Ingredient review

Trimethyl Cyclohexene Methanethiol

INCI: TRIMETHYL-3-CYCLOHEXENE-1-METHANETHIOL

A synthetic fragrance ingredient that adds a unique scent but may cause skin irritation in sensitive individuals.

beautyskincarefragrance

In plain English

This is a man-made chemical used to give products a specific smell, often described as grapefruit-like or sulfurous. It belongs to a group called thiols, which are known for their strong odors even at tiny amounts. In skincare, it's added in very low concentrations to create a pleasant fragrance, but like many fragrance ingredients, it can be irritating for some people.

Review score

Safety, usefulness, and evidence

3.5Good
3.5/ 5

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
How reviews are scored

Quick decision guide

Useful, but context matters

Trimethyl Cyclohexene Methanethiol 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.

  1. Step 1Start with the score, then check the irritation and clogging risk before judging Trimethyl Cyclohexene Methanethiol.
  2. Step 2Use the "Best for" and "Use caution if" sections to match the ingredient to your skin, not just to a marketing claim.
  3. 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

moderate

Can bother some users, especially with frequent use, damaged skin, or strong companion ingredients.

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

Trimethyl-3-cyclohexene-1-methanethiol is a synthetic organic compound from the thiol family. Thiols contain a sulfur atom, which gives them potent, often pungent aromas. This specific molecule is used in the fragrance industry to impart a fresh, citrusy, or grapefruit-like note.

How it works

In a cosmetic product, this ingredient functions solely as a fragrance component. It interacts with olfactory receptors in the nose to produce a scent perception. It does not provide any skincare benefit like moisturizing, exfoliating, or protecting the skin. Its role is purely sensory, enhancing the user experience through smell.

Pros

Unique Scent Profile

Provides a distinctive grapefruit-like or fresh aroma that can make a product more enjoyable to use.

Low Use Concentration

Effective at very low levels, meaning it's present in tiny amounts in the final product, which can reduce overall exposure.

Cons and cautions

Potential Irritant

As a fragrance ingredient, it can cause skin irritation, redness, or stinging, particularly for those with sensitive skin.

No Skincare Benefit

This ingredient adds only scent; it does not hydrate, repair, or improve skin health in any way.

Best for

  • Individuals who enjoy scented skincare and have no history of fragrance allergies
  • People using products where fragrance is a key part of the experience

Use caution if

  • Those with sensitive, reactive, or eczema-prone skin
  • Anyone with a known allergy or sensitivity to fragrance ingredients

Usage tips

If you have sensitive skin, look for products labeled 'fragrance-free' to avoid this and other fragrance ingredients.
Patch test any new scented product on a small area of skin before applying it to your face or body.
Use scented products on areas with thicker skin, like the body, rather than the delicate facial skin if you are prone to irritation.

Safety summary

Trimethyl-3-cyclohexene-1-methanethiol is considered safe for use in cosmetics at low concentrations by fragrance safety panels. However, like many fragrance ingredients, it carries a risk of skin irritation and allergic contact dermatitis in sensitive individuals. It is not known to be carcinogenic or toxic in the small amounts used.

Research notes

Research on this specific compound is limited, but it is evaluated as part of broader fragrance safety assessments. Studies on similar thiols indicate potential for skin sensitization. The ingredient is generally recognized as safe when used within IFRA guidelines, but individual sensitivity varies.

Common label clues

Typical concentration
Very low, typically less than 0.1% in finished products
Regulatory status
Approved for use as a fragrance ingredient in cosmetics and personal care products, subject to concentration limits and safety guidelines set by organizations like IFRA and the FDA (as part of fragrance regulation).
Common uses
Fragranced skincare, Perfumes, Body lotions, Cleansers
Environmental note
As a synthetic compound, its environmental impact depends on manufacturing processes and disposal. It is not known to be bioaccumulative, but limited data is available on its long-term ecological effects.

Good to know

  • Thiols are known for their strong odors; this one is used to mimic the scent of grapefruit.
  • Fragrance ingredients are often listed simply as 'parfum' or 'fragrance' on labels, so you may not see this specific name.
  • Regulatory bodies like the International Fragrance Association (IFRA) set safety standards for the use of this ingredient in cosmetics.

Common questions

What is Trimethyl Cyclohexene Methanethiol in beauty products?

This is a man-made chemical used to give products a specific smell, often described as grapefruit-like or sulfurous. It belongs to a group called thiols, which are known for their strong odors even at tiny amounts. In skincare, it's added in very low concentrations to create a pleasant fragrance, but like many fragrance ingredients, it can be irritating for some people.

What does Trimethyl Cyclohexene Methanethiol do in a beauty product?

In a cosmetic product, this ingredient functions solely as a fragrance component. It interacts with olfactory receptors in the nose to produce a scent perception. It does not provide any skincare benefit like moisturizing, exfoliating, or protecting the skin. Its role is purely sensory, enhancing the user experience through smell.

Is Trimethyl Cyclohexene Methanethiol safe for most people?

Trimethyl-3-cyclohexene-1-methanethiol is considered safe for use in cosmetics at low concentrations by fragrance safety panels. However, like many fragrance ingredients, it carries a risk of skin irritation and allergic contact dermatitis in sensitive individuals. It is not known to be carcinogenic or toxic in the small amounts used.

Who should be careful with Trimethyl Cyclohexene Methanethiol?

Those with sensitive, reactive, or eczema-prone skin Anyone with a known allergy or sensitivity to fragrance ingredients

Research sources

International Fragrance Association (IFRA) StandardsOpenPubMed - Thiols and Skin SensitizationOpenCosIng - EU Cosmetic Ingredient DatabaseOpen

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.