Every cell in the body requires iodine. Toxic halogens like flouride, chlorine, and bromine will overtake and occupy iodine's spot in the cell. It's impossible to avoid said halogens, we're constantly being exposed to it (drinking water, tooth paste, bread, etc). Just think about this: every day you're constantly reintroducing chlorine into your body by drinking tap water, thus displacing iodine from your body. Obviously this includes the cells in your testicles. If your balls aren't working at 100% efficiency, then neither is your testosterone production. You're also likely not getting enough iodine in your diet. The RDA for iodine is 150mcg. That's absurdly small compared to average daily iodine intake in Japan which is 13.5mg. You're not gonna kick out the halogens from your body unless you take mg's. Back to the topic of "testicle painting". The idea is to transdermally apply iodine on your scrotum, which passes through the skin and goes directly to your testicles and leydig cells. I've tried it and here are my findings: harder erections, increased libido (after a couple hours I get the most powerful urge to bust a nut), semen more thick and creamy. I don't claim it boosts testosterone like all the other websites say, but it undoubtedly has a positive effect on the sexual organs. Here's a pdf where the protocol is further broken down: The secret that doubles testosterone Apparently the protocol requires a bunch of different vitamins/minerals, but I just take a multi and the iodine, still works fine for me. The iodine brand you want to use is "Lugols 2%", search on amazon. Hopefully you're not ignorant and disregard things just because they sound stupid, like @Michael Scally MD did on this same topic, otherwise you'll be missing out on a life changing hack.