Ingredient review

Indole

INCI: INDOLE

Indole is a fragrant compound found in flowers and coal tar, used in tiny amounts for scent; it can be irritating at higher levels and is not a primary active ingredient.

beautyskincarefragrance

In plain English

Indole is a chemical that naturally occurs in flowers like jasmine and orange blossoms, and also in coal tar. In skincare and perfumes, it's used in very small amounts to add a floral or animal-like scent. Because it's strong and can irritate skin, it's usually found at low levels. It's not a moisturizer or anti-aging ingredient—it's mainly there for fragrance.

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: natural
Evidence: moderate
Irritation: moderate
Clogging risk: low

How reviews are scored

Quick decision guide

Useful, but context matters

Indole 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 Indole.
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

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

Indole is an organic aromatic heterocyclic compound. It occurs naturally in many plants (especially white flowers) and is also produced synthetically for use in fragrances and some skincare products. In cosmetics, it functions primarily as a fragrance ingredient and, at low levels, may have mild skin-conditioning effects.

How it works

In a cosmetic product, indole contributes to the overall scent profile, often adding a floral, slightly animalic note. At very low concentrations, it may also help condition the skin by interacting with skin proteins, but this effect is minimal compared to dedicated conditioning agents. Its primary role is olfactory.

Pros

Adds complex floral scent

Indole provides a rich, natural floral note that enhances the fragrance experience in perfumes and scented skincare products.

Low concentration use

Because it's potent, indole is used in very small amounts, reducing the likelihood of irritation for most people.

Cons and cautions

Potential skin irritant

At higher concentrations, indole can cause redness, itching, or stinging, especially for those with sensitive skin.

Strong, divisive odor

Some people find indole's scent unpleasant or overpowering, especially if they are sensitive to animalic notes.

Best for

People who enjoy floral or complex fragrances in their skincare
Those using products where indole is listed near the end of the ingredient list (low concentration)

Use caution if

Individuals with sensitive or reactive skin should avoid products with indole high on the ingredient list

Usage tips

Check the ingredient list: if indole appears near the end, it's at a very low concentration and less likely to cause issues.

Patch test any product containing indole if you have sensitive skin, especially if it's a leave-on product like a serum or moisturizer.

Safety summary

Indole is generally safe in the very low concentrations used in cosmetics. However, it can cause skin irritation or allergic reactions in sensitive individuals, especially at higher levels. Regulatory bodies set usage limits to protect consumers.

Research notes

Research on indole in cosmetics is limited. Studies focus on its role as a fragrance allergen and its potential for skin sensitization. It is not a well-studied active ingredient for skin benefits beyond scent.

Common label clues

Typical concentration: Typically used at very low concentrations (under 0.1%) due to its strong odor and potential for irritation.
Regulatory status: Indole is approved for use as a fragrance ingredient in cosmetics by the International Fragrance Association (IFRA) and is subject to concentration limits to minimize irritation risk. It is not banned by major regulators like the FDA or EU CosIng, but must be listed on the ingredient label.
Common uses: Fragrances, Perfumes, Scented Skincare
Environmental note: Indole is biodegradable and naturally occurring, but synthetic production may involve petrochemicals. Its environmental impact is considered low due to the tiny amounts used.

Good to know

Indole is also found in human feces and coal tar, which is why its scent can be off-putting at high levels.
In perfumery, indole is prized for adding depth and naturalness to floral scents like jasmine and tuberose.

Common questions

What is Indole in beauty products?

What does Indole do in a beauty product?

Is Indole safe for most people?

Who should be careful with Indole?

Individuals with sensitive or reactive skin should avoid products with indole high on the ingredient list

Research sources

IFRA Standards on IndoleOpen CosIng - IndoleOpen PubMed - Indole and Skin SensitizationOpen

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.