The growth of hair follicles takes place in form of cycles. Every cycle is divided into three phases- Anagen, also known as the Growth Phase, Catagen, also called Transitional phase and last, Telogen, better known as the Resting Phase. The initial stage, Anagen, is the most active stage when the hair fiber undergoes growth. This stage lasts for a time span of 2-7 years. In this stage around 85 % of the hair grow out of the hair follicle and become visible on the scalp. At this stage the hair strands are rich in melanin content. The catagen phase is known as the breakdown period which lasts for a time frame of few weeks. In this stage, the hair gets separated from its nutritional content and stops growing. This stage marks the end of growth period and is characterized by a few changes in the follicle.  

The last stage, called the telogen period, lasts between seven weeks to as long as three months. At this time, there is literally no growth of the hair. This means that the predominant percentage of the hair lies in the resting position. The hair sheds begin to take place in this phase and conditions become appropriate for the commencement of the growth period called the Anagen stage.