Ingredient review

Undecylenamidopropylamine Oxide

INCI: UNDECYLENAMIDOPROPYLAMINE OXIDE

A gentle, low-irritation surfactant that helps create a rich lather and improve product texture without stripping the skin.

beautyskincaresurfactant

In plain English

This ingredient is a mild cleansing agent that helps create foam and thicken the texture of cleansers and shampoos. It is derived from undecylenic acid, which comes from castor oil, and is known for being gentle on skin and eyes. Unlike harsher sulfates, it cleans without stripping away too much moisture, making it a popular choice for sensitive skin and baby products.

Review score

Safety, usefulness, and evidence

4.0Good

4.0/ 5

Potentially useful with some tradeoffs

The evidence base is useful, but some claims depend heavily on the formula.

Risk flags are low for most users, though the finished product can still irritate.

Source: semi synthetic
Evidence: moderate
Irritation: low
Clogging risk: low

How reviews are scored

Quick decision guide

Useful, but context matters

Undecylenamidopropylamine Oxide is generally a lower-concern ingredient when the full formula suits your skin.

Plain-English read

Treat this as a practical screening step before you compare products that contain this ingredient.

Step 1Start with the score, then check the irritation and clogging risk before judging Undecylenamidopropylamine Oxide.
Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
Step 3If a product stings, breaks you out, or worsens irritation, judge the finished formula and stop using it even if the ingredient scores well.

Score terms in plain English

Irritation risk

low

Less likely to sting, burn, or bother most users, though sensitive skin can still react.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

moderate

There is useful support, but formula details and claim strength still matter.

What it is

Undecylenamidopropylamine Oxide is an amine oxide surfactant, a semi-synthetic compound made by reacting undecylenic acid (from castor oil) with other chemicals. It functions as a foam booster, viscosity builder, and mild cleansing agent in rinse-off personal care products.

How it works

In a cosmetic product, this ingredient reduces the surface tension of water, allowing dirt and oil to be lifted away from the skin or hair. It also helps create a stable, creamy foam and thickens the product's consistency, improving the sensory experience during cleansing.

Pros

Gentle on skin

This surfactant has a low irritation profile, making it suitable for sensitive skin and even baby washes, unlike harsher sulfates that can cause redness or tightness.

Improves product feel

It boosts foam and thickens the formula, giving cleansers and shampoos a rich, creamy texture that many users find pleasant and effective.

Cons and cautions

Limited cleansing power

While gentle, it may not thoroughly remove heavy makeup, waterproof sunscreen, or excess oil, requiring a double-cleansing step for some users.

Potential for mild dryness

In high concentrations or with very frequent use, it can still cause slight dryness, especially for those with already dry or compromised skin barriers.

Best for

People with sensitive or easily irritated skin looking for a mild cleanser
Those who prefer sulfate-free or low-foam cleansing products

Use caution if

Individuals with known allergies to amine oxides or castor oil derivatives (rare)

Usage tips

Use in rinse-off products like face washes and shampoos; not typically found in leave-on formulations.

Pair with other mild surfactants (e.g., cocamidopropyl betaine) to balance cleansing power and gentleness.

If you have very dry skin, follow up with a moisturizer after cleansing to maintain hydration.

Safety summary

Undecylenamidopropylamine Oxide is considered safe for use in rinse-off cosmetics at typical concentrations. It has low irritation and sensitization potential, and no significant health concerns have been identified in regulatory reviews. As with any ingredient, patch testing is recommended for those with very sensitive skin.

Research notes

Research on amine oxide surfactants, including undecylenamidopropylamine oxide, indicates they are mild and well-tolerated. Studies show they have low eye and skin irritation compared to anionic surfactants like sodium lauryl sulfate. However, specific clinical data on this exact compound is limited, and most safety assessments rely on broader surfactant class data.

Common label clues

Typical concentration: 1–10% in rinse-off products
Regulatory status: Approved for use in cosmetics in the EU, US, and other major markets. No known restrictions at typical use levels.
Common uses: Facial cleansers, Body washes, Shampoos, Baby care products
Environmental note: Derived from castor oil (a renewable resource) and considered readily biodegradable, though full environmental impact depends on formulation and disposal.

Good to know

This ingredient is often listed near the middle of an ingredient list, indicating moderate concentration.
It is considered biodegradable and more environmentally friendly than some traditional surfactants.

Common questions

What is Undecylenamidopropylamine Oxide in beauty products?

What does Undecylenamidopropylamine Oxide do in a beauty product?

Is Undecylenamidopropylamine Oxide safe for most people?

Who should be careful with Undecylenamidopropylamine Oxide?

Individuals with known allergies to amine oxides or castor oil derivatives (rare)

Research sources

Cosmetic Ingredient Review (CIR) - Safety Assessment of Amine OxidesOpen PubChem - Undecylenamidopropylamine OxideOpen European Chemicals Agency (ECHA) - Substance InformationOpen

Ingredient reviews are educational and are not medical advice. Patch test new products and ask a licensed clinician about persistent irritation, allergies, pregnancy-specific questions, or diagnosed skin conditions.