Here is a common question: Will I lose all my hair after gastric bypass? How do I keep my hair from falling out? The reality is that hair loss after bariatric surgery is common. But patients do not lose all their hair. In the most severe cases, patients may find clumps of hair in their hair brushes, or in the shower drain. However the hair loss normally corrects itself. The most accepted explanation is inadequate protein intake. Hair loss tends to start about three to five months after surgery. The best way to prevent hair loss is to make sure that you take your proteins first, with each meal.
Hair loss after bariatric surgery is considered a type of Telogen Effluvium. To explain, we need to talk a little bit about the normal phases of the cycle of hair development. Each strand of hair goes through three stages of development. These stages are Anagen – the growing phase, Catagen – the intermediate or transitional phase, and Telogen – the resting phase.
Anagen (The Growth Phase): Lasts 2-6 years. About 85% of all the hairs are in the growth phase at any given period of time.
Catagen (The Transitional Phase): The outer root sheath of the hair follicle shrinks and stops producing hair. The catagen phase usually lasts 2-3 weeks.
Telogen (The Resting Phase) The hair does not grow at all. This phase lasts about 3 months (100 days). An average of 5-15% of all hair is in the resting phase at any given period of time. At the end of this phase, the hair follicle starts a new Anagen phase. The resting (telogen) hair remains in the follicle until it is pushed out by growth of a new anagen hair, unless it was shed earlier. There is some recent evidence suggesting that shedding of a telogen hair might be an active process, independent of an emerging anagen hair.
Telogen effluvium occurs when an event prematurely terminates anagen and causes an abnormally high number of normal hairs to enter the resting, or telogen phase. Not all hair enters the telogen phase, but the percentage is much higher than normal. The hairs that are shed due to telogen effluvium are in the telogen phase. Examples of such events include childbirth, gastric bypass surgery, crash diets with inadequate protein intake, acute blood loss, and high fever. Notice that the follicle is not diseased. Simply, the hair follicle’s biologic clock has been reset. On the average, telogen hair loss occurs 3 months after the event.
For the record, this is very different from another type of hair loss called "Anagen Effluvium". The latter is abrupt loss of hair in the anagen phase, which may be caused by cancer chemotherapy and irradiation therapy. This is very different from telogen effluvium.
In conclusion, hair loss after bariatric surgery (a form of acute telogen effluvium) is fully reversible. Patients never completely lose all their scalp hair, although the hair can be very thin. The hair follicles are not irreversibly affected. With restoration of the nutritional balance, helped by increasing the intake of proteins, hair regrowth is expected within 3 - 6 months.