Keratin Amino Acids
Protein CG-friendly
The individual amino acids that make up keratin. Very small, so they help hair hold moisture and can reach slightly into damaged areas.
How our checker rates it
| Mode | Rating | Why |
|---|---|---|
| Curly Girl | OK | No concerns for this mode. |
| Relaxed hair | Good | Protein — helps reinforce chemically weakened hair. Balance it with moisture. |
| Low porosity | Caution | Protein high in the list can leave low-porosity hair stiff. Use protein sparingly. |
| Protein-sensitive | Avoid | Protein — #1 on the list. |
Ratings assume it is listed near the top of the label. After the first preservative or fragrance (likely 1% or less) most cautions soften.
What protein ingredients do
Hydrolyzed proteins, peptides and amino acids that temporarily patch gaps in the cuticle and add strength. Some hair turns stiff or brittle with too much.
Similar ingredients
Sources
Last data update:
- Cosmetic Ingredient Review (CIR). Ingredient safety assessments. Safety assessments for cosmetic ingredients cited on ingredient pages.
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