References:
Daniels G, Akram S, Westgate GE, Tamburic S. Can plant-derived phytochemicals provide symptom relief for hair loss? A critical review. Int J Cosmet Sci. 2019;41(4):332–45.

Anna Chacon, M.D.
Dermatology Times, Dermatology Times, November 2020 (Vol. 41, No. 11), Volume 41, Issue 11

Caffeine and Its Pharmacological Benefits in the Management of Androgenetic Alopecia: A Review. Völker J.M. · Koch N. · Becker M. · Klenk A.

Follicular Penetration of Topically Applied Caffeine via a Shampoo Formulation
Otberg N.a · Teichmann A.a · Rasuljev U.b · Sinkgraven R.a · Sterry W.a ·Lademann J.a