The Hair Loss Encyclopedia
proportion of thick hairs to fine hairs on the scalp
The Terminal to Vellus Hair Ratio refers to the proportion of thick, pigmented hairs (terminal hairs) to fine, short, and lightly pigmented or non-pigmented hairs (vellus hairs) on the scalp or other parts of the body. This ratio is often used in the diagnosis and monitoring of hair loss conditions like androgenetic alopecia, where a decrease in the ratio indicates a shift from terminal to vellus hair, signifying hair thinning and miniaturization.