Beard hair growth, clearly, are susceptible to androgens, Idem to sexual hair, which needs androgens to growth.
http://www.sciencedirect.com/science/article/pii/0039128X71900511
In this study:
http://www.ncbi.nlm.nih.gov/pubmed/24244503 aldso with full free study
talk about senescence effect of androgens, but with differences between beard and baling jairs
We foundthat DHT induced premature senescence significantly in the DPCsfrom both transitional zone of balding scalp and non-baldingfrontal scalp. In contrast, neither beard DPCs (passage 2) norDU145 cells became senescent after exposed to DHT 0.1 mM
