…if there’s a difference in deodorant efficacy between shaved and unshaved armpits. I could see it going either way, although I lean towards the theory that shaved + deodorant is perhaps slightly more effective. Why?
Less stinky because fewer hairs for sweat and stink bacteria to adhere to
Less stinky because deodorant goes directly onto skin
More stinky because less area for deodorant to stick
Less stinky because more area for deodorant to stick (all those hairs)
More stinky because hair insulates skin from getting directly deodorized
More stinky because more hairs to sweat and stink bacteria to adhere to
It wouldn’t be very difficult to test this question, but you would need an objective stink-o-meter to measure armpit stinkiness, since (a) you couldn’t ask evaluators to sniff lots of armpits; and (b) human evaluators would be too subjective, anyway. Sadly, I somehow doubt this question will ever be seriously researched, so it’s likely to remain forever in the realm of speculation. Which, come to think of it, may be for the best.