Hydrolyzed Silk
Silk protein broken into small fragments. It adds a smooth, silky feel and shine and helps hair hold moisture.
About Hydrolyzed Silk
Hydrolyzed silk comes from the protein fibers of silkworm cocoons — mainly fibroin — broken down into small peptides that dissolve in water. It is a popular protein in leave-ins, conditioners and styling products for textured hair because it gives a noticeably smooth, silky finish without much stiffness.
Like other hydrolyzed proteins, it works mostly on the surface of the hair. It forms a thin film that smooths the cuticle, adds shine and helps hair hold on to water, and the smallest fragments can settle into damaged areas. Compared with keratin, many people find silk gentler and lighter; it is often used when hair needs a little reinforcement without a 'protein treatment' feel.
Who tends to love it: people with fine curls that need softness and definition, people with relaxed or colored hair, and high porosity hair that loses moisture fast. Who should watch it: protein-sensitive hair, which can still become stiff or crunchy if silk is used in every product, and some people with low porosity hair. If your hair starts to feel rough or snaps easily when dry, take a break from protein and focus on moisture for a couple of weeks.
Hydrolyzed silk is approved for the Curly Girl Method. The related ingredient 'silk amino acids' is even smaller and acts more like a humectant.
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.
Also listed as
- silk protein
- hydrolyzed silk protein
- hydrolysed silk
- liquid silk
Similar ingredients
Sources
Last data update:
- Robbins CR. Chemical and Physical Behavior of Human Hair. 5th ed. Springer; 2012. Reference text on hair structure, surfactants, conditioning agents, protein, heat and chemical treatments.
- Cosmetic Ingredient Review (CIR). Ingredient safety assessments. Safety assessments for cosmetic ingredients cited on ingredient pages.
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