What it does
- Hydrates and conditions skin and hair.
- Acts as a gentle, amino-acid pH adjuster (often paired with acids).
- Supports softness, strength-feel and manageability in hair.
How it works
Arginine is a basic amino acid widely documented as a humectant and conditioning agent; because it is mildly alkaline, it is often used to neutralise acids (such as carbomer or AHA blends) for a gentler, amino-acid-based pH adjustment. In hair care it supports smoothness and manageability.
Use level
- Typical use level
- typically 0.2–5% (less for pH adjustment)
Commonly used at 0.2–5% for conditioning/hydration, and at lower levels purely to adjust pH.
Formulation considerations
- Water-soluble; add to the water phase.
- Mildly alkaline — useful for neutralising acidic gellants and actives.
- Gentle and broadly compatible.
What it pairs with & what to avoid
Pairs well with
- Acidic gellants/actives (as a neutraliser)
- Other amino acids and humectants
Use with care / avoid
- No notable incompatibilities at typical levels
Regulatory status
Arginine is listed in the EU CosIng database and is a well-established cosmetic ingredient.
Common questions
What does arginine do in skincare?
It hydrates and conditions, and works as a gentle amino-acid pH adjuster.
Is arginine good for hair?
Yes; it supports softness, a stronger feel and manageability in hair products.
What percentage of arginine is used?
Commonly 0.2–5% for conditioning; less for pH adjustment.