I like many of my fellow male runner suffered from the torment of nipple chaffing every time I ran.
I tried bodyglide, vasaline, etc. That didn't work, just stained my tops.
The solution... 10mm circular plasters!! Placed carefully even avoids chest hairs.
The problem is you only get a few in variaty packets, so I now have a lifetime supply of other plasters.
Surely one of the first-aid/plaster companys should of picked up on this obvious market.