The normal cycle of hair growth lasts about two to three years, according to the FamilyDoctor website. Around 90 percent of hair on the scalp is growing at any time. It's normal to shed a small amount of hair each day, but excessive hair loss is considered unhealthy.
Hormonal Changes
Hormonal changes and imbalances in the body may lead to hair loss, according to MayoClinic.com. These imbalances may be a result of pregnancy, the discontinuation of birth control pills or an underactive thyroid gland. Hair may keep falling out for around three months and may take another three months to grow back.
Alopecia
According to the University of Maryland Medical Center, alopecia is a hair disorder that involves the thinning or loss of hair. Two forms of alopecia are possible: scarring alopecia, which occurs when hair follicles are destroyed; and nonscarring alopecia, which can be treated and reversed. Alopecia may involve hair loss all over the scalp or only certain areas of the scalp. Alopecia may be triggered from drug use, pregnancy or scalp radiation. Medications such as minoxidil or tretinoin may be used to treat alopecia. Vitamin C and herbal supplements may also be taken to treat or prevent alopecia, although evidence has not proven supplemental benefits.
Poor Nutrition
According to MayoClinic.com, having an inadequate amount of iron and protein in a daily diet may result in sudden hair loss. A vitamin that is important for keeping hair healthy is biotin. Biotin helps restore hair that is thin, dry or splitting, according to the University of Maryland Medical Center. Low amounts of biotin in the body may result in hair loss.
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