Buying guide
Comparing shampoo bottles and multipacks
Match the exact formula and format before comparing bottle sizes or multipacks.
Compare shampoo with shampoo
These guides compare standalone shampoo. A 2-in-1 formula or a set with a separate conditioner is a different purchase; the conditioner’s volume should not count as shampoo.
Do the multipack math
Three twelve-fluid-ounce bottles contain 36 fluid ounces of shampoo. Divide the package price by the total volume, then check the exact formula and bottle size selected at checkout.
For dandruff, read the active ingredient
On medicated shampoos, Drug Facts lists the active ingredient and amount. Compare the same active and labeled strength before comparing price per fluid ounce; a percentage alone cannot compare different ingredients. An ordinary shampoo containing tea tree oil or salicylic acid is not automatically labeled to treat dandruff.
Follow the bottle’s directions, including how long to leave it on the scalp. Dandruff shampoos can have different instructions, and hair texture affects use.