You may notice when in the shower or brushing your hair that some of your hair seems to be falling out. How much hair loss is normal? People may shed between 50-150 hairs a day as part of the normal hair growth cycle. We will discuss when hair loss is normal and when it may be a cause for concern.

Normal Hair Loss Cycle

Our hair follicles are formed in utero as embryos. As we grow, so does our hair. Throughout our lives, hair growth and loss happens in three stages: anagen, catagen, and telogen.

• Anagen: During this growth phase, follicles will produce an entire hair shaft from tip to root.

• Catagen and Telogen: These are resting phases of the hair follicles.

• Telogen to Anagen Transition: A new hair shaft forms in the follicle next to the existing hair shaft. The new hair forces the existing hair to be shed and will emerge from the same follicle as the previous once.

This routine process ensures that hair remains healthy. Minor, regular hair loss is simply part of the growth cycle and is no cause for concern.

When Hair Loss Is Not Normal

Many conditions can cause temporary excessive hair loss:

• pregnancy

• medication

• vitamin deficiency

• scalp infections

• thyroid problems

When these conditions are properly treated or come to a natural end, excessive hair loss generally ceases and normal growth returns.

Some causes of hair loss are more permanent. Behavioral disorders such as hair pulling, alopecia areata, or diseases which cause scalp scarring, can lead to permanent hair loss.

Your genes can also play a large role in permanent hair loss. Male pattern baldness is caused by genes and a change in male sex hormones. The hair follicles begin producing smaller, thinner hairs and eventually cease producing hair all together. The actual follicle, though, remains alive. The typical pattern of hair loss begins with a receding hairline that may form an “M” shape. Over time, the hair on the crown of the head will dissipate leaving a “U” shaped hair pattern.

Female pattern baldness is different from that of their male counterparts. Hair loss generally begins along the part and doesn’t follow the same “M” pattern. Female pattern baldness rarely progresses to total baldness as male pattern baldness can. The reasons for female pattern baldness are not well understood but are thought to include aging, changes in male hormones, and family history.