5-alpha-reductase inhibitor (type II)
Finasteride and cannabis (marijuana, THC)
As cannabis becomes legal or decriminalised in more jurisdictions, the practical question of combining it with prescription medication comes up regularly. Finasteride (Finasteride) and cannabis share several pharmacological pathways, and the combination at 1mg is not automatically benign even where both are legal.
How cannabis affects Finasteride
THC and other cannabinoids are metabolised partly by hepatic CYP enzymes, including CYP3A4 — the same pathway used by many 5-alpha-reductase inhibitor (type II) medications. Frequent cannabis use can shift the metabolism of Finasteride mildly. THC also has cardiovascular effects (increased heart rate, blood pressure changes) and central nervous system effects that can stack with Finasteride's side-effect profile.
Practical guidance
Occasional moderate cannabis use is unlikely to cause clinically meaningful problems for most adults on Finasteride at 1mg. Heavy daily use, edibles with high THC content, or cannabis combined with alcohol substantially raise the risk of dizziness, hypotension, impaired judgement and amplified side effects from Finasteride. According to the prescribing information, the full list of recreational substances should be disclosed to the prescriber.
Frequently asked questions
Can I use cannabis while taking Finasteride? ▾
For most adults at 1mg, occasional moderate cannabis is tolerated, but heavy daily use is not advised because of metabolic and additive cardiovascular effects with Finasteride. The safe practice is to mention it to the prescriber.
Does CBD interact with Finasteride? ▾
CBD inhibits several CYP enzymes including CYP3A4, which can raise plasma levels of medications that go through that pathway. For Finasteride specifically, this depends on whether Finasteride uses CYP3A4. Daily high-dose CBD products warrant a pharmacist check.
Products containing Finasteride
More on Finasteride
- With alcoholFinasteride and alcohol — is it safe to drink?
- With foodShould Finasteride be taken with food?
- Side effectsFinasteride side effects: common, rare and warning signs
- Dosage guideFinasteride dosage guide: how much to take and when
- OnsetHow fast does Finasteride start working?
- DurationHow long does Finasteride last?
The information on this website is provided for reference and educational purposes only. It does not replace consultation with a qualified healthcare professional.