What Is Pepsin?
Pepsin is an enzyme traditionally extracted from the lining of porcine stomachs, although some modern suppliers produce it through fermentation using genetically engineered microorganisms for a more sustainable and ethically flexible option. Chemically it belongs to the family of proteases, meaning it breaks down proteins into smaller fragments called peptides and amino acids. Discovered in the early 1800s, pepsin was first valued for its role in food digestion studies, then slowly made its way into topical formulas when chemists noticed its gentle protein-dissolving action on skin and hair surfaces. Commercial production starts with purifying the raw enzyme, concentrating it, then stabilizing it with safe preservatives so it holds up in creams, lotions or gels. You will most often see pepsin in exfoliating masks, clarifying shampoos, revitalizing scalp serums, anti-aging leave-ons, specialty hand creams and targeted foot treatments where a controlled softening effect is desired.
Pepsin’s Cosmetic Benefits/Uses
In personal care formulas pepsin is prized for two main roles
- Hair conditioning: By nibbling away at damaged protein bonds on the hair surface it helps smooth rough cuticles, leading to strands that look shinier, feel softer and are easier to detangle
- Skin conditioning: Its gentle proteolytic action loosens dead skin cells so fresher cells can surface, which leaves the complexion smoother and better able to absorb moisturizing ingredients
Who Can Use Pepsin
Pepsin-containing products are generally suitable for normal, oily and combination skin as well as most hair types because the enzyme’s mild protein-softening action is not overly harsh. Those with very sensitive or compromised skin should proceed with caution since any protease can potentially disrupt an already weakened barrier, leading to redness or stinging. Dry or eczema-prone users may prefer a formula where pepsin is paired with rich emollients to offset possible tightness.
Because traditional pepsin is sourced from porcine stomachs it is not considered vegan or vegetarian friendly. Some brands now offer fermentation-derived pepsin that sidesteps animal harvesting, but labeling is not yet standardized, so shoppers who avoid animal ingredients should verify the enzyme’s origin with the manufacturer.
Current research does not flag topical pepsin as harmful during pregnancy or breastfeeding, yet hormone-driven skin shifts can heighten sensitivity. This is not medical advice and expectant or nursing mothers should ask their healthcare provider before adding any new skincare or haircare product.
The ingredient is not known to cause photosensitivity, so daylight exposure is not a major concern. Still, daily sunscreen remains the gold standard for overall skin health. People with a history of protein or meat allergies should be mindful, as pepsin may theoretically trigger a reaction, although reports are rare.
Potential Side Effects/Adverse Reactions
Responses to topical pepsin vary from person to person. The points below outline potential effects that could occur, though most users will not experience them when the ingredient is formulated and used correctly.
- Irritation: Mild burning, stinging or redness can appear if the enzyme concentration is too high or the skin barrier is already compromised
- Dryness or tightness: Over-exfoliation may strip surface proteins faster than the skin can replenish them
- Scalp sensitivity: Itchiness or flaking could develop when leave-on hair products containing pepsin are left on the scalp for prolonged periods
If any discomfort, prolonged redness or swelling occurs stop using the product and seek advice from a qualified healthcare professional.
Comedogenic Rating
Rating: 0 (non-comedogenic)
Pepsin is a large, water-soluble enzyme that does not contain oils or waxy residues capable of blocking pores, so it carries virtually no risk of forming comedones. Its job is to break down proteins on the skin’s surface, not to sit in follicles or harden inside them. For this reason it is generally considered safe for people who are prone to acne or frequent breakouts.
Because pepsin works best in water-based formulations, it is usually paired with lightweight vehicles that further minimize any pore-clogging potential.
Summary
Pepsin serves two key roles in cosmetics: it conditions skin by digesting the protein “glue” that holds dead cells together so newer, smoother cells can surface, and it conditions hair by gently pruning damaged protein bonds which helps smooth cuticles for softer, shinier strands. Although effective, it remains a niche ingredient mostly found in specialty exfoliating masks, scalp serums and a handful of clarifying shampoos rather than in everyday cleansers or moisturizers.
Overall safety is good when formulas use appropriate concentrations, with irritation or dryness appearing only if skin is already sensitive or the product is left on too long. As with any new skincare or haircare addition, performing a quick patch test is a smart precaution before applying pepsin-containing products more broadly.