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Do any supplements help cannabis withdrawal?

Not clearly. NAC (N-acetylcysteine), the most tested supplement, was judged on clean urine tests rather than on how withdrawal felt, and only one of three trials, 610 people in all, found a benefit. Grade B for no clear benefit. Counseling that pairs cognitive behavioral therapy with motivational enhancement has better support. Symptoms usually peak in the first week. With thoughts of self-harm, get help now.

Last reviewed

How we grade evidenceEditorial policy

What the studies found

  • Grade B. NAC and quitting: mixed, and withdrawal itself wasn't the target. The trials counted weekly urine tests free of cannabis. With a rewards-for-clean-tests program, 116 people aged 15 to 21 had better odds of clean tests on NAC than on placebo over 8 weeks (odds ratio 2.4). Adults (302 people, 12 weeks) saw no difference even with the same rewards program, and nor did 192 people aged 14 to 21 who took it without the rewards program. (Gray 2012; Gray 2017; Gray 2025)
  • Grade B. No medicine or supplement is approved for this. A 2025 Cochrane review found NAC did not raise quit rates over placebo (2 trials, 270 people, moderate certainty) and called every option tested experimental. We found no human trials of melatonin, magnesium, omega-3 or herbs for withdrawal symptoms. (Spiga 2025)
  • Grade C. CBD (cannabidiol): one trial, a small withdrawal signal. In 82 adults trying to quit, 4 weeks of CBD capsules cut cannabis use compared with placebo; in the full report, the highest dose also lowered withdrawal scores a little, while a middle dose made sleep worse. The FDA says CBD can't legally be sold as a dietary supplement (FDA). (Freeman 2020)

Who should be careful

  • In a crisis, or with thoughts of suicide, dial or text 988 (US) or your emergency number.
  • If you also live with depression, bipolar disorder, psychosis or another drug or alcohol problem, plan the stop with a clinician; some people are safer stopping in a clinic or hospital. Symptoms tend to start 24 to 48 hours after the last use and are worst from day 2 to day 6 (Connor 2022).
  • NAC caused more stomach and gut upsets than placebo in the 2025 youth trial (Gray 2025). No interaction studies of NAC in this setting were found.
  • The FDA warns that CBD can injure the liver, can interact with other medicines, and adds to drowsiness with alcohol or sedatives (FDA).
  • Prescription drugs such as gabapentin have been tested in small trials (Mason 2012). They are prescription options a clinician may discuss, not something to take on your own.
  • If you are pregnant, breastfeeding or under 18, ask a clinician first.

Try first

  • Counseling. Cognitive behavioral therapy (CBT), motivational enhancement therapy and the two combined had the most consistent evidence for cutting how often people used, and programs of more than 4 sessions over more than a month did better than brief ones (Gates 2016).
  • Rewards for clean urine tests (contingency management): 5 of 6 studies supported adding them to counseling (Gates 2016).
  • Move for sleep. During a week of inpatient withdrawal, daily cycling lengthened sleep measured by a wrist sensor compared with stretching (31 people), though in the full trial of 46 people it did not ease withdrawal or craving more than stretching (McCartney 2021; Mills 2026).

Sources

  1. Gray KM, et al. A double-blind randomized controlled trial of N-acetylcysteine in cannabis-dependent adolescents. Am J Psychiatry. 2012. PubMed 22706327 · doi:10.1176/appi.ajp.2012.12010055
  2. Gray KM, et al. A randomized placebo-controlled trial of N-acetylcysteine for cannabis use disorder in adults. Drug Alcohol Depend. 2017. PubMed 28623823 · doi:10.1016/j.drugalcdep.2017.04.020
  3. Gray KM, et al. N-acetylcysteine for youth cannabis use disorder: randomized controlled trial main findings. Neuropsychopharmacology. 2025. PubMed 39910268 · doi:10.1038/s41386-025-02061-y
  4. Spiga F, et al. Pharmacotherapies for cannabis use disorder. Cochrane Database Syst Rev. 2025. PubMed 41025421 · doi:10.1002/14651858.CD008940.pub4
  5. Freeman TP, et al. Cannabidiol for the treatment of cannabis use disorder: a phase 2a, double-blind, placebo-controlled, randomised, adaptive Bayesian trial. Lancet Psychiatry. 2020. PubMed 32735782 · doi:10.1016/S2215-0366(20)30290-X
  6. Connor JP, et al. Clinical management of cannabis withdrawal. Addiction. 2022. PubMed 34791767 · doi:10.1111/add.15743
  7. Mason BJ, et al. A proof-of-concept randomized controlled study of gabapentin: effects on cannabis use, withdrawal and executive function deficits in cannabis-dependent adults. Neuropsychopharmacology. 2012. PubMed 22373942 · doi:10.1038/npp.2012.14
  8. Gates PJ, et al. Psychosocial interventions for cannabis use disorder. Cochrane Database Syst Rev. 2016. PubMed 27149547 · doi:10.1002/14651858.CD005336.pub4
  9. McCartney D, et al. The effect of daily aerobic cycling exercise on sleep quality during inpatient cannabis withdrawal: A randomised controlled trial. J Sleep Res. 2021. PubMed 33078435 · doi:10.1111/jsr.13211
  10. Mills L, et al. The effect of daily aerobic cycling exercise on cannabis withdrawal: An inpatient randomised controlled trial. Sci Rep. 2026. PubMed 41708741 · doi:10.1038/s41598-026-40468-9