Rh-Polypeptide-66: 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-66?

Rh-Polypeptide-66 is a lab engineered version of a human protein called SIRT1, part of the sirtuin family of enzymes involved in cellular repair and longevity. The “Rh” prefix signals that the peptide is produced using recombinant technology, meaning scientists insert the genetic code for SIRT1 into harmless host cells like yeast or bacteria that then churn out large amounts of the protein. After fermentation the mixture is purified, filtered and carefully dried to yield a stable powder suited for cosmetic use.

Interest in SIRT1 began in the early 2000s when researchers linked it to healthy aging in skin cells. Formulators soon explored ways to deliver the enzyme topically, leading to Rh-Polypeptide-66. Because the peptide is created in controlled lab settings it avoids animal-derived contaminants and can be standardized for consistent quality.

You will most often spot Rh-Polypeptide-66 in anti-aging serums, rich moisturizers, sheet masks, eye creams and targeted “age-repair” ampoules. It is usually paired with hydrating agents and antioxidants to round out a rejuvenating blend.

Rh-Polypeptide-66’s Cosmetic Benefits/Uses

Rh-Polypeptide-66 is prized for one primary role in skin care.

As a skin conditioning agent it helps improve the overall feel and appearance of the complexion. By supporting the skin’s natural repair pathways it can promote a smoother surface, enhance elasticity and provide a refreshed, healthier look.

Who Can Use Rh-Polypeptide-66

Rh-Polypeptide-66 is gentle enough for most skin types. Dry, normal, combination, oily and mature skin can all benefit from its conditioning properties because it is lightweight and non-occlusive. Sensitive skin usually tolerates it as well thanks to its lab-purified production, though anyone with a history of peptide allergies should proceed with caution.

The peptide is produced through recombinant fermentation rather than animal extraction, making it suitable for vegans and vegetarians.

Current research has not flagged any specific risks for pregnant or breastfeeding women when Rh-Polypeptide-66 is used topically in cosmetic concentrations. That said this is not medical advice; anyone who is pregnant or nursing should run new skincare products past a qualified doctor before adding them to a routine.

Rh-Polypeptide-66 does not increase photosensitivity, so it can be applied morning or night. Standard daytime sun protection is still recommended to guard against routine UV damage. The ingredient layers well with most common skincare actives such as hyaluronic acid, niacinamide and antioxidants.

Potential Side Effects/Adverse Reactions

Responses to topical Rh-Polypeptide-66 differ from person to person. The points below outline potential side effects, yet they remain uncommon when the ingredient is formulated and used correctly.

  • Mild redness or irritation in very sensitive skin
  • Temporary stinging when applied to broken or compromised skin
  • Allergic contact dermatitis in individuals reactive to peptides or certain preservatives used alongside the ingredient
  • Reduced effectiveness if combined with highly acidic products which can destabilize the peptide

If any negative reaction occurs stop using the product and seek guidance from a healthcare professional.

Comedogenic Rating

Rating: 0 / 5

Rh-Polypeptide-66 is a large, water-soluble protein molecule that does not clog pores because it lacks the oily or waxy components that typically trigger comedones. It sits on the skin surface, carries out its conditioning role and rinses or wears off without leaving residue. Its lab-purified nature also means it is free from impurities that might otherwise cause congestion.

For these reasons the ingredient is generally considered suitable for acne-prone or breakout-prone skin.

One point to note is that the finished product formula matters; if a serum containing Rh-Polypeptide-66 is paired with heavy oils or rich butters the overall comedogenicity will depend on those added ingredients, not the peptide itself.

Summary

Rh-Polypeptide-66 is a lab produced version of the SIRT1 enzyme that helps condition skin by supporting natural repair pathways, leading to smoother texture, better elasticity and an overall healthier appearance. Because the peptide is water-based and highly purified it offers these benefits without adding weight or greasiness.

While peptides in general are gaining traction, Rh-Polypeptide-66 is still a niche addition compared with household staples like retinol or vitamin C. You will usually find it in premium anti-aging formulas aimed at boosting skin vitality.

Current data shows the ingredient is well tolerated with a very low risk of irritation or pore blockage, making it a safe choice for most skin types. As with any new skincare ingredient it is wise to perform a quick patch test before full use just to be on the safe side.

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