Magnesium Peg-3 Cocamide Sulfate: 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: July 1, 2025
Share:
Inside this article:

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 Magnesium Peg-3 Cocamide Sulfate?

Magnesium Peg-3 Cocamide Sulfate is a surfactant created by reacting coconut-derived fatty acids with ethylene oxide to form a PEG-3 cocamide, then sulfonating the molecule and neutralizing it with magnesium salts. The result is a water-soluble compound that carries both oil-loving and water-loving parts, making it highly effective at binding grime and rinsing it away. It emerged in the late twentieth century when formulators looked for gentler, plant-based cleansers to replace harsher sulfates in shampoos and body washes. Today the ingredient is produced in large-scale reactors where temperature, pressure and pH are carefully controlled to ensure consistent chain length and purity. You will most often spot it in liquid shampoos, shower gels, facial cleansers, bubble baths and occasionally in clarifying scalp treatments where rich foam and easy rinse-off are key.

Magnesium Peg-3 Cocamide Sulfate’s Cosmetic Benefits/Uses

The ingredient serves a single, but important, role in personal care formulas.

Cleansing: As a mild surfactant it lowers surface tension so water can mix with oils and dirt, lifting them from skin or hair and allowing them to be washed away. It also contributes to a rich, stable lather that enhances the sensory feel of products and helps distribute active ingredients evenly during use.

Who Can Use Magnesium Peg-3 Cocamide Sulfate

This surfactant is generally well tolerated by most skin types, including normal, oily and combination skin. Dry or very sensitive skin may sometimes find foaming cleansers a little stripping, so formulas that pair the ingredient with extra moisturizers are a better choice for those groups.

Because it is derived from coconut oil and the finishing steps are synthetic, it is free of animal by-products which makes it suitable for both vegans and vegetarians.

No specific warnings exist for use during pregnancy or while breastfeeding. Still, this is not medical advice and anyone who is pregnant or nursing should show the full ingredient list of their personal care products to a qualified healthcare provider for peace of mind.

The ingredient does not make skin more sensitive to sunlight so it is not considered photosensitizing. It also plays well with most other common cleanser ingredients, which means it rarely causes formulation conflicts.

Potential Side Effects/Adverse Reactions

Reactions to topical Magnesium Peg-3 Cocamide Sulfate differ from person to person. The points below list potential concerns yet they are uncommon when products are well formulated and used as directed.

  • Mild skin dryness or tightness
  • Transient redness on very sensitive skin
  • Eye irritation if product accidentally gets into the eyes
  • Rare allergic contact dermatitis in individuals with a specific sensitivity to coconut derived surfactants

If any irritation or discomfort occurs stop using the product and seek advice from a healthcare professional.

Comedogenic Rating

Rating: 1/5 – Magnesium Peg-3 Cocamide Sulfate is a highly water-soluble surfactant that rinses clean without leaving behind oily residues that could block pores. Because it does not sit on skin or create an occlusive film, the likelihood of it triggering blackheads or breakouts is very low. It is generally considered suitable for acne-prone skin unless an individual has a rare sensitivity to coconut-derived cleansers. The only caveat is that every formula is different, so the overall comedogenicity of a finished product depends on the complete ingredient list, not just this single component.

Summary

Magnesium Peg-3 Cocamide Sulfate is a plant-derived cleansing agent valued for its ability to break up oil and dirt then rinse away easily, all while creating a satisfying lather. Its popularity sits in the middle of the pack: common enough to appear in many mainstream shampoos and body washes yet not as ubiquitous as classic sodium laureth sulfate. Safety data show it is low-irritation for most users and non-comedogenic, making it a dependable choice across skin types. As with any new personal care product, give your skin a chance to adjust by performing a quick patch test to ensure compatibility.

Was this article helpful?
More from Glooshi:
ADVERTISEMENT
Get all our top headlines in beauty.
Delivered right to your inbox each week. Zero spam, all goodness, opt-out at anytime.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Get the latest beauty news, top product recommendations & brand-exclusive discount codes direct to your inbox.
Send good feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Send bad feedback:

All feedback is greatly appreciated, anonymous, and will be used to improve the quality of our articles.

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Search