Lysine is an essential amino acid crucial for collagen cross-linking — the enzymatic process that gives collagen its tensile strength. Lysine residues in collagen are hydroxylated and then cross-linked by lysyl oxidase to form the strong triple-helical network of healthy dermis. Also functions in carnitine production (energy metabolism) and supports hair strength. In skincare, lysine supports the collagen maturation process essential for firm, elastic skin.
Key Skin Benefits
+ Essential for collagen cross-linking — tensile strength
+ Substrate for lysyl oxidase — collagen maturation
+ Supports carnitine production — skin energy
+ Hair strengthening amino acid
+ Essential amino acid — must be obtained externally
Pros
+ + Crucial for collagen cross-linking
+ + Essential amino acid
+ + Supports skin firmness
+ + Hair and skin benefits
+ + Affordable
Cons
− − Not a direct anti-aging signal
− − Works as substrate, not stimulant
− − Limited cosmetic research
Specifications
Property
Value
Usage Areas
Face, Eye, Body, Hair
Product Type
Leave-On, Rinse-Off
Source
Synthetic / Fermentation
Natural Level
Natural-derived
Safety Ratings
Metric
Rating
Skin Sensitivity
1/5
Comedogenic Rating
0/5
EWG Score
1/10
Regional Regulatory Limits
Region
Leave-on %
Rinse-off %
Status
EU (CosIng)
No limit
No limit
Allowed
US (CIR/FDA)
No limit
No limit
Allowed
Japan (MHLW)
No limit
No limit
Allowed
ASEAN
No limit
No limit
Allowed
China (NMPA)
No limit
No limit
Allowed
Typical Usage % by Product Type
Product Type
Typical %
Serum
0.1 - 0.5%
Hair Treatment
0.5 - 2%
References
Siegel RC — Collagen cross-linking. Int Rev Connect Tissue Res (1979). PMID: 36964
Eyre DR et al. — Collagen cross-links. Annu Rev Biochem (1984). PMID: 6436904
Bailey AJ — Collagen maturation. Mech Ageing Dev (2001). PMID: 11389943