What Is Sodium Undecylenoamphopropionate?
Sodium Undecylenoamphopropionate is a water-soluble surfactant that comes from undecylenic acid, an oil naturally present in castor seeds. Through a series of reactions, chemists join undecylenic acid with a small amino acid-like molecule, then neutralize the mixture with sodium to create this salt form. The result is a gentle, skin-friendly ingredient that attracts both oil and water, letting it lift dirt without stripping moisture.
The ingredient first appeared in personal care labs in the late 1970s, when formulators were looking for milder alternatives to traditional soaps. Its built-in fatty chain helps protect skin and hair while its charged head boosts foam, making it popular in sulfate-free cleansers. Today it shows up in face washes, micellar waters, baby shampoos, clarifying scalp scrubs, foaming bath products and even some sheet mask essences.
Sodium Undecylenoamphopropionate’s Cosmetic Benefits/Uses
In formulas, this multitasker brings several advantages
- Cleansing: Breaks up makeup, excess oil and daily grime so they rinse away easily, leaving skin and hair feeling fresh but not squeaky
- Foaming: Produces a rich creamy lather that improves the sensory feel of a product, helping users spread it evenly
- Hair Conditioning: Deposits a light, smooth film on strands, reducing static and making hair easier to detangle
- Foam Boosting: Enhances and stabilizes bubbles created by other surfactants so the foam lasts longer during use
Who Can Use Sodium Undecylenoamphopropionate
This ingredient is generally well tolerated by all skin types, including oily, dry, combination and sensitive. Its mild surfactant nature means it cleans without upsetting the skin’s natural barrier so even reactive complexions usually handle it well. There are no specific groups that need to steer clear, though anyone with a known allergy to castor-derived materials should proceed with caution.
Sodium Undecylenoamphopropionate is plant sourced from castor seeds and does not involve animal derivatives or testing, making it suitable for vegans and vegetarians.
Current safety data indicate no issues for pregnant or breastfeeding users when the ingredient is used topically at the low levels found in finished cosmetics. This is not medical advice and anyone who is pregnant or nursing should clear new products with a healthcare professional first.
The ingredient is not known to cause photosensitivity, so it will not make skin more prone to sunburn. Normal daily sun protection is still recommended for overall skin health.
Potential Side Effects/Adverse Reactions
Reactions to topical Sodium Undecylenoamphopropionate can vary from one person to the next. The effects listed below are possible but not expected for most users when the ingredient is used correctly in a finished product.
- Mild redness or itching – usually temporary and resolves after rinsing
- Stinging in the eyes – can occur if the cleanser accidentally gets into the eyes
- Dry or tight feeling – more likely if multiple foaming agents are present in the same formula
- Allergic contact dermatitis – extremely rare but possible if someone is sensitive to castor-derived substances
If any persistent discomfort or rash develops discontinue use and seek advice from a medical professional.
Comedogenic Rating
Rating: 0 / 5
Sodium Undecylenoamphopropionate is a fully water-soluble surfactant that rinses off cleanly and leaves no oily residue on the skin. Because it does not stay behind to clog pores or mix with sebum, it earns the lowest possible comedogenic score.
This makes the ingredient suitable for people prone to acne or frequent breakouts.
One point to note: if the final product also contains occlusive oils or heavy butters, the overall formula could still feel pore-clogging even though this specific surfactant is not.
Summary
Sodium Undecylenoamphopropionate is a gentle castor-derived surfactant that cleanses, boosts foam and leaves a light conditioning film on hair. Its amphoteric structure lets one end grab on to dirt and oil while the other mixes with water so everything washes away easily. The same molecular design stabilizes bubbles, creating a rich lather and a smoother after-feel.
Although it is not as famous as ingredients like sodium cocoyl isethionate, formulators appreciate its mildness and are adding it to more sulfate-free cleansers, baby shampoos and micellar waters.
Current safety reviews show it is low risk for irritation or allergy at the levels used in cosmetics. Even so it is wise to patch test any new product to rule out personal sensitivities.