C16-17 Isoalcohols: 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 24, 2025
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All information on this page is verified using The Personal Care Products Council's (PCPC) INCI database. Our ingredient analyses are based exclusively on PCPC's technical data to ensure accuracy and reliability.

What Is C16-17 Isoalcohols?

C16-17 Isoalcohols is a lab made blend of fatty alcohols that each carry either 16 or 17 carbon atoms arranged in a branched pattern. These molecules are cousins to the straight chain fatty alcohols that have been used in skin care since the 1950s, yet their branched shape gives them a lighter feel and a smoother finish on skin.

Most suppliers start with natural or petroleum based fatty acids, turn them into aldehydes by the oxo process, then add hydrogen to form the final alcohols. Careful control of temperature and pressure lets chemists create just the right mix of 16 and 17 carbon pieces plus the side branches that set isoalcohols apart.

Because the material spreads easily and leaves behind a soft touch, formulators slip it into many leave-on products. You will often see it in daily moisturizers, night creams, facial oils, body lotions, sunscreens, stick balms, makeup primers and even some hair conditioners where a non-greasy slip is needed.

C16-17 Isoalcohols’s Cosmetic Benefits/Uses

Here is how C16-17 Isoalcohols helps a formula perform and feel its best

  • Skin Conditioning: The ingredient coats the surface of skin with a thin flexible film that smooths rough patches, boosts softness and can reduce the look of flaky spots
  • Emollient: Its branched chains fill tiny gaps between skin cells which improves moisture retention and gives products a silky glide without a heavy or oily afterfeel

Who Can Use C16-17 Isoalcohols

C16-17 Isoalcohols tends to suit most skin types including dry, normal and combination skin thanks to its light non greasy finish. Oily or very acne prone users usually tolerate it as well, though those who are extremely sensitive to fatty alcohols might prefer to monitor how their skin responds after a few uses.

The ingredient is synthetic and contains no animal derived raw materials so it is generally considered suitable for both vegans and vegetarians.

No specific warnings exist for pregnant or breastfeeding women. Current safety assessments have not flagged any reproductive or developmental concerns, yet this is not medical advice and anyone who is pregnant or nursing should confirm product choices with a qualified healthcare provider.

C16-17 Isoalcohols does not make skin more sensitive to sunlight, so routine daytime use requires no extra sun precautions beyond the daily SPF experts already recommend.

Potential Side Effects/Adverse Reactions

Responses to topical C16-17 Isoalcohols can differ from person to person. The points below outline potential effects that are possible yet unlikely for most users when the ingredient is included at normal cosmetic levels.

  • Mild skin irritation such as transient stinging or warmth
  • Localized redness or itching in those with very reactive skin
  • Contact dermatitis in individuals allergic to fatty alcohol structures
  • Temporary clogged pores or breakouts for users who are highly acne prone
  • Eye irritation if the product accidentally gets into the eyes

If any of these reactions occur discontinue use and consult a healthcare professional if symptoms persist or worsen.

Comedogenic Rating

Rating: 1/5 (low likelihood of clogging pores)

The branched shape of C16-17 Isoalcohols prevents the molecules from stacking tightly on the skin so they are less likely to trap oil inside pores. Formulas usually include it at moderate levels alongside water or light silicones which further keeps the clogging risk down.

Most people prone to acne or breakouts can use products with this ingredient without problems, though highly reactive skin should still monitor its response.

Remember that a product’s overall pore-clogging potential depends on the whole ingredient list, texture and how often it is applied, not just on one component.

Summary

C16-17 Isoalcohols serves as a skin conditioning and emollient helper, smoothing rough patches, filling tiny gaps between cells and leaving a soft non greasy finish that locks in moisture.

It is not a household name but formulators value its silky slip, so you will spot it in a growing number of lotions, sunscreens, primers and balms that aim for a lightweight feel.

Safety assessments rate it as low risk with minimal irritation or sensitization concerns. Even so, every skin is unique so it is wise to patch test any new product that features C16-17 Isoalcohols before applying it more broadly.

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