Shedding a small amount of hair each day is normal. In fact, minor hair loss often is a sign that the body is growing new, healthy hair to replace old hair. But there may be cause for concern when more than 100 hairs per day are caught in the bristles of a brush or at the bottom of the shower drain. If a person is suddenly seeing more scalp or if hair feels less thick than it once did, he or she may be losing more hair than is normal, according to Francesca Fusco, M.D., a dermatologist and assistant clinical professor of dermatology at Mount Sinai. Getting to the root of the problem may take some time, but people can learn about common causes of hair loss to determine what might be the issue. Stress The National Institutes of Health reports that long-term or chronic stress puts people at risk for a number of health problems, including hair loss. A Harvard University study led by Dr. Ya-Chieh Hsu found increased corticosterone levels secreted by adrenal glands that occurred from mild to moderate stress affected hair regrowth in mice. Stress caused hair to gray or fall out in mice, and further study is needed to determine if there is a similar connection in humans. Genetics Both men and women are susceptible to hair loss due to genetics. The American Academy of Dermatology says hair loss is more likely to affect men along the hairline. In women, hair loss is usually concentrated at the crown of the head, especially noticeable at the hair part. There is no way to prevent this type of hair loss, but there are topical treatments that may slow down hair loss and make hair appear fuller longer. Hormones Hair loss can result from hormonal changes that occur when going on or off hormonal birth control methods or changing products. In addition, pregnancy causes surges in estrogen that cause hair to grow rapidly without falling out. However, after pregnancy, hair patterns return to normal growth cycles and mild to intense hair shedding for a few months may occur. Vitamin deficiency or overabundance According to the AAD, overconsumption of supplements that contain vitamin A or certain medications may trigger hair loss. People who are not getting enough protein also may experience unwanted hair loss, as might those who have low iron levels. Hair loss can be unsettling. Though it’s often natural, certain instances of hair loss should be brought to the attention of a physician. TF218169 SOCIAL MEDIA TEXT: Getting to the root of the problem may take some time, but people can learn about common causes of hair loss to determine what might be the issue.