Ingredient review
SH-Tetrapeptide-39
INCI: SH-Tetrapeptide-39
A lab-made peptide that may help firm skin and soften fine lines, but human studies are still limited.
In plain English
SH-Tetrapeptide-39 is a short chain of amino acids (the building blocks of protein) made in a lab. When applied to skin in a cream or serum, it's thought to send signals that encourage collagen production and help skin look firmer and smoother. Because it's a newer ingredient, most of the evidence comes from lab tests rather than large human studies.
Review score
Safety, usefulness, and evidence
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
- synthetic
- Evidence
- emerging
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
SH-Tetrapeptide-39 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-Tetrapeptide-39.
- 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
emergingThe ingredient may be promising, but claims should be treated more cautiously.
What it is
A synthetic tetrapeptide (four amino acids linked together) engineered to mimic natural signaling molecules in the skin. It is often included in anti-aging products at very low concentrations.
How it works
Peptides like SH-Tetrapeptide-39 are believed to penetrate the outer layer of skin and act as messengers, telling skin cells to produce more collagen and elastin. This can help improve skin firmness and reduce the appearance of fine lines over time.
Pros
Gentle on skin
SH-Tetrapeptide-39 has a low irritation risk, making it suitable for sensitive skin types that cannot tolerate stronger actives like retinol.
Targeted anti-aging support
It is specifically designed to encourage collagen production, which can help improve skin firmness and reduce fine lines over time.
Cons and cautions
Limited human research
Most evidence for this specific peptide comes from lab studies or small trials, so its real-world effectiveness is not as well-established as some other anti-aging ingredients.
Slow, subtle results
Peptides work gradually, and noticeable improvements may take weeks to months of consistent use. Users expecting quick changes may be disappointed.
Best for
- Adults looking for anti-aging support
- Those with sensitive skin who want a gentle active ingredient
Use caution if
- Anyone allergic to any component of the peptide blend
- Those seeking immediate or dramatic results (peptides work gradually)
Usage tips
Safety summary
SH-Tetrapeptide-39 is considered safe for topical cosmetic use at typical concentrations. It has low irritation and comedogenic potential. As with any new ingredient, patch test before widespread use.
Research notes
Research on SH-Tetrapeptide-39 is still emerging. Preliminary in vitro studies suggest it may stimulate collagen synthesis, but large-scale human clinical trials are lacking. Most evidence is extrapolated from studies of similar peptides.
Common label clues
- Typical concentration
- 0.001% to 0.1%
- Regulatory status
- Approved as a cosmetic ingredient in the EU, US, and other major markets. Not regulated as a drug.
- Common uses
- Anti-aging serums, Eye creams, Facial moisturizers
- Environmental note
- Synthetic peptides are produced in controlled lab settings, which reduces environmental impact compared to harvesting from natural sources.
Good to know
- SH-Tetrapeptide-39 is often combined with other peptides or antioxidants in anti-aging formulas.
- It is stable in most formulations but can be degraded by very low pH (under 4.0).
Common questions
What is SH-Tetrapeptide-39 in beauty products?
SH-Tetrapeptide-39 is a short chain of amino acids (the building blocks of protein) made in a lab. When applied to skin in a cream or serum, it's thought to send signals that encourage collagen production and help skin look firmer and smoother. Because it's a newer ingredient, most of the evidence comes from lab tests rather than large human studies.
What does SH-Tetrapeptide-39 do in a beauty product?
Peptides like SH-Tetrapeptide-39 are believed to penetrate the outer layer of skin and act as messengers, telling skin cells to produce more collagen and elastin. This can help improve skin firmness and reduce the appearance of fine lines over time.
Is SH-Tetrapeptide-39 safe for most people?
SH-Tetrapeptide-39 is considered safe for topical cosmetic use at typical concentrations. It has low irritation and comedogenic potential. As with any new ingredient, patch test before widespread use.
Who should be careful with SH-Tetrapeptide-39?
Anyone allergic to any component of the peptide blend Those seeking immediate or dramatic results (peptides work gradually)
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.