Btw I started applying lotion around 16 weeks but you can start whenever
I just got bio oil (a little pricey from Walgreens) so far I really like it I'm not sure if it will really get rid of/prevent stretch marks but it is making my skin soft and hydrated so it's worth a shot :)
Cocoa butter is actually not recommended because it has caffeine in it and can affect the baby I use actual baby lotion like Johnson and Johnson
I started as soon as I found out I was pregnant (5 weeks) and them I found out I was having twins and really started to lather it on. It won't hurt to start ASAP. I use palmers cocoa massage lotion and Burt's bee mama belly butter i think it's called.
I was probably around 20 weeks. Once my belly really started to stretch. ☺i use the Vaseline cocoa butter lotion.. Absorbs a lot faster and smells better in my opinion