Losing sleep over your receding hairline or thinning mane? You're not the only one. Many people put tremendous stress on their hair. Hair dryers, hot curlers, hair dyes, permanent and hair straightening products, and chemical-laden cosmetics may cause dry, brittle, and thinning hair. By the age of 35, two-thirds of American men will experience some degree of considerable hair loss, according to the American Hair Loss Association.