Lysine
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What Is Lysine?
An essential amino acid that the body cannot produce. It supports collagen production and iron absorption, both of which are critical for healthy hair growth.
Source: Synthesized by fermentation or extracted from protein sources
Origin: Semi-synthetic
Also known as: L-Lysine, Lysine HCl
What Does Lysine Do to Your Hair?
Supports healthy hair growth by improving iron and zinc absorption, nutrients essential for hair follicle function. Contributes to collagen synthesis which supports the dermal papilla that nourishes hair follicles.
Best For
Thinning hair, iron-deficient hair loss, slow-growing hair, aging hair
Not Recommended For
None known
Concentration Matters
0.1-1% in hair products
Hair Type Compatibility
Method Compatibility
Safety & Regulation
Very safe for both topical and oral use. Commonly taken as a dietary supplement. No known adverse effects at standard cosmetic concentrations. Essential amino acid with well-established safety.
FDA Status: Generally Recognized As Safe
FDA considers safe for cosmetic and supplement use.
EWG Score: 1/10
HairAide Verdict
Most effective when taken orally as a supplement in combination with iron for hair loss related to iron deficiency. Topical application provides some benefit but oral supplementation has stronger clinical evidence.
Products That Contain Lysine
Hair growth supplements, scalp serums, strengthening treatments, amino acid complexes
Alternatives to Lysine
If you want to avoid Lysine, look for products with these ingredients instead:
Methionine, Arginine, Cysteine, Biotin
Frequently Asked Questions
Yes, Lysine has a safety rating of 9/10 and is generally considered safe for use in hair products. Very safe for both topical and oral use. Commonly taken as a dietary supplement. No known adverse effects at standard cosmetic concentrations. Essential amino acid with well-established safety.
Lysine is CG-method approved and is generally considered safe for curly hair.
Yes, Lysine is approved for the Curly Girl method.
Some alternatives to Lysine include: Methionine, Arginine, Cysteine, Biotin
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