Ingredient review
Methyl Undecenoyl Leucinate
INCI: Methyl Undecenoyl Leucinate
A mild, amino-acid-based surfactant that cleanses without stripping the skin’s natural moisture barrier.
In plain English
Methyl Undecenoyl Leucinate is a gentle cleansing ingredient made from leucine, an amino acid found in proteins. It helps remove dirt, oil, and makeup without leaving your skin feeling tight or dry. Unlike harsher soaps, it respects your skin’s natural barrier, making it a favorite for sensitive or dry skin types.
Review score
Safety, usefulness, and evidence
Strong fit for many routines
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
Quick decision guide
Easy yes for most routines
Methyl Undecenoyl Leucinate 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 Methyl Undecenoyl Leucinate.
- 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
lowLess likely to sting, burn, or bother most users, though sensitive skin can still react.
Clogging risk
lowLess likely to feel heavy or contribute to clogged pores for most skin types.
Evidence level
moderateThere is useful support, but formula details and claim strength still matter.
What it is
A semi-synthetic surfactant derived from leucine (an amino acid) and undecenoic acid (a fatty acid from castor oil). It is part of the amino-acid surfactant family, known for their mildness.
How it works
It works by lowering the surface tension between water and oil, allowing impurities to be rinsed away. Its large molecular structure is less penetrating than traditional sulfates, so it cleans effectively without over-stripping the skin’s natural oils.
Pros
Ultra-gentle cleansing
Its large molecular structure means it cleans without penetrating or stripping the skin barrier, making it ideal for sensitive or compromised skin.
Hydrating feel
Unlike many cleansers that leave skin tight, this surfactant helps maintain moisture, so your skin feels soft and comfortable after washing.
Cons and cautions
Lower foam volume
It produces a creamy, low lather rather than big bubbles, which may not satisfy those who associate foam with cleanliness.
Higher cost
Amino-acid surfactants are more expensive to produce, so products containing them often have a higher price tag.
Best for
- People with sensitive, dry, or reactive skin
- Those looking for a sulfate-free, gentle daily cleanser
Use caution if
- Individuals who prefer a very high-foam, bubbly cleansing experience
Usage tips
Safety summary
Methyl Undecenoyl Leucinate is considered very safe for cosmetic use. It has a low irritation and comedogenic risk, and is well-tolerated even by sensitive skin. No significant safety concerns have been reported in regulatory reviews.
Research notes
Research on amino-acid surfactants, including Methyl Undecenoyl Leucinate, shows they are significantly milder than traditional anionic surfactants like sodium lauryl sulfate. Studies indicate they cause less protein denaturation and skin barrier disruption, supporting their use in gentle cleansers.
Common label clues
- Typical concentration
- 1–10% in rinse-off products
- Regulatory status
- Approved for use in cosmetics globally, including by the EU CosIng database and the US FDA as a safe surfactant.
- Common uses
- Facial cleansers, Body washes, Shampoos, Micellar waters
- Environmental note
- Derived from renewable plant sources (castor oil and amino acids) and is biodegradable, making it a more eco-friendly choice compared to some petroleum-based surfactants.
Good to know
- It is often combined with other mild surfactants to adjust foam and cleansing power.
- Look for it in sulfate-free and pH-balanced cleansers for best results.
Common questions
What is Methyl Undecenoyl Leucinate in beauty products?
Methyl Undecenoyl Leucinate is a gentle cleansing ingredient made from leucine, an amino acid found in proteins. It helps remove dirt, oil, and makeup without leaving your skin feeling tight or dry. Unlike harsher soaps, it respects your skin’s natural barrier, making it a favorite for sensitive or dry skin types.
What does Methyl Undecenoyl Leucinate do in a beauty product?
It works by lowering the surface tension between water and oil, allowing impurities to be rinsed away. Its large molecular structure is less penetrating than traditional sulfates, so it cleans effectively without over-stripping the skin’s natural oils.
Is Methyl Undecenoyl Leucinate safe for most people?
Methyl Undecenoyl Leucinate is considered very safe for cosmetic use. It has a low irritation and comedogenic risk, and is well-tolerated even by sensitive skin. No significant safety concerns have been reported in regulatory reviews.
Who should be careful with Methyl Undecenoyl Leucinate?
Individuals who prefer a very high-foam, bubbly cleansing experience
Research sources
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.