Where should you apply shampoo?
Mostly on your scalp. The American Academy of Dermatology says this cleans away oil, dead skin, and product buildup without drying out the length of your hair.
Why the scalp
Shampooing the scalp removes built-up products, dead skin, and excess oil. Putting it on the full length can dry hair too much.
Follow with conditioner
AAD says to use conditioner after washing. It moisturizes and detangles hair.
When to stop
Stop a product and see a board-certified dermatologist if you get burning, swelling, blistering, hives, or symptoms that get worse. Get urgent help for trouble breathing or swelling of the face or lips.
Source
Reviewed September 23, 2026. General education, not diagnosis or personal medical advice.