Allyl Mercaptan

PhytochemicalOrganosulfur

What is it

Allyl mercaptan (2-propene-1-thiol) is a volatile organosulfur compound formed from garlic and other Allium species when alliin-derived precursors break down. It is one of the metabolites responsible for 'garlic breath' after eating garlic.

Evidence for 1 use

AI-assisted evidence assessment — talk to your doctor before relying on any single supplement.

Garlic-related cardiovascular and metabolic benefits

Mixed Evidence

While whole garlic and certain garlic preparations have evidence for modest cardiovascular benefits, isolating allyl mercaptan as the active component has not been validated in human trials.

How it works

Allyl mercaptan is a sulfur-containing thiol produced enzymatically and through gut metabolism from garlic-derived precursors such as allicin and diallyl disulfide. It is rapidly exhaled via the lungs, accounting for the characteristic odor on the breath hours after consumption. In vitro it has shown antioxidant activity and inhibition of certain histone deacetylase enzymes, which has prompted preclinical interest in cancer biology. There are essentially no human clinical trials of isolated allyl mercaptan as a supplement; it is more typically a metabolite of garlic intake rather than a stand-alone product.

Dosage

There is no established supplement dose for isolated allyl mercaptan. It is encountered as a natural metabolite from dietary garlic intake. DSLD label data is sparse.

When and how to take it

If consumed via garlic, time around meals is conventional. There is no evidence-based supplement timing.

1 commercial form

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Garlic-derived metabolite

Most exposure comes from eating garlic rather than from supplementation.

Formed endogenously from dietary garlic; volatile and rapidly exhaled.

Safety

Allyl mercaptan as a metabolite of dietary garlic has a long history of safe consumption. Concentrated isolated allyl mercaptan is a pungent, volatile thiol that can be irritating at high exposure. Industrial safety data sheets describe it as an inhalation and skin irritant.

Who should be cautious

Heavy garlic intake (rather than isolated allyl mercaptan) warrants caution before surgery and in those on blood thinners. Pregnancy and breastfeeding safety of isolated allyl mercaptan is unknown.

Interactions

Garlic intake (the practical source of allyl mercaptan) can mildly increase bleeding risk in combination with anticoagulants and antiplatelets. No specific interactions are documented for isolated allyl mercaptan supplementation.

Food sources

Garlic (fresh)

Amount
Variable; metabolite generated post-ingestion
%DV
—

Onion and other Alliums

Amount
Lower than garlic
%DV
—

Frequently asked questions

Why does garlic give you bad breath?⌄

Allyl mercaptan and related sulfur compounds from garlic are absorbed and then exhaled through the lungs over hours, producing the lingering odor.

Should I take allyl mercaptan as a supplement?⌄

There is no clinical evidence supporting isolated allyl mercaptan supplementation. Eating garlic remains a more practical and better-studied source.

References

Allyl Mercaptan on Wikidata — Wikidata link

Allyl Mercaptan (ChEBI:89888) — ChEBI link

Allyl Mercaptan (PubChem CID 13367) — PubChem link

Allyl Mercaptan on NIH DSLD (US supplement label database) — NIH Dietary Supplement Label Database link

Research on Allyl Mercaptan (PubMed search) — PubMed link

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Evidence-based·How we grade evidence

Disclaimer: These statements have not been evaluated by the FDA. This page is educational, not a substitute for personalized medical advice. Evidence grades are AI-assisted assessments — talk to your doctor before starting any new supplement, especially if you’re pregnant, breastfeeding, on medications, or managing a chronic condition.