What Is It?

Nonoxynol-1, -2, -3, -4, -5, -6, -7, -8, 9, -10, -12, -14, -15, -30, -40 and -50 can be liquids, paste-like liquids, or waxes. In cosmetics and personal care products, Nonoxynols are used in hair and skin care products, bath and shaving products, and personal cleanliness products. Nonoxynols-1, -2, -3, -4, -5, -6, -7, and -8 (lower molecular weight Nonoxynols) are used principally in hair dyes and colors.

Why Is It Used?

The Nonoxynols help to form emulsions by reducing the surface tension of the substances to be emulsified. The higher molecular weight Nonoxynols also help other ingredients to dissolve in a solvent in which they would not normally dissolve and they are used to increase foaming capacity or to stabilize foams.

Scientific Facts

The Nonoxynols range from Nonoxynol-1 to Nonoxynol-100. The numerical value represents the average number of moles of ethylene oxide added to produce the specific Nonoxynol ingredient. For example, Nonoxynol-9 is made by reacting nonylphenol with 5-18 moles of ethylene oxide, resulting in an average value of 9.

Safety Information

The Food and Drug Administration (FDA) has reviewed the safety of Nonoxynol-1, -5 and -6 and permits the use of these substances as indirect food additives. The safety of the Nonoxynols has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated scientific data and based concluded that Nonoxynols-9, -10, -12, -14, -15, -30, -40 and -50 are safe as cosmetic ingredients in the present practices of concentration and use.

In 1999, the CIR Expert Panel considered available new data on the lower molecular weight Nonoxynols and concluded that Nonoxynol-1, -2, -3, -4, -5, -6, -7, and -8 are safe as used in rinse-off products and safe at concentrations of 5% or less in leave-on products.

CIR Safety Review: The CIR Expert Panel assessed the safety of Nonoxynol-2, -4, -8, -9, -10, -12, -14, -15, -30, -40, and -50. Subsequent to that report, new data were available on the lower molecular weight Nonoxynols (-1 to -8) and the CIR Expert Panel concluded that all of the Nonoxynol ingredients are safe for use in rinse-off products, and safe at concentrations of 5% or less in leave-on products. The CIR Expert Panel reviewed data on the low molecular weight Nonoxynols that showed no significant skin penetration in which Nonoxynols-2, -4, and -9 were applied in conditions simulating leave-on or rinse-off applications. Under both conditions, the total skin penetration of Nonoxynol-2, -4, and -9 was less than 1% over a 48-hour period. Results of acute oral toxicity studies indicated that the lower molecular weight Nonoxynols were at most slightly toxic.

Nonoxynol-5 and -6 produce severe ocular irritation. They also produce skin irritation, but are not sensitizers. Due to the severity of ocular irritation reactions, avoiding the use of products containing low molecular weight Nonoxynols in the area surrounding the eyes was discussed. The no-adverse-effect level in reproductive and developmental toxicity tests in which Nonoxynol-9 was delivered orally or intravaginally was higher than any possible exposure from cosmetics and personal care products.

There is no evidence for genotoxicity or carcinogenicity. Clinical studies using Nonoxynol-9 showed irritation of the vaginal mucosa, along with increased epithelial disruption. A 2% solution of Nonoxynol-8.3 and -9 was sensitizing in dermatitis patients. A repeat insult patch test in normal volunteers using Nonoxynol-2 at a concentration of 5% showed no evidence of allergic contact dermatitis, but there were reactions at 10%.

Therefore, the CIR Expert Panel determined that concentrations of Nonoxynol-2 and -4 and other lower-molecular-weight Nonoxynols (not greater than Nonoxynol-8) should be limited to 5% or less in leave-on products. After reviewing data on the higher molecular weight Nonoxynols (-9 to -50), the CIR Expert Panel noted that differences in toxic effects among these higher molecular weight Nonoxynols are quantitative and most likely related to the rate of absorption as influenced by the ethoxy groups. There was no evidence of qualitative differences in toxicity between these Nonoxynols; therefore, the CIR Expert Panel used the composite data to evaluate the safety of this group of ingredients. Skin irritation tests indicated that higher molecular weight Nonoxynols are nonirritating to moderately irritating.

Nonoxynol compounds with short ethoxylated chains are generally severe ocular irritants, whereas long-chained Nonoxynols are only slightly irritating to the eye. A 50% solution of Nonoxynol-15 and/or Nonoxynol-50 produced no irritation or sensitization when tested on 168 subjects, nor was there evidence of phototoxicity when tested on a subset of this population. Ethylene oxide residues, although present in small amounts in several preparations, were not considered sufficient to present a carcinogenesis risk. Unreacted nonylphenol may be present in low molecular weight Nonoxynols, but are generally less than 500 ppm. The CIR Expert Panel noted the need for product formulators to exercise care so that any nonylphenol in finished products is not found in toxic amounts.

Link to FDA Code of Federal Regulations for p-Nonylphenyls.

Nonoxynols are banned for use cosmetics and personal care products marketed in the European Union.

EU Cosmetic Regulation

More Scientific Information

Nonoxynols are chemically stable ethoxylated alkylphenols. In cosmetics and personal care products, they are used as surfactants (emulsifing agents). The higher molecular weight Nonoxynols are also used as surfactants (solubilizing agents and foam boosters) and wetting agents.


Find out more about the regulation of Food Additives by the Food and Drug Administration