Stearyl Acetyl Glutaminate: 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 Stearyl Acetyl Glutaminate?

Stearyl Acetyl Glutaminate is a lab made ester created by joining stearyl alcohol, a fatty alcohol from vegetable oils, with N-acetyl glutamine, a modified form of the amino acid glutamine. By combining a long oil loving chain with a water friendly amino acid, chemists get a molecule that can mix well with both oils and water in skin care formulas.

The ingredient was first explored in the late 1990s when brands were looking for plant derived options that could soften skin without a heavy feel. Its balanced structure made it a hit for lightweight lotions and hair care products, and it soon spread to facial creams, sheet masks and creamy cleansers.

Manufacturing starts with the natural fatty alcohol stearyl alcohol, usually sourced from coconut or palm kernel oil. This is reacted with acetylated glutamine in a controlled setting to form a smooth white wax like material. After purification the finished ingredient is added to product bases while they are warm so it can melt in evenly.

You will most often spot Stearyl Acetyl Glutaminate in moisturizers, night creams, soothing masks, anti aging serums, leave in hair conditioners and gentle cleansers where a silky glide and lasting hydration are needed.

Stearyl Acetyl Glutaminate’s Cosmetic Benefits/Uses

In formulas this versatile ingredient works in a few key ways

  • Humectant: Attracts water from the environment and pulls it toward the skin surface helping to boost moisture levels and reduce the feeling of tightness
  • Skin conditioning: Forms a light protective layer that smooths rough patches making skin feel softer and more supple after use
  • Emollient: Fills in tiny gaps between skin cells creating a velvety finish and improving the spreadability of creams and lotions so they glide on without tugging

Who Can Use Stearyl Acetyl Glutaminate

This silky ester suits most skin types. Dry and mature skin appreciate its moisture attracting and softening ability. Combination and normal skin benefit from the light, non greasy feel. Even oily or acne prone skin usually tolerates it well because it does not create a heavy film, though those highly sensitive to fatty alcohol derivatives may wish to keep an eye on how their skin responds.

The ingredient is produced from plant sourced stearyl alcohol and lab fermented amino acids, so it is considered suitable for vegans and vegetarians. Always check the full product label to confirm other components align with your preferences.

No published data flags Stearyl Acetyl Glutaminate as a concern for women who are pregnant or breastfeeding. That said, this information is not medical advice and anyone expecting or nursing should review any skincare formula with a medical professional to be extra safe.

The molecule does not make skin more prone to sun sensitivity, so it can be used day or night without elevating the risk of UV related irritation. Standard sun protection practices still apply when using any daytime skincare routine.

Potential Side Effects/Adverse Reactions

Responses to topical Stearyl Acetyl Glutaminate can differ from person to person. The points below outline possible side effects, yet most users will not notice any of them when the ingredient is included at appropriate levels in a well formulated product.

  • Mild redness or stinging on very sensitive skin
  • Rare allergic contact dermatitis presenting as itching or small bumps
  • Temporary clogged pores in individuals extremely reactive to fatty alcohol derivatives
  • Eye irritation if the product accidentally enters the eyes

If any unwanted reaction occurs stop using the product and seek advice from a qualified healthcare provider.

Comedogenic Rating

Rating: 1 out of 5. Stearyl Acetyl Glutaminate contains a long fatty chain yet it is esterified with a lightweight amino acid, which keeps it from building up heavily inside pores. Tests on similar fatty acid esters show a very low tendency to trigger comedones, especially at the modest percentages used in skin care. Because it melts easily into formulas and leaves only a thin, breathable film, it is generally considered suitable for acne prone or breakout prone skin. As with any ingredient, the final product’s full recipe and texture play a role, so very occlusive creams may still pose a pore clogging risk for some users.

Summary

Stearyl Acetyl Glutaminate acts as a humectant, skin conditioner and emollient. Its water friendly amino acid segment pulls moisture toward the skin while the stearyl portion smooths over rough areas, fills micro gaps between cells and gives creams a silky glide. This dual nature helps products feel light yet still deliver lasting softness.

The ingredient enjoys moderate popularity; it is not as common as glycerin or shea butter but shows up regularly in mid to high end lotions, masks and leave in hair treatments where a refined, weightless finish is desired.

Overall safety data is reassuring with low irritation reports and a negligible comedogenic score. Still, everyone’s skin is unique so it is smart to patch test any new product that lists Stearyl Acetyl Glutaminate before applying it to a larger area.

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