A compound selected from compounds having the following formula: ** Formula ** where a, b and c respectively indicate, independently of each other, a single bond or a double bond, with the proviso that at least one of a, b and c represents a double bond, and with the proviso that if a is a single bond and b is a double bond R2 it is not H； R1 is hydrogen or C1 to C6 alkyl； R2 is OR5, where R5 is hydrogen or C1 to C6 straight or branched alkyl； R3 is, if c is a single bond, hydrogen or C1 to C6 alkyl, or if c is a double bond, CHR5, where R5 is the same as defined above； R4 is hydrogen, C1 to C6 alkyl, phenyl unsubstituted or substituted by C1 to C6 alkyl, or a COR6 acyl group (R6 being hydrogen, straight or branched C1 to C6 alkyl, phenyl or benzoyl respectively unsubstituted or substituted by alkyl C1 to C6)； and salts thereof； for use in the prophylaxis and / or treatment selected from: a therapeutic treatment of the skin in which it is intended to fortify, stabilize and / or increase the collagen for purposes other than cellulite； such as disorders that result from exposure of the skin to the sun； a therapeutic treatment that stimulates the synthesis of collagen via anabolic effects which implies an application in the ligaments, fascia, tendons, cartilage, bones, dentin and vascular walls of the arteries, veins or urinary tract； myocardial infarction and cerebral infarction； arteriosclerosis； urinary incontinence； osteoporosis； and mastalgia； and for use in women who are undergoing hormone replacement therapy.Un compuesto seleccionado de compuestos que tienen la siguiente fórmula:**Fórmula** donde a, b y c respectivamente indican, independientemente entre sí, un enlace simple o un enlace doble, con la condición de que por lo menos uno de a, b y c represente un enlace doble, y con la condición de que si a es un enlace simple y b es un enlace doble R2 no sea H； R1 es hidrógeno o alquilo C1 a C6； R2 es OR5, donde R5 es hidrógeno o alquilo C1 a C6 de cadena recta o r
