Salicylic Acid is an aromatic
acid used in cosmetic formulations as a denaturant, hair-conditioning agent, and skin-conditioning agent--miscellaneous in a wide range of cosmetic products at concentrations ranging from 0.0008% to 3%. The
Calcium,
Magnesium, and MEA
salts are preservatives, and
Potassium Salicylate is a cosmetic
biocide and preservative, not currently in use.
Sodium Salicylate is used as a denaturant and preservative (0.09% to 2%). The
TEA salt of
Salicylic Acid is used as an ultraviolet (UV) light absorber (0.0001% to 0.75%). Several
Salicylic Acid esters are used as skin conditioning agents--miscellaneous (Capryloyl, 0.1% to 1%; C12-15 Alkyl, no current use; Isocetyl, 3% to 5%; Isodecyl, no current use; and Tridecyl, no current use). Butyloctyl
Salicylate (0.5% to 5%) and Hexyldodecyl
Salicylate (no current use) are hair-conditioning agents and skin-conditioning agents--miscellaneous. Ethylhexyl
Salicylate (formerly known as Octyl
Salicylate) is used as a fragrance ingredient,
sunscreen agent, and UV light absorber (0.001% to 8%), and
Methyl Salicylate is used as a denaturant and
flavoring agent (0.0001% to 0.6%). Myristyl
Salicylate has no reported function. Isodecyl
Salicylate is used in three formulations, but no concentration of use information was reported.
Salicylates are absorbed percutaneously. Around 10% of applied
salicylates can remain in the skin.
Salicylic Acid is reported to enhance percutaneous penetration of some agents (e.g.,
vitamin A), but not others (e.g.,
hydrocortisone). Little acute toxicity (LD(50) in rats; >2 g/kg) via a dermal exposure route is seen for
Salicylic Acid,
Methyl Salicylate, Tridecyl
Salicylate, and Butyloctyl
Salicylate. Short-term oral, inhalation, and parenteral exposures to
salicylates sufficient to produce high blood concentrations are associated primarily with liver and kidney damage. Subchronic dermal exposures to undiluted
Methyl Salicylate were associated with kidney damage. Chronic oral exposure to
Methyl Salicylate produced bone lesions as a function of the level of exposure in 2-year rat studies; liver damage was seen in dogs exposed to 0.15 g/kg/day in one study; kidney and liver weight increases in another study at the same exposure; but no liver or kidney abnormalities in a study at 0.167 g/kg/day. Applications of Isodecyl, Tridecyl, and Butyloctyl
Salicylate were not irritating to rabbit skin, whereas undiluted Ethylhexyl
Salicylate produced minimal to mild irritation.
Methyl Salicylate at a 1% concentration with a 70%
ethanol vehicle were irritating, whereas a 6% concentration in
polyethylene glycol produced little or no irritation. Isodecyl
Salicylate,
Methyl Salicylate, Ethylhexyl (Octyl)
Salicylate, Tridecyl
Salicylate, and Butyloctyl
Salicylate were not ocular irritants. Although
Salicylic Acid at a concentration of 20% in
acetone was positive in the local lymph node assay, a concentration of 20% in
acetone/
olive oil was not.
Methyl Salicylate was negative at concentrations up to 25% in this assay, independent of vehicle. Maximization tests of
Methyl Salicylate, Ethylhexyl
Salicylate, and Butyloctyl
Salicylate produced no sensitization in guinea pigs. Neither
Salicylic Acid nor Tridecyl
Salicylate were
photosensitizers.
Salicylic Acid, produced when
aspirin is rapidly hydrolyzed after absorption from the gut, was reported to be the causative agent in
aspirin teratogenesis in animals. Dermal exposures to
Methyl Salicylate, oral exposures to
Salicylic Acid,
Sodium Salicylate, and
Methyl Salicylate, and parenteral exposures to
Salicylic Acid,
Sodium Salicylate, and
Methyl Salicylate are all associated with reproductive and developmental toxicity as a function of blood levels reached as a result of exposure. An exposure assessment of a representative cosmetic product used on a daily basis estimated that the exposure from the cosmetic product would be only 20% of the level seen with ingestion of a "baby"
aspirin (81 mg) on a daily basis. Studies of the genotoxic potential of
Salicylic Acid,
Sodium Salicylate, Isodecyl
Salicylate,
Methyl Salicylate, cosmetic product would be only 20% of the level seen with ingestion of a "baby"
aspirin (81 mg) on a daily basis. Studies of the genotoxic potential of
Salicylic Acid,
Sodium Salicylate, Isodecyl
Salicylate,
Methyl Salicylate, Ethylhexyl (Octyl)
Salicylate, Tridecyl
Salicylate, and Butyloctyl
Salicylate were generally negative.
Methyl Salicylate, in a mouse skin-painting study, did not induce
neoplasms. Likewise,
Methyl Salicylate was negative in a mouse pulmonary
tumor system. In clinical tests,
Salicylic Acid (2%) produced minimal cumulative irritation and slight or no irritation(1.5%);
TEA-
Salicylate (8%) produced no irritation;
Methyl Salicylate (>12%) produced
pain and
erythema, a 1%
aerosol produced
erythema, but an 8%
solution was not irritating; Ethylhexyl
Salicylate (4%) and undiluted Tridecyl
Salicylate produced no irritation. In atopic patients,
Methyl Salicylate caused irritation as a function of concentration (no irritation at concentrations of 15% or less). In normal skin,
Salicylic Acid,
Methyl Salicylate, and Ethylhexyl (Octyl)
Salicylate are not sensitizers.
Salicylic Acid is not a
photosensitizer, nor is it phototoxic.
Salicylic Acid and Ethylhexyl
Salicylate are low-level photoprotective agents.
Salicylic Acid is well-documented to have keratolytic action on normal human skin. Because of the possible use of these ingredients as exfoliating agents, a concern exists that repeated use may effectively increase exposure of the dermis and epidermis to UV radiation. It was concluded that the prudent course of action would be to advise the
cosmetics industry that there is a risk of increased UV radiation damage with the use of any exfoliant, including
Salicylic Acid and the listed
salicylates, and that steps need to be taken to formulate cosmetic products with these ingredients as exfoliating agents so as not to increase sun sensitivity, or when increased sun sensitivity would be expected, to include directions for the daily use of sun protection. The available data were not sufficient to establish a limit on concentration of these ingredients, or to identify the minimum pH of formulations containing these ingredients, such that no skin irritation would occur, but it was recognized that it is possible to formulate cosmetic products in a way such that significant irritation would not be likely, and it was concluded that the
cosmetics industry should formulate products containing these ingredients so as to be nonirritating. Although simultaneous use of several products containing
Salicylic Acid could produce exposures greater than would be seen with use of baby
aspirin (an exposure generally considered to not present a reproductive or developmental toxicity risk), it was not considered likely that consumers would simultaneously use multiple cosmetic products containing
Salicylic Acid. Based on the available information, the Cosmetic Ingredient Review Expert Panel reached the conclusion that these ingredients are safe as used when formulated to avoid skin irritation and when formulated to avoid increasing the skin's sun sensitivity, or, when increased sun sensitivity would be expected, directions for use include the daily use of sun protection.