I bought 70% unbuffered glycolic acid off of amazon. You use this AT YOUR OWN RISK!!! I was using 10% lotion from a trusted beauty brand on my face at night. I read it encourages collagen production and reduces wrinkles. Well why not stretch marks?
Abdominal skin is no where near as sensitive as facial skin. I applied it full strength for 6 minutes. It was pretty hot, I had to keep my blow dryer on cool. It caused part of my belly button to burn, otherwise no problem, no scaring. I have used it twice on my face diluted with water about 50/50. I keep it on for 3 minutes and wash it off. My face is silky soft, tight, small pores, no peeling, minimal redness lasts only that day. I immediately apply cetaphil lotion afterwards. I do not put it near my eyes where "crows feet" would be, that area can't even handle the 10% lotion.
I am 24 so I cannot comment on it's "anti wrinkle" abilities, and it is too soon to see a difference in my abdomen. You need to be really careful and as educated as possible when doing these at home.