Peg-55 Hydrogenated Castor Oil: 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
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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 Peg-55 Hydrogenated Castor Oil?

Peg-55 Hydrogenated Castor Oil starts with plain castor oil that comes from the seeds of the Ricinus communis plant. The oil is first hydrogenated, a process that stabilizes it by turning many of its natural fatty acids into more solid forms. It is then treated with about 55 units of ethylene oxide, which attaches small chains that help the oil mix well with water. The finished ingredient is a waxy or pasty substance that acts much like a bridge between oil and water.

Castor oil itself has been used in beauty rituals for centuries because of its rich, glossy feel. In the middle of the twentieth century chemists learned that adding hydrogen and then ethylene oxide to castor oil made it far more versatile for modern formulations. Since then Peg-55 Hydrogenated Castor Oil has become a common helper ingredient in skin care and hair care.

You will often spot it on the label of face cleansers, micellar waters, shampoos, liquid soaps, makeup removers, sheet mask essences, and light lotions. These products rely on it to keep their oily and watery parts from separating and to lift away dirt, sweat, and makeup when you rinse.

Peg-55 Hydrogenated Castor Oil’s Cosmetic Benefits/Uses

Here is what this multitasker brings to a formula:

  • Cleansing: Its soap-like structure grabs onto oil and grime while still rinsing clean with water. This helps face washes and shampoos remove buildup without leaving a heavy residue.
  • Emulsifying: It keeps oil and water evenly blended so creams stay smooth, toners stay clear, and sprays stay uniform from the first pump to the last drop.

Who Can Use Peg-55 Hydrogenated Castor Oil

This ingredient is considered gentle enough for most skin types. Oily and combination skin appreciate its ability to lift away sebum without leaving a film, while dry skin benefits from the soft feel it leaves behind after rinsing. Sensitive skin usually tolerates it well, though anyone with a known castor oil allergy should steer clear because the base oil remains part of the molecule.

Peg-55 Hydrogenated Castor Oil is plant derived, so it is suitable for vegans and vegetarians. No animal by-products are involved in its manufacture.

Current research shows no specific risks for pregnant or breastfeeding women when the ingredient is used topically at the low levels found in cosmetics. This is not medical advice; anyone who is expecting or nursing should show the product label to a qualified health professional before use just to be safe.

The ingredient does not make skin more sensitive to sunlight, so it does not add any extra risk of sunburn. It also plays nicely with most other common skincare actives, making it a flexible choice in daily routines.

Potential Side Effects/Adverse Reactions

Individual responses to Peg-55 Hydrogenated Castor Oil vary. The points below describe potential side effects but they remain uncommon when the ingredient is formulated and used correctly.

  • Contact irritation – a temporary stinging or burning sensation, usually in very sensitive skin
  • Allergic contact dermatitis – redness, itching or small bumps in people allergic to castor oil derivatives
  • Eye discomfort – mild watering or stinging if a cleanser or makeup remover gets into the eyes
  • Greasy or coated feel – rare sensation of residue in those with extremely fine hair or very oily skin when the product is not rinsed thoroughly

If any of these reactions occur stop using the product and seek advice from a healthcare professional or dermatologist.

Comedogenic Rating

Rating: 1 out of 5

Peg-55 Hydrogenated Castor Oil is highly processed, water-soluble and used at low levels, which means it is far less likely to clog pores than raw plant oils. Its molecules are large and designed to rinse away cleanly, so they do not linger in follicles to create blockages. For these reasons the ingredient earns a 1, indicating a very low chance of triggering comedones.

This makes it generally suitable for acne-prone or breakout-prone skin, provided the rest of the formula is also low on pore-clogging ingredients.

As with any emulsifier, the overall product texture and rinse-off method play a role. A heavy balm packed with waxes will feel different from a watery micellar cleanser even if both contain Peg-55 Hydrogenated Castor Oil.

Summary

Peg-55 Hydrogenated Castor Oil acts mainly as a cleanser and an emulsifier. Its soap-like part grabs oils and dirt while its water-loving part helps the grime rinse away. At the same time it keeps oil and water evenly mixed so lotions stay smooth and cleansers stay stable.

The ingredient is a familiar face in modern formulations, turning up in everything from gentle face washes to clear toners. It is not the star of the show like vitamin C or retinol, but formulators reach for it often because it is dependable, vegan friendly and cost-effective.

Current safety data shows it is well tolerated by most skin types with a very low comedogenic rating. Still, every skin is unique, so it’s wise to patch test a new product that contains Peg-55 Hydrogenated Castor Oil before full-face use.

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