Cosmetic composition comprising 2,4-diaminopyrimidine 3-n-oxide, piroctone olamine, niacinamide, and at least 1% by weight of particular hydroxylated compound

A cosmetic composition comprising:

• i) 2,4-diaminopyrimidine 3-N-oxide, an organic or mineral acid salt thereof or a hydrate thereof,
• ii) piroctone olamine,
• iii) niacinamide, and
• iv) at least one hydroxylated compound with a melting point below 25° C. at atmospheric pressure (1.013×105 Pa) and a boiling point of greater than or equal to 170° C., wherein the total amount of the at least one hydroxylated compound is at least 1% by weight, relative to the total weight of the composition.

A method for treating human keratin materials, comprising applying to said keratin materials a composition comprising:

• i) 2,4-diaminopyrimidine 3-N-oxide, an organic or mineral acid salt thereof or a hydrate thereof,
• ii) piroctone olamine,
• iii) niacinamide, and
• iv) at least one hydroxylated compound with a melting point below 25° C. at atmospheric pressure (1.013×105 Pa) and a boiling point of greater than or equal to 170° C., wherein the total amount of the at least one hydroxylated compound is at least 1% by weight, relative to the total weight of the composition.