Best conditioner for sweaty workouts

Why it works

Conditioning agents (silicones, cationic surfactants, fatty alcohols)

Conditioners work mainly on the hair surface. Washing leaves hair with a negative electrical charge, and positively charged cationic surfactants, the backbone of most conditioners, bind to it and cut static. Silicones such as dimethicone and amodimethicone form a thin film that lowers friction between strands and shields them from abrasion, and fatty alcohols like cetyl and stearyl alcohol add body and slip. Reviews link this to less frizz, easier combing and less grooming damage. This is well-established cosmetic science, measured mostly in the lab, not consumer trials. Effects last until the next wash, and leave-on products can make fine, straight hair look oily or dull.

Hyaluronic acid and glycerin (humectants)

Humectants are moisturizer ingredients that draw water into the outer layer of skin and hold it there. Glycerin is regarded as the most effective humectant for hydrating the skin surface. Hyaluronic acid, a molecule the skin also makes naturally, is another humectant that dermatologists list for dry skin. Used on their own, humectants can pull water out of the skin into dry air and may even increase water loss, which is why well-made moisturizers pair them with occlusive ingredients that seal water in. They work best applied to damp skin after bathing.

Oily scalp and washing frequency

An oily scalp mostly calls for more frequent washing, not a special ingredient. In two studies of Asian participants without scalp disease, by a team including researchers from a shampoo manufacturer, people who washed 5 to 6 times a week were most satisfied with their hair and scalp, and daily washing beat once-weekly washing on every measure with no objective hair damage. A dermatology review agrees that regular washing with a well-formulated shampoo does not harm hair. Dermatologists suggest daily shampooing for straight hair with an oily scalp, focusing shampoo on the scalp. Caveat: the data come from one population, and dry or curly hair needs less washing.