The Hair Growth Cycle

Hair typically grows one centimeter per month, resulting in approximately 6 inches of hair growth per year. Hair growth occurs in three distinct phases: the anagen, catagen, and telogen phases.

Anagen Phase

The anagen phase is the part of the cycle where hair actively grows. During this phase, the cells that make up the hair’s root will divide and grow. As the new hair forms, it will push up from the base of the follicle and emerge above the skin. This active growth phase will last somewhere between two to six years and is different for each person. Some people are not able to grow their hair beyond a specific length, and this means that they have a relatively short anagen phase. Other people might be able to grow their hair very long and quickly, which would mean that they have a relatively long anagen phase.

Hairs on different parts of the body also have different lengths of the anagen phase. Eyebrows and beard hair are normally known to have shorter anagen phases than scalp hair, meaning they are unable to grow as long.

Catagen Phase

The catagen phase is the part of the cycle where hair growth stops. The shaft of the hair shrinks and separates from the bottom of the hair follicle, yet it remains in place. This phase typically lasts around ten days, and is the shortest phase of the hair growth cycle.

Telogen Phase

The telogen phase is the part of the cycle where the hair sheds, and is known as the ‘resting’ phase. This is where the follicle is at rest in the scalp and is prepared to be shed. This phase should last around a hundred days, and between twenty five and one hundred telogen hairs are typically shed per day. A white bulb is formed at the base of the hair shaft, and you may see these at the root of the telogen hair once they have been shed.

Causes of Hair Loss

Male pattern hair loss starts with the process of miniaturization causing hairs to become thinner by hormonal changes in DHT or genetics.


As mentioned before, hormonal changes are the main cause of hair loss in men. Specifically, a hormone called dihydrotestosteron (DHT) may become too prevalent and shorten the anagen phase of hairs. This means that the hair does not have a chance to grow as long as before, and the telogen phase also is lengthened causing the hair to have longer periods of shedding. The hairs that continue to grow will typically be much finer.

The ways in which DHT affects a person’s hair varies from person to person. There may be more available DHT receptor sites at the hair follicle, the receptor sites might be more sensitive, more DHT may be produced locally: there are a variety of reasons why DHT causes more hair loss in some men than others.


Your chances of experiencing hair loss increases if there is another family member with hair loss. The extent of hair loss may differ between family members, and the genetic component of hair loss may come from either side of the family. Both the father and the mother have the ability to pass on genes which result in hair loss.

Signs and Symptoms

In some men the first signs of hair thinning may be seen around the temples. Others may see hair thinning start in the crown. Abundant shedding is a common sign of hair loss as well, and lost hair follicles may be seen in the shower or on a pillow. The stages of thinning may progress to where small empty spots are seen along the hairline and scalp, indicating that telogen hairs have not grown to replace the shedded hairs.

Norwood Scale

The norwood scale is a tool used to measure the extent of hair loss in men and the patterns of loss typically seen in patients. The position of the scale may be a helpful indicator of how many hair grafts are needed in transplant cases.

Excellence in the Art of Hair Transplantation

Hair transplantation is a hair restoration surgery that works by moving hair from the back and sides of your head to the thinning or balding areas on the top of your scalp.
Dr. Koher and the surgeons of Koher Medical are particularly experienced with this procedure, having over 35 years of experience and having performed over 15,000 hair transplants nationally and internationally.

If you’re looking for a solution to your hair loss, you can trust the surgeons and staff of Koher Medical to deliver a world class experience and state of the art cosmetic results. No matter what your hair loss situation, Koher Medical is ready and willing to offer our expertise and years of experience.