Method for straightening the hair using a composition containing glyoxylic acid and/or a derivative thereof

The method as claimed in any one of the preceding claims, wherein the amount of glyoxylic acid and/or of derivatives thereof is at least 3% by weight of the total weight of the composition, preferably ranging from 3% to 10% by weight of the total weight of the composition.

The method as claimed in any one of the preceding claims, wherein the composition containing glyoxylic acid and/or a derivative thereof additionally comprises a nonionic cellulose-based polymer.

The method as claimed in any one of the preceding claims, wherein, in step (ii), the leave-on time ranges from 10 to 60 min, preferably from 20 to 35 min.

The method as claimed in any one of the preceding claims, wherein, in step (iii), at least one hair treatment compound chosen from fatty alcohols and/or cationic polymers and/or cationic surfactants is applied.

The method as claimed in any one of the preceding claims, wherein the hair treatment compound(s) chosen from fatty alcohols and/or cationic conditioning agents is (are) present for each of the categories in an amount ranging from 0.01% to 10% by weight, even better still from 0.1% to 8% by weight and even more preferentially from 0.5% to 5% by weight relative to the total weight of the composition containing it or them.

The method as claimed in any one of the preceding claims, wherein the composition (iii) containing the hair treatment compound(s) chosen from fatty alcohols and/or cationic conditioning agents, after a leave-on time of generally less than 20 min, preferably ranging from 1 to 15 min, is rinsed off before the heat application step is carried out.

The method as claimed in any one of the preceding claims, wherein the heat application step comprises a single step which consists in straightening the hair with a straightening iron at a temperature of at least 150° C., preferably from 200 to 250° C.

The method as claimed in any one of the preceding claims, wherein the heat application step comprises a first step which consists in straightening the hair by means of a brush and a hairdryer (step known as blow drying) and a second step which consists in straightening the hair with a straightening iron at a temperature of at least 150° C., preferably from 200 to 250° C.

The method as claimed in any one of the preceding claims, comprising, before the application of the composition of step (i), a pretreatment which comprises the application of a composition comprising at least one siliceous compound comprising at least one silicon atom, preferably an alkoxysilane optionally organically modified with one or more amino groups, or a silicone, preferably a polydimethylsiloxane optionally substituted with one or more amino groups.

The method as claimed in the preceding claim, wherein the pretreatment composition comprising at least one siliceous compound is not rinsed off.