Does CBD Help With Weed Withdrawal? What Trials Show

Does CBD help with weed withdrawal? The honest answer is: possibly a little, at a high dose, in one small trial. A 2020 randomised study found that 800mg of pharmaceutical CBD a day lowered withdrawal scores modestly compared with placebo, while a 400mg dose did not. No trial has tested the CBD oils, gummies or vapes you can buy in a shop, and those products have their own problems, including undeclared THC.

That is not nothing. But it is a long way from "CBD treats withdrawal", which is how it is often sold. Below is what the trials found, what they did not, and what to weigh before you try it.

What the CBD trial actually found

The main study is a phase 2a trial published in The Lancet Psychiatry in 2020. It enrolled 82 adults with cannabis use disorder who wanted to quit, gave them CBD or placebo daily for four weeks, and added a short course of motivational talking therapy for everyone.

The trial started with doses of 200mg, 400mg and 800mg. The 200mg arm was dropped part-way through as ineffective. The results for the rest were mixed:

So the dose that helped with cutting down was not the dose that helped with withdrawal, and neither effect was large. On the Cannabis Withdrawal Scale, the 800mg group scored about 1.3 points lower than placebo on average during treatment.

The authors are careful about what this means. They write that the trial "was not designed to estimate efficacy" — it was built to find which doses were worth testing in a bigger study — and that its secondary outcomes, which include withdrawal, were mixed. That is the right way to read it: a promising early signal, not a proven treatment.

Before this trial, the evidence was a single case report of a 19-year-old woman who took CBD for 10 days and reported no significant withdrawal. One person is not evidence of anything for anyone else.

CBD combined with THC: the nabiximols trials

Most of the medication research on cannabis withdrawal has not used CBD alone. It has used nabiximols, a prescription mouth spray that contains both THC and CBD. The idea is the same as nicotine patches: replace the drug with a controlled dose and step it down.

In a six-day inpatient trial of 51 people, nabiximols significantly reduced overall withdrawal severity, including irritability, depression and cravings, compared with placebo. But once the medication stopped, placebo was just as good at producing long-term reductions in cannabis use.

A larger 12-week trial of 128 people found that nabiximols meant significantly fewer days of illicit cannabis use than placebo — about 35 days against 53 over the trial. Yet on withdrawal and cravings, both groups improved to a similar degree.

Two things to take from this. First, the withdrawal benefit came from a product that contains THC, which is a replacement strategy, not a cannabis-free one. Second, it does not tell you much about CBD on its own. If gradually stepping down is what appeals to you, tapering off weed covers how to do that with what you already use.

What the systematic review concluded

A 2019 Cochrane review of medications for cannabis dependence pooled the trials available at the time. Its conclusion was blunt: there is incomplete evidence for all of the medications investigated, and for many outcomes the quality of the evidence was low or very low.

On THC-based preparations such as nabiximols, the reviewers said they should be considered "still experimental", with some positive effects on withdrawal and craving. The review came out before the 2020 CBD trial, so it contains no trial of CBD alone.

The US position matches. NIDA states that there are currently no FDA-approved medications for cannabis use disorder or for medically assisted withdrawal, though research is ongoing.

The problem with the CBD you can actually buy

Even if the trial result holds up, it came from a pharmaceutical-grade product at a measured dose. What is on the shelf is a different thing.

A study in JAMA tested 84 CBD products sold online and found that only about 31% were accurately labelled for CBD content. Around 43% contained more CBD than the label said, and 26% contained less. More importantly for anyone quitting, THC was detected in 18 of the 84 products — about one in five.

That matters more than it sounds. If you are trying to stop, a CBD product with undeclared THC can quietly keep your tolerance up, keep the habit loop running, and make the eventual withdrawal longer. You would have no way of knowing.

The FDA says the same thing in plainer terms. It has approved only one CBD product, a prescription drug for specific seizure disorders, and notes that many products it tested did not contain the levels of CBD they claimed, with some investigated for contaminants including THC.

Doses matter too. The dose that reduced withdrawal in the trial was 800mg a day. Many consumer products contain a small fraction of that per serving, so a few drops of oil is not a replication of the study.

Side effects and interactions

CBD is often described as harmless. It is not quite that. According to the FDA, CBD can cause liver injury and can affect how other medications work, and combining it with alcohol or sedating drugs — the kind used for anxiety, panic or sleep — raises the risk of drowsiness and injury.

The National Center for Complementary and Integrative Health lists diarrhoea, sleepiness, abnormal liver function tests and drug interactions as side effects that appear to come from CBD itself rather than from contaminants.

That makes CBD a poor fit for improvising in the first week of withdrawal, when many people are also reaching for sleep aids, extra alcohol or anxiety medication. If you take any prescription medicine, ask a pharmacist before adding CBD.

What tends to help instead

Most people get through cannabis withdrawal without any medication. It is unpleasant, but it is time-limited: symptoms usually peak in the first week and ease over one to three weeks, as covered in how long weed withdrawal lasts. What helps is mostly unglamorous:

• Talking therapy. Cognitive behavioural therapy has the most consistent evidence for quitting. CBT for quitting weed explains what a course involves, and therapy for cannabis use disorder compares the approaches that have been trialled.
• Protecting sleep. Sleep is usually the symptom that lasts longest. A fixed wake time and no screens in bed do more than most supplements. If nights are the hardest part, see why you cannot sleep after quitting weed.
• Eating on a schedule. Appetite drops early. Small regular meals keep energy and mood steadier.
• A plan for the craving itself. Cravings peak and pass in minutes. Knowing what you will do for those minutes — a walk, a call, a few rounds of slow breathing — beats relying on willpower in the moment.

If you still want to try CBD

It is your decision, and some people will try it regardless of what the trials say. If you do, a few things reduce the risk:

1. Talk to a doctor or pharmacist first, especially if you take other medications, drink, or have liver problems.
2. Choose a product with a third-party certificate of analysis that shows its CBD and THC content, and check that the batch number matches.
3. Avoid anything that contains THC, including "full-spectrum" products, which can contain small amounts.
4. Treat it as a short-term aid, not a replacement habit. Swapping one daily cannabinoid ritual for another keeps the routine of reaching for something intact.
5. Keep counting your days from your last THC, not from when you stopped everything. The streak that matters is the one your tolerance is tracking.

Be honest with yourself about the purpose. If CBD is a way of staying close to cannabis while telling yourself you have quit, it will probably make the eventual stop harder.

When to get medical help

Withdrawal from cannabis alone is rarely dangerous, but some situations need a clinician rather than an over-the-counter product. Get help if withdrawal is severe or not improving after a few weeks, if you also use alcohol, benzodiazepines or opioids, if you are pregnant, if you have repeated vomiting, or if you have a mental health condition that is getting worse.

In the US, SAMHSA's National Helpline is free, confidential and open 24/7 at 1-800-662-4357. If you are in immediate danger or thinking about harming yourself, call your local emergency number.

The short version

• One small 2020 trial found that 800mg of pharmaceutical CBD a day modestly lowered withdrawal scores. The 400mg dose did not.
• The trial was built to find doses, not to prove CBD works. A larger study is still needed.
• THC-plus-CBD spray reduced withdrawal in trials, but it contains THC and is a replacement approach.
• There are no FDA-approved medications for cannabis withdrawal.
• About one in five CBD products tested contained THC, which can undermine a quit attempt.

Sources

• Cannabidiol for the treatment of cannabis use disorder: a phase 2a, double-blind, placebo-controlled, randomised, adaptive Bayesian trial — The Lancet Psychiatry, via PMC — doses, withdrawal and abstinence outcomes.
• Cannabidiol for the treatment of cannabis withdrawal syndrome: a case report — Journal of Clinical Pharmacy and Therapeutics, PubMed — the single case report.
• Nabiximols as an agonist replacement therapy during cannabis withdrawal — JAMA Psychiatry, PubMed — six-day inpatient trial.
• Nabiximols for the Treatment of Cannabis Dependence — JAMA Internal Medicine, via PMC — 12-week outpatient trial.
• Pharmacotherapies for cannabis dependence — Cochrane Database of Systematic Reviews, via PMC — quality of the evidence for medications.
• Labeling Accuracy of Cannabidiol Extracts Sold Online — JAMA, via PMC — CBD and THC content of consumer products.
• Cannabis (Marijuana) — NIDA — no FDA-approved medications for withdrawal.
• What You Need to Know About Products Containing Cannabis or CBD — FDA — approval status, safety and labelling.
• Cannabis (Marijuana) and Cannabinoids: What You Need To Know — NCCIH — side effects of CBD.
• SAMHSA National Helpline — free, confidential support at 1-800-662-4357.