SOLUBLE SUBSTANCE AND MIXTURE OF SOLUBLE SUBSTANCES AND COMPOSITION CONTAINING AT LEAST ONE SOLUBLE SUBSTANCE FOR USE IN PREVENTION OR TREATMENT OF COSMETIC OR PATHOLOGICALLY EXPLOSED HEADS
R1=H or alkyl; R2=H, COOH, COO-alkyl or CO—NH—R5; R3 and R4 each independently H or OH; R5=H, alkyl, an amino acid residue, dipeptide residue or tripeptide residue and n=1, 2 or 3 and alkyl corresponds to an alkyl group having C1-C4 carbon atoms.