Acetylated Cetyl Hydroxyprolinate: 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 23, 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 Acetylated Cetyl Hydroxyprolinate?

Acetylated Cetyl Hydroxyprolinate is a specialty ester formed from the natural amino acid L-proline and cetyl alcohol, then lightly acetylated to boost skin affinity. By attaching a 16-carbon cetyl chain to the proline backbone, chemists created a molecule that carries both water-loving and oil-loving portions, allowing it to slip easily into the skin’s surface layers. First introduced in the late 1990s as formulators searched for gentler alternatives to heavy occlusives, it has since become a quiet staple in modern moisturizing blends.

The ingredient is produced through a two-step process. In step one, L-proline reacts with cetyl alcohol in the presence of an activating agent to form a proline-cetyl ester. Step two adds a modest acetyl group, which smooths the molecule’s polarity and improves texture. The finished material appears as a soft, pale wax that melts near skin temperature, making it simple to incorporate into the oil phase of creams and lotions.

Because of its balanced structure, Acetylated Cetyl Hydroxyprolinate shows up in a wide range of leave-on products. You will most often see it in facial moisturizers, anti aging serums, night creams, nourishing sheet masks, body butters, lip balms and hand treatments where lasting softness is a priority.

Acetylated Cetyl Hydroxyprolinate’s Cosmetic Benefits/Uses

This multitasking ester earns its spot on an ingredient list by offering the skin two core benefits

  • Skin Conditioning: The proline portion attracts and binds water while the cetyl chain reinforces the skin’s lipid barrier, helping the surface feel smoother, more supple and better hydrated over time.
  • Emollient: Its melt-on-contact texture fills in microscopic gaps between corneocytes, softening rough patches and lending creams a silky, non-greasy finish that improves spreadability.

Who Can Use Acetylated Cetyl Hydroxyprolinate

This silky ester suits most skin types including dry, normal and combination because it adds moisture without leaving a heavy greasy film. Oily or very acne prone complexions generally tolerate it well too though extremely congestion-prone users might prefer lighter options since any rich lipid can occasionally sit on the surface and trap oil.

The molecule is typically produced from plant-fermented L-proline and sustainably sourced cetyl alcohol so formulations containing it are usually considered vegetarian and vegan friendly. As always, check the brand’s sourcing statement if strict animal-free status is essential.

No published data shows that Acetylated Cetyl Hydroxyprolinate poses a particular risk to pregnant or breastfeeding women. Still, this is not medical advice and anyone who is expecting or nursing should run any skincare routine past a doctor to be safe.

The ingredient does not absorb UV light and is not known to cause photosensitivity so it can be used day or night without raising sun sensitivity.

Potential Side Effects/Adverse Reactions

Responses to topical Acetylated Cetyl Hydroxyprolinate vary from person to person. The points below outline potential side effects but most users will not experience them when the ingredient is correctly formulated and used as directed.

  • Mild redness or stinging on very sensitive skin
  • Contact dermatitis in individuals allergic to fatty alcohol derivatives
  • Temporary clogged pores or small surface bumps in those highly prone to comedones
  • Interaction-related irritation if layered with strong actives such as high-level retinoids or exfoliating acids

If any of these effects occur stop use immediately and consult a healthcare professional.

Comedogenic Rating

Rating: 2 / 5

Acetylated Cetyl Hydroxyprolinate carries a long fatty chain that can sit on the skin, yet its bulky ester structure keeps it from sliding deeply into pores which limits its clogging potential. Most users, even those with combination or mildly oily skin, find it light enough for daily wear although very acne prone individuals may prefer leaner formulas.

Its low melting point lets it spread thinly, reducing the chance of pore blockage compared with heavier waxes. However, in rich balms or when layered with multiple occlusives it could contribute to congestion so product context matters.

Bottom line: generally suitable for breakout prone skin but not the very easiest option if you are extremely susceptible to clogged pores.

Summary

Acetylated Cetyl Hydroxyprolinate is a dual action ingredient that conditions skin and acts as an emollient. The proline part draws moisture toward the surface while the cetyl chain slips into the lipid matrix to smooth rough edges and reinforce barrier function. A light acetyl tweak trims greasiness so the finished ester melts on contact leaving a silky feel rather than a heavy film.

It is more of a quiet supporting player than a headline star yet formulators value it for the way it upgrades texture in moisturizers serums and body butters without overshadowing key actives. Safety data shows low irritation and allergy risk for the vast majority of users, making it a dependable pick in modern skin care. As with any new product do a small patch test first to confirm personal compatibility.

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