Sodium Isostearoyl Lactylate: 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 Sodium Isostearoyl Lactylate?

Sodium Isostearoyl Lactylate is a salt formed from lactic acid and isostearic acid, both of which usually come from plant sources such as corn sugar and vegetable oil. Although it sounds complex its roots are quite natural. It first showed up in the food world as an emulsifier that helped oils and water mix, then formulators noticed it could do the same for skin care. The ingredient is made through a two step process: lactic acid is combined with isostearic acid to create an ester, then the ester is neutralized with a small amount of sodium to give the finished powder or paste.

Because it balances oil and water it appears in many product types. You will find it in facial cleansers that need a gentle foam, moisturizers that must stay smooth, masks that combine clay and oils, sunscreens that keep the active filters evenly spread and lightweight serums that should not feel greasy.

Sodium Isostearoyl Lactylate’s Cosmetic Benefits/Uses

This ingredient mainly serves two helpful jobs in skin care formulas

  • Cleansing – Its mild surfactant action lifts away dirt and excess oil without stripping the skin so products feel gentle yet effective
  • Emulsifying – It binds water and oil into a stable blend which keeps creams from separating and gives a smooth, easy to spread texture

Who Can Use Sodium Isostearoyl Lactylate

Because it is a mild cleanser and stabilizer most skin types tolerate Sodium Isostearoyl Lactylate well. Oily and combination skin appreciate the light cleansing action while dry and sensitive skin benefit from its gentle nature that does not strip moisture. Only those with a known allergy to lactic acid derivatives or isostearic acid should avoid it.

The ingredient is typically sourced from corn sugar and vegetable oil so it is suitable for both vegans and vegetarians. Anyone following a cruelty free routine should still verify that the finished product has not been tested on animals.

No published data link Sodium Isostearoyl Lactylate to problems during pregnancy or breastfeeding. It is regarded as low risk, yet this is not medical advice and anyone who is pregnant or nursing should show their skincare lineup to a healthcare professional for personalized guidance.

The molecule does not make skin more sensitive to sunlight so it is not considered photosensitizing. It also plays well with most actives, fragrances and preservatives which makes it a flexible option inside many formulas.

Potential Side Effects/Adverse Reactions

  • Skin irritation some users may notice mild redness or itching, especially on compromised or highly sensitive skin
  • Contact allergy in rare cases an allergic response such as a rash or swelling can occur
  • Eye discomfort cleansers containing the ingredient may cause stinging if product accidentally enters the eyes
  • Dryness or tightness very high concentrations can disturb the skin barrier leading to a temporary dry feel

If any of these reactions develop stop using the product and consult a healthcare professional for further advice.

Comedogenic Rating

Sodium Isostearoyl Lactylate has a comedogenic rating of 1. The molecule is relatively large and water soluble so it does not readily lodge inside pores or harden in sebaceous filaments. Most formulas also use it at low levels which further limits the chance of clogging. For these reasons it is generally suitable for skin prone to acne or breakouts. The only caveat is that in very rich creams combined with heavy oils an overall formula could still feel occlusive, though the ingredient itself remains low risk.

Summary

Sodium Isostearoyl Lactylate serves mainly as a gentle cleanser and an effective emulsifier. Its amphiphilic structure has both water loving and oil loving portions which lets it lift away grime while also holding water and oil together inside a stable cream or lotion. The ingredient enjoys moderate popularity with formulators who want plant derived multifunctional agents, yet it is not as widely recognized by shoppers as bigger name surfactants.

Safety data show it to be low irritation, non photosensitizing and vegan friendly so most people can use it with confidence. Still, skin can be unpredictable so it is smart to do a patch test when trying any new product that contains Sodium Isostearoyl Lactylate.

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