Ingredient review
Cis-Non-2-Enal
INCI: CIS-NON-2-ENAL
Cis-Non-2-Enal is a synthetic fragrance ingredient that adds a fresh, green note to products but may cause skin irritation in sensitive individuals.
In plain English
Cis-Non-2-Enal is a man-made chemical used to give skincare and perfume a fresh, green, cucumber-like smell. It belongs to a family of compounds called aldehydes, which are known for their strong scents. In cosmetics, it is used in tiny amounts to create a specific fragrance note. Because it is a fragrance ingredient, it can sometimes cause irritation or allergic reactions, especially on sensitive skin.
Review score
Safety, usefulness, and evidence
Potentially useful with some tradeoffs
The evidence base is useful, but some claims depend heavily on the formula.
Main practical flags: irritation is moderate; clogging risk is low.
- Source
- synthetic
- Evidence
- moderate
- Irritation
- moderate
- Clogging risk
- low
Quick decision guide
Useful, but context matters
Cis-Non-2-Enal can be useful, but watch for some irritation potential.
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 Cis-Non-2-Enal.
- 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
moderateCan bother some users, especially with frequent use, damaged skin, or strong companion ingredients.
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
Cis-Non-2-Enal is a synthetic aldehyde compound with the molecular formula C9H16O. It is a colorless liquid with a strong, fatty-green odor reminiscent of cucumber or fresh grass. It is not naturally derived but is created in a lab for use as a fragrance ingredient.
How it works
In a cosmetic product, Cis-Non-2-Enal functions solely as a fragrance ingredient. It contributes to the overall scent profile by adding a fresh, green top note. It does not provide any skincare benefits like moisturizing or anti-aging; its only role is to make the product smell pleasant.
Pros
Pleasant fresh scent
Adds a clean, green, cucumber-like note that many find appealing in skincare and perfumes.
Low comedogenic risk
Unlikely to clog pores, making it suitable for most skin types when used in low concentrations.
Cons and cautions
Potential irritant
As an aldehyde, it can cause skin irritation or allergic contact dermatitis in sensitive individuals, especially at higher concentrations.
No skincare benefit
Provides only fragrance; it does not moisturize, soothe, or improve skin health in any way.
Best for
- People who enjoy fresh, green-scented products
- Those without fragrance sensitivities
Use caution if
- Individuals with known fragrance allergies or sensitive skin
Usage tips
Safety summary
Cis-Non-2-Enal is generally considered safe for use in cosmetics at low concentrations, but it is a known skin sensitizer and may cause irritation or allergic reactions in some individuals. The International Fragrance Association (IFRA) sets usage limits to minimize risk.
Research notes
Research indicates that Cis-Non-2-Enal can act as a skin sensitizer in patch tests, with moderate evidence of causing allergic contact dermatitis. Studies are limited, but it is recognized as a fragrance allergen that must be declared on labels in the EU.
Common label clues
- Typical concentration
- Very low (typically below 0.1%)
- Regulatory status
- Approved for use as a fragrance ingredient in cosmetics by major regulatory bodies including the EU Cosmetics Regulation and the US FDA, subject to concentration limits and labeling requirements.
- Common uses
- Fragranced skincare, Perfumes, Body care
- Environmental note
- As a synthetic compound, its environmental impact depends on manufacturing processes and disposal; it is not known to be bioaccumulative.
Good to know
- Cis-Non-2-Enal is also found naturally in some foods like cucumbers and is responsible for their characteristic smell.
- It is often used in very low concentrations (below 0.1%) to minimize irritation risk.
Common questions
What is Cis-Non-2-Enal in beauty products?
Cis-Non-2-Enal is a man-made chemical used to give skincare and perfume a fresh, green, cucumber-like smell. It belongs to a family of compounds called aldehydes, which are known for their strong scents. In cosmetics, it is used in tiny amounts to create a specific fragrance note. Because it is a fragrance ingredient, it can sometimes cause irritation or allergic reactions, especially on sensitive skin.
What does Cis-Non-2-Enal do in a beauty product?
In a cosmetic product, Cis-Non-2-Enal functions solely as a fragrance ingredient. It contributes to the overall scent profile by adding a fresh, green top note. It does not provide any skincare benefits like moisturizing or anti-aging; its only role is to make the product smell pleasant.
Is Cis-Non-2-Enal safe for most people?
Cis-Non-2-Enal is generally considered safe for use in cosmetics at low concentrations, but it is a known skin sensitizer and may cause irritation or allergic reactions in some individuals. The International Fragrance Association (IFRA) sets usage limits to minimize risk.
Who should be careful with Cis-Non-2-Enal?
Individuals with known fragrance allergies or sensitive skin
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.