also FYI: things that cause breast growth...
Things that work:
Being a genetic girl
Prescription Estrogens and Progestins
Things that sorta work:
Gynomastea... but that fades and is not too substantial... if it is there might be an intersex condition present.
Being overweight... but that's not quite the same...
Things that work and don't work at the same time:
oversized implants, especially without first experiencing hormonal development...
Things that are only rumored to work:
Milk - some people think the added hormones in here have an effect but they don't.
Soy - same with milk, and recently even they discovered soy wasn't so super as it had long been rumored... so why ingest it? soy is so gross...
Bath oils - I seriously doubt this can do anything substantial
Quack claims and creams - often sold to exploit members of the TG/TS community... should never be believed.
Rubbing - I've heard this... ummm no... though it can stimulate blood flow and prevent breast cancer.
Hypnosis - while hypnosis can have therapeutic and emotional benefits... I seriously doubt there would ever be substantial physical development... if someone thinks so I am 99.9% sure it is a quack claim...
Those vacuum thingies - ewwwww. quack quack
Things that SHOULD work
Fukus, ghosts, aliens, little girls with glowy hands, zappy guns, unknown pink concoctions in labs, japanese video games, genies, arcane jewelry, cursed springs, magical girls, summoning circles, and nanomachines...