What is hair loss?

The normal cycle of hair growth lasts for 2 to 3 years. Each hair grows approximately 1 centimeter per month during this phase. About 90% of the hair on your scalp is growing at any one time. About 10% of the hair on your scalp, at any one time, is in a resting phase. After 3 to 4 months, the resting hair falls out and new hair starts to grow in its place.

What causes hair loss?

• Family history. In most cases, hair loss is inherited, which means it's passed down from one or both of your parents. This is called male-pattern or female-pattern hair loss.
• Stress, including physical stress from surgery, illness, or high fever.
• Chemotherapy, which is powerful medicine that destroys cancer cells.
• Damage to your hair from pulling it back too tightly, wearing tight braids or ponytails, or using curling irons or dyes.
• Age. You grow less hair as you get older. Hair also gets thinner and tends to break more easily as you age.
• Poor diet, especially not getting enough protein or iron

How much hair loss is common?

Everyone loses some hair every day. Losing up to 100 hairs a day is normal.

But if hair loss runs in your family, you could lose a lot more hair. With this kind of hair loss, you may end up with bald spots if you are a man. If you are a woman, you may find that the hair on the top of your head is slowly thinning. About half of all people have this type of hair loss by around age 50.

What are the symptoms?

Your symptoms will depend on what kind of hair loss you have.

If your hair is thinning, it happens slowly over time, so you may not notice the hairs falling out. If your hair is shedding, then clumps of hair fall out. You may lose hair all over your scalp, which is called general hair loss. Or you may lose hair only in one area, which is called focal hair loss.