I was considering only being able to imbue common chemical properties, and anything more unique both takes much longer and has to be learned either from prolonged exposure to a similar ability (such as getting buddy buddy with a speedster to learn how to make a potion that increases speed by 50%) or by ingesting blood from someone with a similar ability (but I understand if that part is a bit too morbid).

Obviously someone with a specific power is always going to be stronger than a potion, so my character would be a "jack of all, master of none" deal at best.