That all depends on your definition of work, otc IGF-1 isn't really up to the challenge for bodybuilding, its more of a general health support.
IGF-1 and most other growth factors are actually illegal for over the counter sales UNLESS the amounts of growth factors are in an extremely low quantity. So that $40 bottle at your local vitamin shop that says HGH on the front is not necessarily lying to you, they just arent telling you that there is about a tear drop worth of HGH in a swimming pool of oral inocuous spray solution.
The amounts are high enough to apparently cause some kind of positive health benefits but from the perspective of Hypertrophy, you can do much better with your money. Its all your parogative homie.
Also, the FDA has a nasty habit of making amazing products illegal (thereby relegating their sales revenues to semi-evil pharmaceutical companies) while leaving nasty unhealthy products readily obtainable (this is why we can all buy liver toxic, methylated steroids but not relatively benign and effective ones like winstrol, etc.). Thus, the IGF-1 you'll get your hands is not only tuned down heavily, it most likely contains "long R3 Igf-1". This compound has been linked to so called "HGH-gut" or basically, enlarged internal organs. In one study it increased intesinal mass by a mean of 20%! Thats rediculous, you don't want to gain 3 or 4 pounds of intestines im sure.
If you can get real, pharmaceutical, non long r3 Igf-1 I would say go for it because apparently it hasnt shown the same propencity for organ growth but I personally wouldn't plan to invest much in super diluted organ grower in a body spray bottle.
Im a good read but I don't have first hand experience, anyone digress?