What is a common sign of thermal hair damage?

A common sign of thermal hair damage is dry, brittle hair ends. When hair is frequently exposed to high heat from styling tools like flat irons, curling wands, or blow dryers, it can lose moisture and structural integrity. This results in the ends of the hair becoming dry and brittle, making them more prone to breakage and split ends.

While other options might appear as potential signs of hair damage, they are not as directly associated with thermal damage. Oily hair can indicate excess sebum production but does not relate to heat exposure. Frizzy hair may arise from various factors, including humidity or lack of moisture, but it does not specifically point to thermal damage. Excessive shine, on the other hand, can indicate healthy hair that is well-moisturized rather than damaged by heat. Thus, the distinct characteristic of dry, brittle ends serves as a clear indicator of thermal hair damage.