Phytantriol is an alcohol used in around 100 cosmetic products at concentrations ranging from 0.0002% to 1.0%, although uses at concentrations up to 3% are under development. Phytanriol is supplied at 95.2% and 96.0% purity. Impurities include water, sulphated ash, heavy metals, and a diastereomer of Phytantriol, 3,7,11,15-tetramethyl-1,2,3,4-tetrahydroxyhexadecane. Dermal penetration is low; skin permeability was calculated as log Kp = - 1.734. Oral LD50 values in mice and rats were reported to be > 5000 mg/kg. Ocular application of 100% Phytantriol did cause severe corneal damage in some animals, at 23% in diethyl phthalate only slight corneal opacity was seen, and at 10% transient opacity was seen, which resolved by 48 h. Phytantriol at 100% was a severe skin irritant in animal tests. Phytantriol at 3% and 10% in diethyl phthalate produced only slight erythema, which cleared by 48 h. Phytantriol, in the Longhorn egg chorioallantoic membrane assay, was found to have almost no irritation potential when tested at 3% concentration in corn oil. Phytantriol at 25% did produce sensitization in a maximization test, but concentrations of 1% and lower did not cause a sensitization response. Phytantriol is neither phototoxic nor photoallergenic. Phytantriol did not induce aberrations in cultured human lymphocytes, when tested within cytotoxicity limits, nor was it mutagenic in Ames tests, with or without metabolic activation. None of 101 human volunteers reacted initially or to challenge patches of 3% Phytantriol in corn oil. In another investigation of 227 volunteers induced and challenged with 3% Phytantriol in 70:30 ethyl alcohol/water, one person had a mild reaction to the first induction patch; this was the only positive reaction during the induction and challenge phases for all of the volunteers. Phytantriol had no adverse effects in any of 206 volunteer subjects in a repeat insult patch test at 5%. Although data were not available with which to assess reproductive and developmental toxicity and carcinogenic potential, there were no structural alerts suggesting that these end points should be of concern. Dermal penetration is low, and Phytantriol is not genotoxic. Although products containing this ingredient may be aerosolized, typical particle sizes for cosmetic aerosol products are larger than are respirable. Although this ingredient can be irritating and produce sensitization reactions at high concentrations, such effects are absent at lower concentrations. The Panel concluded that cosmetic products could be formulated at concentrations as high as 3% without significant irritation or sensitization.