomach discomfort turn up consistently. Part of this may be the carrier oil rather than the CBD itself, our tinctures use MCT oil, and MCT oil can cause digestive upset in some people, particularly on an empty stomach.

Practical response: take it with food, and reduce the serving size before abandoning it entirely.

Appetite changes

Usually reported as decreased appetite. Notable mainly because it runs counter to the cultural assumption that anything cannabis-adjacent increases appetite, that association is with THC, not CBD. The difference between the two →

Dry mouth

Commonly reported, generally minor.

 

 

Reducing your odds of a bad experience

  1. Start low. Most unpleasant first experiences with CBD are dose problems, not CBD problems. Our dosage guide walks through starting points →

  2. Change one variable at a time. Dose, timing, or product, not all three in the same week.

  3. Take it with food. Reduces digestive upset for many people.

  4. Give it a fair window. A few days at a steady serving tells you more than one dose.

  5. Know what’s in the bottle. Some “side effects” are contaminants, or an ingredient other than CBD. A COA can provide information about relevant testing panels and results. See every Proof COA →

  6. Stop and ask if something feels wrong. A wellness product is not worth pushing through a symptom for.

 

 

Frequently asked questions

What are the most common CBD side effects? Drowsiness, decreased appetite, diarrhea, fatigue, and dry mouth. In clinical trials these were generally mild and dose-related.

Can CBD damage your liver? Clinical trials found dose-related liver enzyme elevations, with risk higher at high doses, alongside valproate, and in people whose transaminases were already elevated. At consumer serving sizes in healthy adults this is unlikely, but it is the reason people with liver conditions should speak to a clinician first.

Do CBD side effects go away? Many are dose-related and ease when the serving is reduced or the timing changes. Anything persistent or worsening warrants a clinician’s opinion rather than experimentation.

Can you take too much CBD? CBD does not carry the overdose profile associated with some substances, but more is not better, side effects rise with dose, which is the practical ceiling.

Does CBD have side effects in pets? Yes, and species matters. Start with your veterinarian and our pet CBD guide.

 

 

Related reading

  • CBD Safety Guide: The Questions Worth Asking Before You Start 

  • Can You Take CBD With Prescription Medication?

  • CBD Dosage Guide: How Much Should You Take?

  • Can You Drive After Taking CBD?

 

 

Sources

 

 

This article is for general information and is not medical advice. CBD is not approved by the FDA to diagnose, treat, cure or prevent any disease. Talk to your healthcare provider before using CBD, particularly if you take prescription medication.

Part of our CBD guides: Explore our CBD Learn Hub for practical guides, helpful resources, and answers to common questions.

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