Ingredient review
R-Saccharomyces Polypeptide-1
INCI: R-SACCHAROMYCES POLYPEPTIDE-1
A gentle, yeast-derived peptide that helps hydrate and support the skin barrier, but research is still emerging.
In plain English
R-Saccharomyces Polypeptide-1 is a small protein fragment made by fermenting yeast. In skincare, it helps attract moisture to the skin and supports the skin's natural barrier, which keeps irritants out and water in. Think of it as a gentle helper that encourages your skin to stay plump and resilient.
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
- biotech
- Evidence
- emerging
- Irritation
- low
- Clogging risk
- low
Quick decision guide
Useful, but context matters
R-Saccharomyces 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.
- Step 1Start with the score, then check the irritation and clogging risk before judging R-Saccharomyces Polypeptide-1.
- 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 peptide produced through fermentation of Saccharomyces (a type of yeast). It is a short chain of amino acids that can signal skin cells to improve hydration and barrier function.
How it works
When applied topically, the polypeptide can bind to the skin's surface, helping to retain moisture and support the production of natural moisturizing factors. It may also encourage the skin to produce more ceramides and other lipids that strengthen the barrier.
Pros
Gentle on skin
Low irritation and comedogenic risk make it suitable for sensitive and acne-prone skin types.
Barrier-friendly
Helps maintain the skin's moisture barrier, which is essential for overall skin health and comfort.
Cons and cautions
Limited research
Most evidence comes from lab studies or small trials; large-scale human studies are still lacking.
Variable efficacy
Results depend heavily on the formulation and concentration, so not all products with this ingredient will perform equally.
Best for
- Anyone looking for a gentle, hydrating ingredient
- Those with dry or sensitive skin seeking barrier support
Use caution if
- Individuals with a known allergy to yeast or fermented ingredients
Usage tips
Safety summary
R-Saccharomyces Polypeptide-1 has a low irritation and comedogenic risk, making it safe for most skin types. However, those with yeast allergies should patch test first.
Research notes
Early research suggests benefits for hydration and barrier function, but more robust clinical studies are needed to confirm long-term efficacy.
Common label clues
- Typical concentration
- 0.1% to 2%
- Regulatory status
- Generally recognized as safe for cosmetic use in the US and EU, with no specific restrictions.
- Common uses
- Serums, Moisturizers, Eye creams, Anti-aging formulations
- Environmental note
- Produced via fermentation, which is generally considered a sustainable and low-impact manufacturing process.
Good to know
- This ingredient is often found in K-beauty and J-beauty products aimed at gentle hydration.
- It is not the same as live yeast; the fermentation process deactivates the yeast, leaving only the beneficial peptides.
Common questions
What is R-Saccharomyces Polypeptide-1 in beauty products?
R-Saccharomyces Polypeptide-1 is a small protein fragment made by fermenting yeast. In skincare, it helps attract moisture to the skin and supports the skin's natural barrier, which keeps irritants out and water in. Think of it as a gentle helper that encourages your skin to stay plump and resilient.
What does R-Saccharomyces Polypeptide-1 do in a beauty product?
When applied topically, the polypeptide can bind to the skin's surface, helping to retain moisture and support the production of natural moisturizing factors. It may also encourage the skin to produce more ceramides and other lipids that strengthen the barrier.
Is R-Saccharomyces Polypeptide-1 safe for most people?
R-Saccharomyces Polypeptide-1 has a low irritation and comedogenic risk, making it safe for most skin types. However, those with yeast allergies should patch test first.
Who should be careful with R-Saccharomyces Polypeptide-1?
Individuals with a known allergy to yeast or fermented ingredients
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.