Glyceryl Isostearate
1. What is Glyceryl Isostearate & How is it Used in Cosmetics?
INCI: Glyceryl Isostearate is an ester of glycerin and isostearic acid. It is used as a skin-conditioning emollient and co-emulsifier in creams, lotions, and sunscreens. It improves skin feel by reducing greasiness, adding slip, and enhancing the stability of emulsions. Derived from vegetable glycerin and fatty acids, it is biodegradable and considered safe for cosmetic use by the Cosmetic Ingredient Review Expert Panel [1][2].
2. Technical Details & Characteristics
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Appearance: Pale yellow to off-white solid or waxy paste
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Function: Emollient, co-emulsifier, skin-conditioning agent
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Form Compatibility: Dispersible in oils; functions in both O/W and W/O emulsions
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Typical Use Levels: 1–5% in emulsions
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Safety: Reviewed within the CIR Glyceryl Monoesters group; found safe as used in current concentrations and applications [1]
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Sustainability: Derived from renewable plant oils; fully biodegradable
3. How to Formulate (Independent Formulators)
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Add to: Oil phase of emulsions; melt with other lipids before emulsification
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For texture: Increases viscosity and creaminess; improves spreadability
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pH Range: Stable across typical cosmetic ranges (4–8)
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Compatibility: Works well with other fatty alcohols, esters, triglycerides, and most emulsifier systems
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Processing Temperature: Can tolerate heating to 75–80 °C
4. Ready-to-Use Example Formulas (100 g batches)
A. Rich Night Cream (O/W Emulsion)
| Phase | Ingredient | % | g | Function |
|---|---|---|---|---|
| A – Water Phase | Deionized Water | 63.00 | 63.00 | Solvent |
| Glycerin | 4.00 | 4.00 | Humectant | |
| Sodium Hyaluronate (1% sol.) | 2.00 | 2.00 | Hydration | |
| B – Oil Phase | Glyceryl Isostearate | 5.00 | 5.00 | Co-emulsifier, emollient |
| Caprylic/Capric Triglyceride | 10.00 | 10.00 | Lightweight emollient | |
| Shea Butter | 6.00 | 6.00 | Rich emollient | |
| Polyglyceryl-6 Stearate | 4.00 | 4.00 | Primary emulsifier | |
| C – Cool Down | Phenoxyethanol & Ethylhexylglycerin | 1.00 | 1.00 | Preservative |
| Fragrance (optional) | 0.50 | 0.50 | Scent | |
| Citric Acid Solution | q.s. | q.s. | pH 5.5–6.0 |
Method: Heat phases A and B to ~75 °C, add B into A with high shear, homogenise, cool with gentle stirring, add cool-down ingredients below 40 °C, adjust pH, fill.
B. Silky Face Oil Serum (Anhydrous)
| Ingredient | % | g | Function |
|---|---|---|---|
| Glyceryl Isostearate | 20.00 | 20.00 | Lightweight emollient |
| Squalane | 40.00 | 40.00 | Skin-conditioning |
| Rosehip Oil | 30.00 | 30.00 | Nourishing oil |
| Tocopherol (Vitamin E) | 1.00 | 1.00 | Antioxidant |
| Caprylic/Capric Triglyceride | 9.00 | 9.00 | Texture modifier |
Method: Blend at room temperature until uniform; fill into airless packaging.
C. Lightweight Sunscreen Lotion (O/W)
| Phase | Ingredient | % | g | Function |
|---|---|---|---|---|
| A – Water Phase | Deionized Water | 55.00 | 55.00 | Solvent |
| Aloe Vera Juice | 5.00 | 5.00 | Soothing | |
| B – Oil Phase | Glyceryl Isostearate | 3.00 | 3.00 | Co-emulsifier |
| C12-15 Alkyl Benzoate | 10.00 | 10.00 | Emollient, improves UV filter spread | |
| Zinc Oxide (non-nano) | 15.00 | 15.00 | Mineral UV filter | |
| Polyglyceryl-4 Caprate | 4.00 | 4.00 | Primary emulsifier | |
| C – Cool Down | Phenoxyethanol & Ethylhexylglycerin | 1.00 | 1.00 | Preservative |
| Citric Acid Solution | q.s. | q.s. | pH 6.0 |
Method: Disperse zinc oxide in oil phase, heat both phases to ~75 °C, emulsify, homogenise, cool to below 40 °C, add preservatives, adjust pH, fill.
5. Where You’ll See It
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Rich night creams and moisturisers
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Face oils and serums for enhanced slip
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Sunscreens and BB creams
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Hair conditioners for added smoothness
JustGlow Loves It Because…
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Adds luxurious, silky skin feel without heaviness
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Functions as both emollient and emulsifier
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CIR-reviewed for safety and mildness
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Versatile across skincare, suncare, and haircare formulas
References
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Fiume MM, et al. Safety Assessment of Glyceryl Monoesters as Used in Cosmetics. Int J Toxicol. 2007;26(Suppl 3):1–30. doi:10.1080/10915810701663100.
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Cosmetic Ingredient Review Expert Panel. Amended Safety Assessment of Glyceryl Monoesters. CIR Final Report, 2020.
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Goddard ED, Gruber JV. Principles of Polymer Science and Technology in Cosmetics and Personal Care. CRC Press, 1999.
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Huber B, et al. The influence of emulsifiers on the skin feel of cosmetic emulsions. Int J Cosmetic Science. 2014;36(4):347–354. doi:10.1111/ics.12137.