Ingredient review
Laneth-40
INCI: LANETH-40
Laneth-40 is a gentle, water-friendly emulsifier derived from lanolin that helps blend oils and water in creams and cleansers, but may not suit those with lanolin allergies.
In plain English
Laneth-40 is a modified version of lanolin (a natural oil from sheep's wool) that has been treated with polyethylene glycol (PEG) to make it dissolve in water. In skincare, it acts as a helper ingredient that allows oil and water to mix smoothly, creating stable creams and lotions. It also leaves a soft, conditioned feel on the skin without the heavy, greasy texture of plain lanolin.
Review score
Safety, usefulness, and evidence
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
Quick decision guide
Useful, but context matters
Laneth-40 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 Laneth-40.
- 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
Laneth-40 is a semi-synthetic ingredient made by reacting lanolin with ethylene oxide (PEG). It belongs to the family of ethoxylated lanolins, which are designed to be water-soluble while retaining the moisturizing properties of natural lanolin. It appears as a waxy solid or liquid and is commonly used as an emulsifier and surfactant.
How it works
In a cosmetic formula, Laneth-40 sits at the boundary between oil and water droplets, reducing surface tension so they can blend into a stable emulsion. This prevents creams and lotions from separating. It also helps other ingredients spread evenly on the skin and leaves a light, non-greasy film that softens the skin's surface.
Pros
Gentle emulsifier
Laneth-40 helps oil and water mix smoothly, giving your creams and lotions a stable, pleasant texture without separating.
Light skin feel
Unlike plain lanolin, Laneth-40 is water-soluble and leaves a soft, non-greasy finish, making it suitable for lighter formulations.
Cons and cautions
Lanolin allergy risk
Because it is derived from lanolin, people with wool or lanolin allergies may experience irritation or allergic reactions.
PEG-related contamination
The manufacturing process can create trace amounts of 1,4-dioxane, a potential carcinogen, though reputable brands purify their ingredients to safe levels.
Best for
- People who enjoy creamy, stable moisturizers and cleansers
- Those with normal to dry skin looking for light conditioning
Use caution if
- Individuals with known lanolin allergy or wool sensitivity
Usage tips
Safety summary
Laneth-40 is generally safe for most people when used in cosmetics at typical concentrations. The main concern is potential allergy in individuals sensitive to lanolin. Trace 1,4-dioxane is a manufacturing impurity that is minimized by quality control. Regulatory bodies like the CIR have reviewed it and found it safe for its intended use.
Research notes
Research on Laneth-40 is limited, but it is part of the broader family of ethoxylated lanolins, which have been evaluated by the Cosmetic Ingredient Review (CIR) panel. Studies indicate low irritation and sensitization potential in most individuals, though patch testing is recommended for those with known lanolin allergies.
Common label clues
- Typical concentration
- 1% to 10%
- Regulatory status
- Approved for use in cosmetics in the US, EU, and many other regions. The Cosmetic Ingredient Review (CIR) panel has deemed it safe as used in rinse-off and leave-on products.
- Common uses
- Cleansers, Moisturizers, Makeup removers, Hair conditioners
- Environmental note
- Derived from lanolin, a byproduct of wool production, which is a renewable resource. The ethoxylation process involves ethylene oxide, which requires careful industrial handling.
Good to know
- Laneth-40 is often used in combination with other lanolin derivatives like Laneth-10 or Laneth-60
- It is considered safe by the Cosmetic Ingredient Review (CIR) panel at typical use levels
Common questions
What is Laneth-40 in beauty products?
Laneth-40 is a modified version of lanolin (a natural oil from sheep's wool) that has been treated with polyethylene glycol (PEG) to make it dissolve in water. In skincare, it acts as a helper ingredient that allows oil and water to mix smoothly, creating stable creams and lotions. It also leaves a soft, conditioned feel on the skin without the heavy, greasy texture of plain lanolin.
What does Laneth-40 do in a beauty product?
In a cosmetic formula, Laneth-40 sits at the boundary between oil and water droplets, reducing surface tension so they can blend into a stable emulsion. This prevents creams and lotions from separating. It also helps other ingredients spread evenly on the skin and leaves a light, non-greasy film that softens the skin's surface.
Is Laneth-40 safe for most people?
Laneth-40 is generally safe for most people when used in cosmetics at typical concentrations. The main concern is potential allergy in individuals sensitive to lanolin. Trace 1,4-dioxane is a manufacturing impurity that is minimized by quality control. Regulatory bodies like the CIR have reviewed it and found it safe for its intended use.
Who should be careful with Laneth-40?
Individuals with known lanolin allergy or wool sensitivity
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.