What can excessive heat do to hair?

Excessive heat exposure can significantly damage hair, leading to dryness and breakage. When hair is subjected to high temperatures, such as from styling tools like flat irons, curling wands, or blow dryers, it can strip the hair of its natural moisture. This process causes the hair cuticle, which is the outer protective layer, to become rough and damaged, ultimately making the hair more porous. As a result, the hair can lose its strength and elasticity, leading to split ends, frizz, and overall breakage.

On the other hand, other options suggest outcomes that are not typically associated with excessive heat. For example, while enhanced shine may occur with healthier hair, heat damage often has the opposite effect, making hair appear dull. Similarly, excessive heat is unlikely to increase moisture; instead, it dehydrates the hair. Lastly, while healthy hair can grow well, excessive heat does not promote hair growth and can instead hinder it due to the associated damage. Therefore, the correct understanding is that high temperatures can lead to detrimental effects on hair health.