Ingredient review

Silkworm Polypeptide-1

INCI: SR-SILKWORM POLYPEPTIDE-1

A gentle, hydrating peptide from silkworm silk that may help support skin moisture and texture, but research is still emerging.

beautyskincarehumectant

In plain English

This ingredient is a small protein fragment (a peptide) derived from silkworm silk. In skincare, it acts like a sponge to attract and hold water on the skin's surface, helping to keep it hydrated and smooth. Think of it as a lightweight, natural moisturizer that also helps condition the skin.

Review score

Safety, usefulness, and evidence

3.8Good
3.8/ 5

Potentially useful with some tradeoffs

The evidence base is still emerging, so marketing claims deserve extra caution.

Risk flags are low for most users, though the finished product can still irritate.

Source
natural
Evidence
emerging
Irritation
low
Clogging risk
low
How reviews are scored

Quick decision guide

Useful, but context matters

Silkworm Polypeptide-1 is generally a lower-concern ingredient when the full formula suits your skin.

Plain-English read

Treat this as a practical screening step before you compare products that contain this ingredient.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Silkworm Polypeptide-1.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.

Score terms in plain English

Irritation risk

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

emerging

The ingredient may be promising, but claims should be treated more cautiously.

What it is

A polypeptide (chain of amino acids) extracted from the silk produced by silkworms (Bombyx mori). It is processed to be small enough to be used in cosmetic formulas.

How it works

It forms a thin, breathable film on the skin that helps reduce water loss (transepidermal water loss, or TEWL) while attracting moisture from the air. This film also gives a temporary smoothing effect, making the skin feel softer.

Pros

Lightweight hydration

Attracts moisture to the skin without feeling heavy or sticky, making it suitable for layering under other products.

Gentle on skin

Has a low irritation and comedogenic risk, so it's generally safe for sensitive and acne-prone skin types.

Cons and cautions

Limited research

Most evidence comes from lab studies or small trials; large-scale human studies on anti-aging or firming benefits are lacking.

Variable efficacy

Its performance depends heavily on the formula and concentration; not all products deliver enough peptide to make a noticeable difference.

Best for

  • People with dry or dehydrated skin
  • Those looking for a gentle, natural humectant

Use caution if

  • Individuals with known silk protein allergy (rare)

Usage tips

Apply after cleansing and before heavier creams to maximize absorption.
Pair with a moisturizer containing occlusive ingredients (like shea butter or squalane) to lock in the hydration.

Safety summary

Considered safe for topical use with very low irritation and allergy potential. Rare allergic reactions may occur in individuals with silk protein sensitivity.

Research notes

Preliminary in vitro and small human studies suggest humectant and film-forming properties. More robust clinical trials are needed to confirm anti-aging or firming claims.

Common label clues

Typical concentration
0.1% to 2%
Regulatory status
Generally recognized as safe for cosmetic use in the US and EU when used as directed. Not a drug ingredient.
Common uses
Serums, Moisturizers, Anti-aging creams
Environmental note
Silkworm farming for cosmetics is typically a byproduct of the silk textile industry, but ethical sourcing varies. Look for brands that disclose sustainable practices.

Good to know

  • Silkworm polypeptides are often used in luxury or 'silk protein' skincare lines.
  • This ingredient is not the same as synthetic peptides designed to mimic collagen signaling.

Common questions

What is Silkworm Polypeptide-1 in beauty products?

This ingredient is a small protein fragment (a peptide) derived from silkworm silk. In skincare, it acts like a sponge to attract and hold water on the skin's surface, helping to keep it hydrated and smooth. Think of it as a lightweight, natural moisturizer that also helps condition the skin.

What does Silkworm Polypeptide-1 do in a beauty product?

It forms a thin, breathable film on the skin that helps reduce water loss (transepidermal water loss, or TEWL) while attracting moisture from the air. This film also gives a temporary smoothing effect, making the skin feel softer.

Is Silkworm Polypeptide-1 safe for most people?

Considered safe for topical use with very low irritation and allergy potential. Rare allergic reactions may occur in individuals with silk protein sensitivity.

Who should be careful with Silkworm Polypeptide-1?

Individuals with known silk protein allergy (rare)

Research sources

Cosmetic Ingredient Review (CIR) - Safety of Silk ProteinsOpenPubMed - Silk peptides in skincareOpenINCI Database - SR-SILKWORM POLYPEPTIDE-1Open

Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.