Rh-Polypeptide-25: What Is It, Cosmetic Uses, Benefits & Side Effects

Curious about this ingredient? In this article we're explaining exactly what it is and why it's used within cosmetic formulations.
Updated on: June 30, 2025
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We verify all information on this page using publicly available nomenclature standards from The Personal Care Products Council (PCPC), the European Commission's CosIng database and documentation provided directly by ingredient manufacturers. Our analysis is based on technical data from these sources to ensure accuracy and reliability.

What Is Rh-Polypeptide-25?

Rh-Polypeptide-25 is a lab made version of a tiny protein, or peptide, that mirrors part of the naturally occurring human molecule Interleukin-2. Scientists start with the exact gene from a human cell, insert it into a harmless strain of E. coli, then let the bacteria ferment in large tanks. The bacteria act like factories, producing the peptide in high amounts. After fermentation the peptide is carefully purified, checked for quality and blended into a stable cosmetic grade powder or solution.

Chemically, Rh-Polypeptide-25 is a single chain of up to 153 amino acids, built only from the 20 standard amino acids found in skin. It can form small disulfide bridges and may carry simple sugar decorations, both of which help the peptide fold into a shape that skin cells can recognize.

Interest in bioengineered peptides took off in the early 2000s when brands began looking for gentle but high-performance alternatives to traditional actives like retinol and acids. Rh-Polypeptide-25 entered cosmetic labs soon after, thanks to advances in fermentation technology that made production efficient and reproducible.

Today you can spot Rh-Polypeptide-25 in lightweight serums, anti aging creams, daily moisturizers, sheet masks, targeted eye treatments and after-sun soothing formulas where brands want to signal premium science backed skin care without using strong drugs or hormones.

Rh-Polypeptide-25’s Cosmetic Benefits/Uses

In cosmetic products Rh-Polypeptide-25 is valued for one primary role:

Skin conditioning – The peptide supports the skin’s own renewal signals, helping cells hold on to moisture and maintain a smooth surface. With regular use formulas containing Rh-Polypeptide-25 can leave skin feeling softer, more supple and visibly refreshed which is why it is often featured in anti aging and recovery focused products.

Who Can Use Rh-Polypeptide-25

Rh-Polypeptide-25 is considered gentle enough for most skin types including dry, normal, combination, oily and even sensitive complexions because it mimics molecules the body already knows. People with extremely reactive or allergy-prone skin should still check the full ingredient list of any formula since irritation is usually caused by other additives rather than the peptide itself.

The peptide is produced through fermentation in E. coli with no animal-derived raw materials so it is generally viewed as suitable for both vegans and vegetarians.

No specific warnings exist for topical use during pregnancy or breastfeeding, yet clinical data in these groups is very limited. This information is not medical advice; anyone who is pregnant or nursing should show the product to a qualified healthcare professional before adding it to a routine.

Rh-Polypeptide-25 does not make skin more sensitive to sunlight, so it does not increase the need for extra sun protection beyond the daily SPF that dermatologists already recommend.

The ingredient pairs well with most common actives such as niacinamide, hyaluronic acid, gentle exfoliating acids and retinoids without known incompatibilities.

Potential Side Effects/Adverse Reactions

Side effects from topical Rh-Polypeptide-25 vary from person to person. The points below describe possible reactions even though most users experience none when the ingredient is formulated and stored correctly.

  • Mild redness or warmth shortly after application
  • Temporary itching or stinging on very sensitive skin
  • Localized rash or hives in those with a specific peptide allergy
  • Contact dermatitis if the formula contains additional sensitizing ingredients
  • Eye irritation if the product migrates into the eyes

If you notice any of the reactions above stop using the product immediately and seek advice from a healthcare professional.

Comedogenic Rating

Rh-Polypeptide-25 has a comedogenic rating of 0. It is a water based peptide with no inherent oils or waxes so it does not sit in pores or block sebum flow. Typical use levels are low and the molecule rinses cleanly from skin, keeping the risk of congestion minimal.

Because of this Rh-Polypeptide-25 is generally considered a safe choice for acne prone or breakout prone skin.

Only remember that the overall pore friendliness of a finished product depends on the complete formula. Heavy butters or rich silicones added for texture can negate the peptide’s non-comedogenic nature.

Summary

Rh-Polypeptide-25 is a lab crafted fragment of Interleukin-2 that works as a skin conditioning agent. By mimicking natural repair signals it helps cells hold water, smooth rough patches and bounce back from daily stress.

While not yet a household name it is popping up more often in high end serums masks and eye creams as brands look for gentle science backed actives.

Topical use appears very safe with only isolated reports of mild irritation. As with any new skincare ingredient do a quick patch test before full face use to make sure your skin agrees with it.

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