Many runners have problems with chafing on the inside of the thighs, around the arm pits, and on the nipples. For a short run, that’s not usually a big issue, but for a longer run it can make finishing a run impossible. The first line of defense is proper clothing. If you’re concerned with friction between your thighs, wearing a pair of compression shorts or a pair of 2-in-1 short/compression shorts can make a big difference. Having a good shirt made of technical fabrics can also help, especially if you find a shirt that has no side seams to rub.
Body Glide is a favorite of runners. The original product is great for general anti-chafing use. Use it everywhere that you might chafe, particularly if you are planning a longer run.
Another specific product to protect against the sensitive area around the nipples is NipGuards. These little protectors keep the dreaded bloody nipples at bay.
Blister prevention and treatment
Blisters when running are a real problem if you’re not prepared. There are many things that can help prevent blisters, including having a pair of shoes that fit correctly, socks that are both a good fit and made with wicking material to pull moisture away from your foot, and products that are designed especially to protect your feet from friction. There are several such products on the market.
Body Glide has a specific product for foot care but the standard product is also very good at protecting against the friction that creates blisters.