Stick with well-known national brands.
Supplements are one instance where you don't want to buy local. You're much better off sticking to well-respected national brands. That's not to say that a local or startup brand can't be decent, but bogus fly-by-night companies crop up all the time, and it's not always clear who's legit and who's not. The big national brands have reputations to uphold, so they're more likely to invest in solid research, proper manufacturing controls, and higher quality ingredients.