HISTORY
Papaya (Carica papaya) has long been valued in traditional beauty and wellness practices across tropical regions for its skin-smoothing properties. The fruit naturally contains papain, a protease enzyme that breaks down surface proteins, which led many cultures to use mashed papaya pulp as a gentle way to soften and refresh the skin. Papaya later spread across Asia through maritime trade and eventually reached Japan, where it adapted well to the warm climates of Okinawa and southern Kyushu. In Okinawa, green papaya became part of the local diet and traditional health practices, valued for supporting digestion and vitality. Over time, Japanese cosmetic researchers became interested in papain’s protein-dissolving ability, particularly during the rise of enzyme cleansers in the late 20th century. This interest aligned with Japan’s beauty philosophy of maintaining smooth, clear bihada (美肌) skin through gentle daily care. Modern skincare continues this evolution by isolating papain as a precise enzymatic exfoliant, allowing formulators to deliver consistent resurfacing benefits while maintaining skin comfort.
SCIENCE
Papain is a natural enzyme found in papaya, and in skincare, it helps remove dead skin cells from the surface. Unlike scrubs that use rough particles, papain breaks down the proteins that make dead skin stick. That’s why it’s called an enzyme exfoliant. It leaves skin feeling smoother and looking brighter, but is gentler than many physical scrubs. Recent research supports papain as a valuable ingredient in exfoliating and skin-renewing products.
Papain is popular because it works well in gentle skincare products. How well it works depends on the formula’s pH, the amount of papain, and how long it’s left on the skin. Recent studies show papain is most effective around pH 6 to 7, which is close to the skin’s natural level and milder than many strong acids. Older research also found that papain stays active between pH 5 and 7. This is why papain is often used in enzyme cleansers, wash-off masks, and exfoliating powders for regular use.
Studies also show that papain can be effective even at relatively small amounts. In laboratory testing, papain was able to break down proteins such as collagen and keratin, which helps explain its exfoliating effect on dull, rough skin. One study found that papain worked better at higher tested concentrations, and that its activity could be improved further when combined with certain helper ingredients that made it easier for the enzyme to act on tougher proteins. Another study found that when papain was built into a special membrane material, the enzyme activity was about 3 times higher than in a more conventional papain cosmetic at the same concentration. This shows that the way papain is delivered in a formula can make a big difference to how well it performs.
Papain should be used with care. Since it breaks down proteins, using too much or leaving it on too long can weaken the skin barrier instead of just removing dead cells. Studies on human skin cells found that papain could harm important barrier proteins, and animal tests showed it could increase water loss from the skin, which means the barrier is damaged. A weak barrier can make skin dry, sensitive, or more reactive. So, the best products use papain in the right amount and in formulas that stay gentle on the skin.
In summary, papain is a gentle but effective exfoliating enzyme. It loosens dead skin cells, smooths rough areas, and brightens the skin without the harshness of a scrub. Like other active ingredients, its benefits depend on good formulation and correct use. When used properly, papain can give skin a fresh, soft, and polished look that many people want from enzyme cleansers and masks.
REFERENCES
- Venetikidou, M., Lykartsi, E., Adamantidi, T., Prokopiou, V., Ofrydopoulou, A., Letsiou, S., & Tsoupras, A. (2025). Proteolytic enzyme activities of bromelain, ficin, and papain from fruit by-products and potential applications in sustainable and functional cosmetics for skincare. Applied Sciences, 15(5), 2637.
- Trevisol, T. C. (2023). Papain as cosmetic exfoliant: in vitro effect in proteins of the skin and immobilization in beauty face masks of starch and carboxymethyl cellulose.
- Banchhor, M., & Saraf, S. (2008). Potentiality of papain as an antiaging agent in cosmetic formulation.Pharmacognosy Reviews,2(4), 266.
- Li, Z., Liu, Y., Zhang, Z., & Wu, H. (2022). Preparation of a papain-embedding biological membrane material and its application in the skin-whitening products.China Surfactant Detergent & Cosmetics (1001-1803),52(3).
- Stremnitzer, C., Manzano-Szalai, K., Willensdorfer, A., Starkl, P., Pieper, M., König, P., ... & Jensen-Jarolim, E. (2015). Papain degrades tight junction proteins of human keratinocytes in vitro and sensitizes C57BL/6 mice via the skin independent of its enzymatic activity or TLR4 activation.Journal of Investigative Dermatology,135(7), 1790-1800.
