Understanding the Hair Growth Cycle | Segal Solutions

The hair growth cycle is a continuous, natural process in which hair follicles grow in repeated phases. Each follicle functions independently and moves through the cycle without being synchronized with its neighboring follicles. This cycle consists of three main stages: the anagen phase of hair, the catagen phase, and the telogen phase.

Anagen Phase – Growth Phase

The anagen phase of hair is the active growth period. Approximately 85% of all hair strands are in this stage at any given time. This phase can last anywhere from two to six years, depending on genetics and overall health. Hair grows at a rate of about 12–15 cm per year, and typically, a single strand will not grow longer than one meter. This phase is critical in the hair growth cycle, as the longer the hair remains in anagen, the longer it can grow.

Catagen Phase – Transitional Phase

Following the anagen phase, hair enters the catagen phase, a short transitional period that lasts about one to two weeks. During this time, the hair follicle shrinks to approximately one-sixth of its normal length. The lower part of the follicle is destroyed, and the dermal papilla detaches, marking the end of active growth for that strand.

Telogen Phase – Resting Phase

The final stage in the hair growth cycle is the telogen phase. This resting phase usually lasts around 5–6 weeks. Roughly 10–15% of all hair on the scalp is in the telogen phase at any given time. During this period, the hair is no longer growing but remains anchored in the follicle while the dermal papilla rests below.

At the end of the telogen phase, the hair follicle re-enters the anagen phase of hair, restarting the cycle. The dermal papilla and the base of the follicle reconnect, and a new hair begins to form. If the old hair has not already shed, it will be pushed out by the new strand, continuing the rhythm of the hair growth cycle.