Glyceryl Isostearate/Myristate: 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 27, 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 Glyceryl Isostearate/Myristate?

Glyceryl Isostearate/Myristate is a fatty ester created when glycerin, a naturally occurring humectant found in plant oils, is combined with isostearic and myristic acids derived from renewable vegetable fats. Chemically it is an ester blend that links glycerol with two different long-chain fatty acids, giving it a balanced profile of lightness and richness. Its development traces back to the 1980s when formulators started pairing various fatty acids with glycerin to improve skin feel in lotions and color cosmetics. By tweaking the acid mix they discovered a texture enhancer that spreads easily yet leaves a soft, cushiony finish.

Manufacturing begins with food-grade glycerin that is heated and reacted with purified isostearic and myristic acids under controlled temperatures. Catalysts speed up the esterification, water is removed, then the mixture is refined and filtered to yield a pale, odorless liquid-to-soft solid. Because both starting materials can be sourced from coconut, palm or rapeseed oils, the final ingredient is readily available and fits current clean beauty trends.

You will most often spot Glyceryl Isostearate/Myristate in face creams, body lotions, sunscreens, cleansing balms, sheet mask essences, anti-aging serums and makeup like foundation sticks or cream blush where a smooth glide and lasting moisture are needed.

Glyceryl Isostearate/Myristate’s Cosmetic Benefits/Uses

Its multitasking nature makes it valuable across many product categories.

  • Skin Conditioning: Helps keep skin soft and flexible by forming a light film that slows water loss
  • Emollient: Fills in microscopic gaps between skin cells to smooth rough patches leaving a silky afterfeel without greasiness
  • Cleansing: Loosens and lifts oil-based impurities allowing them to rinse away gently which is why it appears in balm and milk cleansers
  • Emulsifying: Stabilizes mixtures of oil and water so creams stay uniform preventing separation during shelf life

Who Can Use Glyceryl Isostearate/Myristate

This silky ester suits most skin types including dry, normal and combination because it delivers lightweight moisture without leaving a greasy film. Oily or acne-prone users generally tolerate it well though very clog-prone skin should still monitor how their complexion responds since any lipid can feel too rich for some. Sensitive skin usually finds it gentle as it is free of fragrance and known irritants.

The ingredient is produced from plant-based glycerin and vegetable fatty acids so it is suitable for vegetarians and vegans provided the finished formula does not contain other animal-derived components.

No research links Glyceryl Isostearate/Myristate to hormonal disruption or developmental concerns so products containing it are considered safe for those who are pregnant or breastfeeding. This is not medical advice and anyone who is pregnant or nursing should discuss all skincare products with a qualified healthcare professional before use.

It does not increase photosensitivity, meaning it will not make skin more prone to sunburn. As always wearing daily sunscreen remains an essential step for overall skin health.

Potential Side Effects/Adverse Reactions

Reactions to topical Glyceryl Isostearate/Myristate vary from person to person. The points below outline potential side effects yet they are uncommon when the ingredient is properly formulated and used as directed.

  • Mild irritation slight redness or stinging on very reactive skin
  • Contact dermatitis rare allergic response marked by itching or rash
  • Clogged pores possible in individuals highly prone to comedones especially if layered with heavy occlusives

If any adverse effect occurs discontinue use and consult a healthcare professional or dermatologist.

Comedogenic Rating

Rating: 2/5. Glyceryl Isostearate/Myristate sits on the lower end of the comedogenic scale because its bulky ester structure largely stays on the skin surface rather than seeping deep into pores. The myristate portion does bring a small risk of clogging for very oil-rich complexions which keeps the score from being a 0 or 1. Overall it is usually suitable for acne-prone users who tolerate lightweight fatty esters, though those with stubborn breakouts may prefer to limit how often they layer it with other heavy lipids. Formulation level and the presence of occlusive ingredients in the same product can raise or lower clogging potential so the full formula always matters.

Summary

Glyceryl Isostearate/Myristate conditions skin, works as an emollient, helps cleanse and stabilises oil-water mixtures. It does this by forming a fine flexible film that reduces moisture loss, filling in rough spots for a smooth feel, gently dissolving makeup and oils and anchoring emulsions so lotions stay creamy over time.

The ingredient is a quiet workhorse rather than a headline act: not as famous as hyaluronic acid or shea butter yet common enough that you will spot it in everything from daily moisturisers to sunscreens and stick foundations because chemists like its balanced texture.

Safety data show very low irritation and allergy rates so most people can use it with confidence. As with any new cosmetic, do a small patch test first if you have sensitive or reactive skin to confirm personal tolerance.

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