The "most" hydrating shampoo varies based on individual hair type and needs, but look for formulas containing ingredients like shea butter, argan oil, hyaluronic acid, and glycerin. These ingredients help attract and retain moisture, combating dryness.

Hydrating shampoos focus on attracting moisture from the environment into the hair shaft, often using humectants. Moisturizing shampoos, on the other hand, aim to seal in existing moisture and add emollients to smooth and soften the hair.

To hydrate extremely dry hair, use a hydrating shampoo followed by a deep conditioning treatment or hair mask weekly. Also, minimize heat styling and consider incorporating leave-in conditioners or hair oils into your routine for added moisture.

The best shampoo for extremely dry hair is one specifically formulated for dry, damaged, or moisture-deprived hair. Look for shampoos that are sulfate-free and rich in hydrating ingredients like natural oils, butters, and humectants to replenish moisture.