Ingredient review

Nonoxynol-9

INCI: NONOXYNOL-9

Nonoxynol-9 is a harsh synthetic surfactant and spermicide that can irritate skin and disrupt the skin barrier; it is not recommended for routine skincare.

beautyskincaresurfactant

In plain English

Nonoxynol-9 is a man-made chemical that helps break down oils and kill sperm. In skincare, it is sometimes used as a strong cleanser, but it can strip the skin of its natural oils and cause irritation, redness, and dryness. It is much more common in personal lubricants and contraceptive products than in everyday face or body care.

Review score

Safety, usefulness, and evidence

1.5Poor

1.5/ 5

Higher-caution ingredient

The evidence base is relatively strong for its common cosmetic role.

Main practical flags: irritation is high; clogging risk is low.

Source: synthetic
Evidence: strong
Irritation: high
Clogging risk: low

How reviews are scored

Quick decision guide

Read the cautions before using

Nonoxynol-9 can be useful, but watch for high 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 Nonoxynol-9.
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

high

More likely to cause dryness, stinging, peeling, or reactivity if used too aggressively.

Clogging risk

low

Less likely to feel heavy or contribute to clogged pores for most skin types.

Evidence level

strong

There is a stronger practical or research basis for the ingredient role described here.

What it is

Nonoxynol-9 is a synthetic nonionic surfactant and spermicide. It is a clear, viscous liquid that reduces surface tension, allowing it to mix oils and water. It has been used for decades in contraceptive products and some industrial cleaners.

How it works

In a cosmetic product, Nonoxynol-9 acts as a surfactant, helping to remove dirt, oil, and makeup by breaking them into smaller droplets that can be rinsed away. However, it is very effective at disrupting cell membranes, which is why it kills sperm—but this also means it can damage the skin's protective barrier and cause irritation.

Pros

Strong cleansing power

Nonoxynol-9 can effectively break down heavy oils, makeup, and sunscreen, making it useful in some deep-cleansing products.

Spermicidal efficacy

It is a well-studied spermicide used in contraceptive products, though this is not a skincare benefit.

Cons and cautions

High irritation potential

Nonoxynol-9 can cause stinging, redness, and peeling, especially on sensitive skin or with repeated use.

Disrupts skin barrier

It can strip the skin of natural oils and damage the protective barrier, leading to dryness and increased sensitivity.

Not designed for skincare

This ingredient is primarily a spermicide and industrial surfactant; it is rarely found in modern skincare formulations for good reason.

Best for

Only in specific personal lubricant products as directed by a healthcare provider
In very low concentrations in rinse-off cleansers for oily, non-sensitive skin

Use caution if

Anyone with sensitive, dry, or compromised skin
People with eczema, rosacea, or dermatitis
Those using it as a daily facial cleanser

Usage tips

If you encounter Nonoxynol-9 in a cleanser, use it only as a rinse-off product and avoid leaving it on the skin.

Do not use Nonoxynol-9 products on broken, irritated, or sunburned skin.

Consider gentler surfactants like cocamidopropyl betaine or decyl glucoside for daily cleansing.

Safety summary

Nonoxynol-9 is a strong irritant and can damage the skin barrier. It is not recommended for routine skincare use. If present in a product, it should be used sparingly and only in rinse-off formats. The ingredient has been linked to increased risk of irritation and infection with frequent use.

Research notes

Research shows Nonoxynol-9 is an effective spermicide but causes significant irritation to mucous membranes and skin. Studies have found that frequent use can increase the risk of HIV transmission due to barrier disruption. It is not supported for cosmetic use beyond specific, low-concentration applications.

Common label clues

Typical concentration: Up to 5% in spermicidal products; much lower in cleansers
Regulatory status: Approved as a spermicide in many countries, but not typically regulated as a cosmetic ingredient. In the EU, it is restricted in leave-on products due to irritation concerns.
Common uses: Personal lubricants, Spermicidal gels, Rarely in cleansers
Environmental note: Nonoxynol-9 is not readily biodegradable and can be toxic to aquatic life. It is considered an environmental concern when washed down drains.

Good to know

Nonoxynol-9 is not a common ingredient in modern skincare; it is more often found in personal lubricants and contraceptive gels.
The World Health Organization has noted that frequent use of Nonoxynol-9 can increase the risk of vaginal irritation and HIV transmission.

Common questions

What is Nonoxynol-9 in beauty products?

What does Nonoxynol-9 do in a beauty product?

Is Nonoxynol-9 safe for most people?

Who should be careful with Nonoxynol-9?

Anyone with sensitive, dry, or compromised skin People with eczema, rosacea, or dermatitis Those using it as a daily facial cleanser

Research sources

World Health Organization - Nonoxynol-9 and HIVOpen PubMed - Nonoxynol-9 irritation studyOpen Cosmetic Ingredient Review - Safety AssessmentOpen

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.