Dehydrated hair is essentially a lack of moisture: Hair needs moisture to be smooth and hold style. Moisture is a foundational element that you need to replenish every day.

Moisture helps to keep the hair cuticle, the outermost layer of the hair shaft, smooth and intact, which in turn helps to prevent damage and breakage.

Exposure to heat, sun, wind, and poor-quality hair products can strip hair of its natural moisture and cause it to become dehydrated.