Methionine for Hair: What the Research Shows

Methionine is a sulfur-containing essential amino acid, and hair is one of the tissues that depends on it. In mice, a methionine-deficient diet caused hair loss, and hair growth resumed when methionine was restored. In people, the evidence is a 12-week trial of a multi-ingredient supplement that included methionine alongside drug treatments.

Here's what each study found and what it can't tell you.

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Key Takeaways

• Hair-follicle keratinocytes contain high levels of cysteine, which is derived from methionine.
• In mice fed a methionine-restricted diet, hair loss appeared within 14 days and hair growth resumed when methionine was restored.
• In an 83-person trial, a supplement with methionine, cysteine, taurine, collagen, iron and selenium, taken with drug treatment, improved hair loss ratings more than the drug treatment alone.
• We found no trial of methionine on its own for hair in people.

What Is Methionine?

Methionine is an amino acid you get from protein. Hair-follicle cells contain high levels of cysteine, which comes from methionine.

Does Methionine Help Hair?

Methionine is necessary for hair maintenance in mice. In people, it's one ingredient in supplements with other components, so it's not possible to say what methionine does alone.

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Getting Enough Methionine

• Protein. Eating enough protein is the usual route to methionine.
• Don't megadose. There's no evidence that more than you need helps hair.
• Ask your doctor before supplementing, especially if you're pregnant, breastfeeding, have a condition or take medication.

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What The Research Shows

A Mouse Study

Hair-follicle keratinocytes proliferate rapidly and contain high levels of cysteine, which comes from methionine. Mice fed a methionine-and-choline-deficient diet lost hair within 14 days, while mice that also received homocysteine did not. After two weeks of restriction, homocysteine could not rescue hair loss, but restoring dietary methionine did. The authors concluded hair maintenance requires dietary methionine (Kubota et al., 2024).

A Multi-Ingredient Trial

In a 12-week, randomized, assessor-blinded trial, 83 people with androgenetic alopecia or chronic telogen effluvium were given drug treatment alone or with a daily tablet containing hydrolyzed fish collagen, taurine, cysteine, methionine, iron and selenium. At week 12 the global assessment score was higher with the supplement (1.67 vs 0.66), and 50% vs 23% scored 2 or more. It was well tolerated (Milani et al., 2023). The tablet had many ingredients, and everyone also received drug treatment.

Methionine In Hair Keratin

In human hair, homocysteine-keratin increased along the hair fiber, 5 to 10 times higher at the tips than at the base, and methionine-keratin decreased. The authors proposed copper and iron-catalyzed demethylation of methionine as one route of keratin damage in hair (Borowczyk et al., 2018).

Taurine is another sulfur-containing amino acid; our article on taurine and hair covers what is known about it.

L-cysteine is the related sulfur-containing amino acid people ask about; see L-cysteine and hair.

For the blend trials that include it, see amino acids for hair growth.

Frequently Asked Questions

Does methionine help hair growth?

In mice, dietary methionine was needed to maintain hair. In people, a multi-ingredient supplement with methionine improved ratings alongside drug treatment, but methionine alone hasn't been tested.

What foods contain methionine?

It is found in dietary protein.

Is methionine safe?

Talk to your doctor before supplementing.

References

1. Kubota Y, Varshney N, Kobayashi K, et al. Methionine Dependence of Hair Maintenance in C57BL/6 Mice. In Vivo. 2024. PubMed
2. Milani M, Colombo F, GFM‐O‐Trial Investigators Group. Efficacy and tolerability of an oral supplement containing amino acids, iron, selenium, and marine hydrolyzed collagen in subjects with hair loss (androgenetic alopecia, AGA or FAGA or telogen effluvium). A prospective, randomized, 3-month, controlled, assessor-blinded study. Skin Res Technol. 2023. PubMed
3. Borowczyk K, Suliburska J, Jakubowski H. Demethylation of methionine and keratin damage in human hair. Amino Acids. 2018. PubMed