Almost all hair loss in guys results from male-pattern baldness, a genetic trait that comes from your parents. Other causes include certain medications, too much vitamin A, or not enough protein. Illness or stress can lead to sudden, heavy shedding called telogen effluvium. Good news, though: Hair loss that isn’t from male-pattern baldness often reverses itself.
If you think over-the-counter hair loss shampoos are for you or just want to promote growth and strength, Dr. Schwieger recommends formulas with antioxidants such as vitamin E and ginseng, amino acids, and B-vitamins to help rebuild hair and reduce environmental damage. She cautions against those with parabens, sulfates, and fragrances, which can irritate hair and reduce moisture. Ahead, eight vetted hair loss shampoos to try.
To us, that meant any product with zero proven ingredients, case studies, or FDA clearance — which shrunk our list by a whopping 180 contenders. That’s right, there are only three treatments that have actually been cleared by the FDA and supported with clinical studies: finasteride (commonly marketed as Propecia), minoxidil, and laser treatments. And, since finasteride is prescription-only, it left us with two.
In either sex, hair loss from androgenetic alopecia occurs because of a genetically determined shortening of anagen, a hair's growing phase, and a lengthening of the time between the shedding of a hair and the start of a new anagen phase. (See "Life cycle of a hair.") That means it takes longer for hair to start growing back after it is shed in the course of the normal growth cycle. The hair follicle itself also changes, shrinking and producing a shorter, thinner hair shaft — a process called "follicular miniaturization." As a result, thicker, pigmented, longer-lived "terminal" hairs are replaced by shorter, thinner, non-pigmented hairs called "vellus."