Methionine
Essential sulphur-containing amino acid. In cosmetics appears in amino acid complexes and in formulas claiming to strengthen the hair follicle: methionine is a sulphur source for keratin synthesis. On skin works as an NMF component with antioxidant potential due to its sulphur group.
Evidence by route
Topical application
Safe amino acid component. Hair-strengthening claims are better supported systemically than topically.
- CIR Cosmetic Ingredient Review safety assessment.
How to read tiers A–F
- CWeak evidence. In vitro data, open-label studies, or expert consensus
Tolerability and safety
- Irritation potential
- Low
- Allergen risk
- Low
- Pregnancy
- Safe
- Suitable for
- Normal, Dry, Combination, Oily, Sensitive
About this ingredient
Methionine (L-Methionine) is an essential sulfur-containing alpha-amino acid. In skin it serves as a methyl donor in methylation reactions and a precursor of cysteine and glutathione – key antioxidant molecules. Mechanism. Supports glutathione synthesis – the main keratinocyte antioxidant. The sulfur group protects proteins from oxidative stress. Humectant: binds water in the stratum corneum. Where applied. Serums and creams for mature skin and pigmentation, damaged-hair products (methionine is a structural component of keratin). Concentration 0.1–2%. Often in amino-acid complexes with lysine, arginine, cysteine. Evidence base. No clinical RCTs of topical methionine. Main base – oral use in liver and hair disorders. CIR confirmed safety. Pregnancy and lactation – topically safe. Hypoallergenic, non-comedogenic.
Frequently asked questions
Is Methionine safe during pregnancy?
Methionine is considered safe during pregnancy at typical cosmetic concentrations. Systemic absorption through the skin is minimal.
What skin types is Methionine for?
Methionine suits: normal, dry, combination, oily, sensitive.
What is Methionine and what does it do in cosmetics?
Essential sulphur-containing amino acid.
What's the INCI name for Methionine?
The INCI name is Methionine. It may also appear as: L-Methionine.
See Methionine in a product composition right on the store page
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