Avoid

⛔ Best avoided

Phenibut

Also called: beta-phenyl-GABA

A Russian medicine sold online as a supplement.

Why people take it
Anxiety, sleep.
What the evidence says
Not approved as a supplement.
How it is usually taken
Not recommended at any amount; see the warning above.
Be careful
Dependence and dangerous withdrawal.
Medicines it can interact with
Dangerous with alcohol, sedatives and opioids; withdrawal can be severe.

Other avoid

EphedraBitter orangeDMAAComfrey (by mouth)AristolochiaGermanderChaparralPennyroyalLobeliaKratomSARMsProhormonesTianeptine

Common questions

What is Phenibut?

A Russian medicine sold online as a supplement.

Why do people take Phenibut?

Anxiety, sleep.

Does Phenibut work?

Not approved as a supplement.

How much Phenibut do people take?

Not recommended at any amount; see the warning above.

Is Phenibut safe?

Dependence and dangerous withdrawal.

Does Phenibut interact with medicines?

Dangerous with alcohol, sedatives and opioids; withdrawal can be severe.

Sources and further reading

Last reviewed 31 October 2026. Written by Satya Babu.

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For information only, not medical advice. Supplements are not medicines: they are not tested and approved like drugs before they are sold, and they can interact with medicines. Talk to your doctor or pharmacist before you start one, especially if you are pregnant or breastfeeding, take regular medicines, or have kidney, liver or heart disease.