Abstract: Compositions intended for use for retarding hair loss and for inducing and stimulating its growth, containing 2-aminopyrimidine 3-oxide derivatives, and new compounds derived from 2-aminopyrimidine 3-oxide.Composition for retarding hair loss and for inducing and stimulating its growth, containing at least one compound of formula: ##STR1## where R denotes H, alkyl or a ring of formula: ##STR2## X denotes ##STR3## with: R.sub.1 and R.sub.3 denote H, alkyl, optionally substituted, alkenyl, cycloalkyl, aralkyl or aryl of formula: ##STR4## where R.sub.9 and R.sub.10 denote H, alkyl, hydroxyl, alkoxy or halogen; or form a heterocycle with the nitrogen;R.sub.3 denotes alkyl, alkenyl, cycloalkyl, aralkyl, optionally substituted phenyl;R.sub.4 is identical to R.sub.3 ;Y denotes O or --OSO.sub.3.sup..crclbar. ;R' denotes H or ##STR5## R.sub.5 and R.sub.6 are alkyl; R.sub.7 and R.sub.8 denote H or alkyl;or its physiologically acceptable addition salts with acids.

Abstract: Composition for retarding hair loss and for inducing and stimulating its growth, containing at least one compound of formula: ##STR1## where R denotes H, alkyl or a ring of formula: ##STR2## X denotes ##STR3## --OR.sub.3, --SR.sub.4 with: the remaining variables defined below in the body of the specification.

Abstract: Pharmaceutical or cosmetic composition intended to be used, by topical application, for retarding hair loss and for inducing or stimulating hair growth, containing at least one compound of formula: ##STR1## where: R.sub.1 denotes H or C.sub.1 -C.sub.8 alkyl;R.sub.2 denotes C.sub.1 -C.sub.8 alkyl or NHR.sub.3, where R.sub.3 denotes H or --COOR.sub.4, where R.sub.4 denotes C.sub.1 -C.sub.4 alkyl;X denotes ##STR2## --OR.sub.9 or --SR.sub.10 ; R.sub.5 and R.sub.6 denote H, optionally substituted C.sub.1 -C.sub.12 alkyl, or C.sub.2 -C.sub.12 alkenyl, C.sub.3 -C.sub.10 cycloalkyl, aralkyl or aryl, or form, with N, a saturated or unsaturated heterocycle;R.sub.9 denotes optionally substituted C.sub.1 -C.sub.12 alkyl, or C.sub.2 -C.sub.12 alkenyl, C.sub.3 -C.sub.10 cycloalkyl, C.sub.7 -C.sub.12 aralkyl or phenyl, which may optionally be substituted;R.sub.10 is identical to R.sub.9 ; andY denotes O or OSO.sub.3.sup..crclbar. ;as well as its cosmetically or pharmaceutically acceptable acid addition salts.