Ingredient review
SH-Polypeptide-18
INCI: SH-Polypeptide-18
SH-Polypeptide-18 is a synthetic peptide that mimics the action of botulinum toxin to soften expression lines, offering a non-invasive alternative for wrinkle reduction.
In plain English
SH-Polypeptide-18 is a lab-made protein fragment that works like a gentle muscle relaxant for your skin. When applied in a cream or serum, it can help soften the look of frown lines and crow's feet by temporarily calming the tiny muscles under the skin. It's not a permanent fix, but with regular use it may make fine lines less noticeable.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Risk flags are low for most users, though the finished product can still irritate.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
SH-Polypeptide-18 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.
- Step 1Start with the score, then check the irritation and clogging risk before judging SH-Polypeptide-18.
- Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
- 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
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
SH-Polypeptide-18 is a synthetic peptide, specifically a fragment of a protein that mimics the action of SNAP-25, a protein involved in muscle contraction. It is designed to be applied topically in skincare products.
How it works
It works by interfering with the release of neurotransmitters at the neuromuscular junction, similar to how botulinum toxin works but much milder. This reduces the intensity of muscle contractions under the skin, which in turn softens the appearance of dynamic wrinkles like crow's feet and forehead lines.
Pros
Gentle wrinkle softening
It offers a mild, non-invasive way to reduce the look of expression lines without needles or downtime.
Easy to incorporate
Works well in serums and creams, and can be used alongside most other skincare ingredients.
Cons and cautions
Temporary results
Effects fade within weeks of stopping use, so you need to keep applying the product regularly to maintain benefits.
Limited for deep wrinkles
It's best for fine lines and moderate wrinkles; deeper folds may not respond as well.
Best for
- Adults looking to soften early signs of aging
- People who prefer topical treatments over injectables
Use caution if
- Pregnant or nursing individuals (due to lack of safety data)
- Those with very sensitive skin or allergies to peptides
Usage tips
Safety summary
SH-Polypeptide-18 is considered safe for topical use in cosmetics at typical concentrations. Mild irritation is rare, but patch testing is recommended for sensitive skin. There is insufficient data on use during pregnancy or nursing.
Research notes
Clinical studies show modest improvement in wrinkle depth and skin smoothness over 8-12 weeks. Most evidence comes from small trials or ingredient manufacturer data. More independent research is needed.
Common label clues
- Typical concentration
- 0.001% to 0.1%
- Regulatory status
- Approved as a cosmetic ingredient in the EU, US, and many other regions. Not classified as a drug.
- Common uses
- Anti-aging serums, Eye creams, Facial moisturizers
- Environmental note
- Synthetic production means no animal or plant harvesting, but manufacturing involves chemical synthesis with typical environmental considerations.
Good to know
- Often combined with other peptides or antioxidants for enhanced anti-aging effects
- Not a substitute for sunscreen—always use SPF daily
Common questions
What is SH-Polypeptide-18 in beauty products?
SH-Polypeptide-18 is a lab-made protein fragment that works like a gentle muscle relaxant for your skin. When applied in a cream or serum, it can help soften the look of frown lines and crow's feet by temporarily calming the tiny muscles under the skin. It's not a permanent fix, but with regular use it may make fine lines less noticeable.
What does SH-Polypeptide-18 do in a beauty product?
It works by interfering with the release of neurotransmitters at the neuromuscular junction, similar to how botulinum toxin works but much milder. This reduces the intensity of muscle contractions under the skin, which in turn softens the appearance of dynamic wrinkles like crow's feet and forehead lines.
Is SH-Polypeptide-18 safe for most people?
SH-Polypeptide-18 is considered safe for topical use in cosmetics at typical concentrations. Mild irritation is rare, but patch testing is recommended for sensitive skin. There is insufficient data on use during pregnancy or nursing.
Who should be careful with SH-Polypeptide-18?
Pregnant or nursing individuals (due to lack of safety data) Those with very sensitive skin or allergies to peptides
Research sources
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.