We use a liposomal caffeine in our RevivScalp. "Liposomal" in that the caffeine is encapsulated in a phospholipid to containerize it. With a liposome we can enhance the delivery of caffeine to maximize its ability to effectively penetrate the stratum corneum, boosting its efficacy, strength and bioavailability.
Here are some published scientific articles:
Differential effects of caffeine on hair shaft elongation, matrix and outer root sheath keratinocyte proliferation, and transforming growth factor-β2/insulin-like growth factor-1-mediated regulation of the hair cycle in male and female human hair follicles in vitro.
Effect of caffeine and testosterone on the proliferation of human hair follicles in vitro.