A hair treatment agents having a pH of between 3.5 and 5.5 that can be obtained by mixing (i) 0.00001 to 20 wt.% — based on the total weight of the hair treatment agent — of at least one oligopeptide that comprises at least one Glu-Glu-Glu amino acid sequence where the amino group may be in free or protonated form and the carboxyl groups may be in free or deprotonated form, and (ii) 0.00001 to 5.0 wt.% — based on the total weight of the hair treatment agent — of magnesium citrate in a hydrous carrier. More preferably, the oligopeptide contains the Tyr-Glu-Glu-Glu-Ile (YEEEI) subunit. Most preferably, the oligopeptide contains the Tyr-Glu-Glu-Glu-Ile-Arg-Val-Leu (YEEEIRVL) sequence. The hair treatment agent may also comprise 0.5 to 70 wt.% (most preferably, 5 to 25 wt.%) surfactant(s) and 0.05 to 7.5 wt.% (most preferably 0.25 to 2.5 wt.%) cationic polymer(s).
