Does caffeine inhibit Minoxidil's beneficial effects on hair?

This this is an interesting question. Cox inhibitors such as aspirin have been known to adversely affect topical minoxidil. Topical caffeine has been shown to be a DHT inhibitor and therefore assist in hair growth.therefore you have opposing actions. The stimulatory effect of the caffeine on dht and inhibitory effect on sulfotransferase needed to convert minoxidil. Has no Studies have been performed it's difficult to determine the actual effect. 

Both Caffeine and Minoxidil when applied to the scalp, can induce hair growth. In a recent study in a peer reviewed journal, the 2% caffeine and the 5% minoxidil were both equal in value when applied to the scalp topically.