During hair growth the follicles follow a cyclical and asynchronous growth phase. This cycle is made up of three distinct phases : anagen, catagen and telogen. Each hair passes through the phases inde- pendently from the neighboring hairs. Hair loss problems, which are generally called alopecia, often are caused by an During hair growth the follicles follow a cyclical and asynchronous growth phase. This cycle is made up of three distinct phases : anagen, catagen and telogen. Each hair passes through the phases inde- pendently from the neighboring hairs. Hair loss problems, which are generally called alopecia, often are caused by an During hair growth the follicles follow a cyclical and asynchronous growth phase. This cycle is made up of three distinct phases : anagen, catagen and telogen. Each hair passes through the phases inde- pendently from the neighboring hairs. Hair loss problems, which are generally called alopecia, often are caused by an