USE OF 13-HYDROXY-9,11-OCTADECADIENOIC ACID FOR TANNING HUMAN SKIN

1 . A method for tanning human skin and/or for maintaining an existing skin tan, the method comprising applying 13-hydroxy-9,11-octadecadienoic acid to human skin.

2 . (canceled)

3 . The method of claim 1 , wherein said 13-hydroxy-9,11-octadecadienoic acid is a component in a cosmetic formulation.

4 . The method of claim 1 , wherein said tanning is achieved without exposing the skin to UV radiation.

5 . The method of claim 1 , wherein said human skin is exposed to UV light after 13-hydroxy-9,11-octadecadienoic acid and/or a formulation comprising 13-hydroxy-9,11-octadecadienoic acid is applied to the skin.

6 . The method of claim 1 , wherein uneven coloration induced by dihydroxyacetone and/or erythrulose is corrected by applying said 13-hydroxy-9,11-octadecadienoic acid and/or a formulation comprising 13-hydroxy-9,11-octadecadienoic acid to skin having an uneven coloration as a result of treatment with dihydroxyacetone and/or erythrulose.

7 . A method for coloring human hair, the method comprising applying 13-hydroxy-9,11-octadecadienoic acid to the scalp.

8 . The method according to claim 1 , wherein said 13-hydroxy-9,11-octadecadienoic acid is applied repeatedly to the skin.

9 . The method of claim 1 , wherein said method also treats skin having polymorphous photodermatosis, and/or prevents the skin from polymorphous photodermatosis.

10 . The method of claim 1 , wherein said 13-Hydroxy-9,11-octadecadienoic acid has a 9-Z 11-E isomeric configuration.

11 . The method of claim 1 , wherein said 13-Hydroxy-9,11-octadecadienoic acid has an S stereoconfiguration at the C13 carbon atom.

12 . The method of claim 1 , wherein said 13-Hydroxy-9,11-octadecadienoic acid has a 9-Z 11-E isomeric configuration and an S stereoconfiguration at the C13 carbon atom.

13 . The method of claim 3 , wherein said cosmetic formulation comprises said 13-Hydroxy-9,11-octadecadienoic acid in an amount of 0.00001 to 1 percent by mass based on the total mass of the cosmetic formulation.

14 . The method of claim 3 , wherein said cosmetic formulation comprises said 13-Hydroxy-9,11-octadecadienoic acid in an amount of 0.00005 to 0.5 percent by mass based on the total mass of the cosmetic formulation.

15 . The method of claim 3 , wherein said cosmetic formulation comprises said 13-Hydroxy-9,11-octadecadienoic acid in an amount of 0.0001 to 0.1 percent by mass based on the total mass of the cosmetic formulation.

16 . The method of claim 3 , wherein said cosmetic formulation is a sunscreen formulation.

17 . The method of claim 16 , wherein said sunscreen formulation comprises at least one UV radiation-absorbing substance.

18 . The method of claim 17 , wherein said at least one UV radiation-absorbing substance is selected from cinnamic esters, ester of salicylic acid, benzophenone, and finely dispersed metal oxides.

19 . The method of claim 7 , further comprising restoring original hair color in hair that has become gray.