Ingredient review
Pepsin
INCI: PEPSIN
Pepsin is an enzyme exfoliant that breaks down proteins on the skin, but its use in cosmetics is rare and not well-studied for safety or efficacy.
In plain English
Pepsin is an enzyme that normally helps digest proteins in your stomach. In skincare, it's sometimes added to exfoliating products to gently break down dead skin cells, which are made of protein. However, it's not a common or well-researched ingredient for cosmetic use, and its effectiveness on skin is uncertain.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is still emerging, so marketing claims deserve extra caution.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- natural
- Evidence
- emerging
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Pepsin can be useful, but watch for some irritation potential.
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 Pepsin.
- 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
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
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
Pepsin is a proteolytic enzyme (a protein-digesting enzyme) naturally produced in the stomach to break down dietary proteins. In cosmetics, it is used as an exfoliant to dissolve dead skin cells.
How it works
Pepsin works by breaking peptide bonds in proteins, including keratin in the outer layer of skin. When applied topically, it can help loosen and remove dead skin cells, potentially smoothing skin texture. However, its activity depends on pH (it works best in acidic conditions) and may be less predictable on skin than in the stomach.
Pros
Gentle exfoliation
Pepsin can break down dead skin proteins without the harshness of physical scrubs, making it a milder option for exfoliation.
Novel ingredient
For those interested in unique or enzyme-based skincare, pepsin offers a different mechanism compared to common AHAs or BHAs.
Cons and cautions
Limited evidence
There is very little scientific research on pepsin's safety or effectiveness in cosmetic products, so its benefits are not well-established.
Potential irritation
As a protein-digesting enzyme, pepsin may irritate the skin if left on too long or used at too high a concentration, especially on sensitive skin.
Best for
- People looking for a gentle enzymatic exfoliant alternative to acids.
- Those with normal to oily skin who tolerate enzyme exfoliants well.
Use caution if
- Individuals with sensitive, irritated, or compromised skin barriers.
- Anyone with known allergies to pepsin or animal-derived enzymes.
Usage tips
Safety summary
Pepsin appears to have low acute toxicity, but its use in cosmetics is not well-studied. Potential for skin irritation exists, especially in leave-on products or at high concentrations. Limited data on long-term safety.
Research notes
There is minimal peer-reviewed research on pepsin in cosmetic applications. Most knowledge comes from its use in digestive health and food processing. Its efficacy as a topical exfoliant is anecdotal rather than evidence-based.
Common label clues
- Typical concentration
- Typically used at very low concentrations (0.1–1%) in rinse-off formulations.
- Regulatory status
- Pepsin is not specifically regulated as a cosmetic ingredient in most regions, but it is generally considered safe for use in rinse-off products at low concentrations. No known restrictions.
- Common uses
- Exfoliating treatments, Peeling products
- Environmental note
- Pepsin is typically sourced from animal by-products, which may raise sustainability or ethical concerns for some consumers.
Good to know
- Pepsin is typically derived from animal sources (e.g., pig stomach), so it may not be suitable for vegans.
- Its activity is highly pH-dependent; it works best in acidic environments (pH 1.5–3.5), which is much lower than skin's natural pH.
Common questions
What is Pepsin in beauty products?
Pepsin is an enzyme that normally helps digest proteins in your stomach. In skincare, it's sometimes added to exfoliating products to gently break down dead skin cells, which are made of protein. However, it's not a common or well-researched ingredient for cosmetic use, and its effectiveness on skin is uncertain.
What does Pepsin do in a beauty product?
Pepsin works by breaking peptide bonds in proteins, including keratin in the outer layer of skin. When applied topically, it can help loosen and remove dead skin cells, potentially smoothing skin texture. However, its activity depends on pH (it works best in acidic conditions) and may be less predictable on skin than in the stomach.
Is Pepsin safe for most people?
Pepsin appears to have low acute toxicity, but its use in cosmetics is not well-studied. Potential for skin irritation exists, especially in leave-on products or at high concentrations. Limited data on long-term safety.
Who should be careful with Pepsin?
Individuals with sensitive, irritated, or compromised skin barriers. Anyone with known allergies to pepsin or animal-derived enzymes.
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.