I looked over the weekend into this topic. To make supplements work, you need volume, influencer have volume, gym owner don't. Profit margins are to thin, without private label. For private label, i think you need around 30k... and yes, it still looks like that you want them to buy your stuff all the time, when there are 100 of options out there, that might be on the same lvl or even better from the quality standpoint. On the other hand, you also can’t ignore the fact that there are gyms that make a decent profit from their protein drinks. However, a slightly different business model is behind that. Of course, one could also try to establish a monthly membership fee that includes the delivery of “supplements.”The question is whether that would actually be beneficial. It’s likely that some members would end up canceling because the total monthly cost becomes too high, which could quickly shrink potential revenue again. In the end, you might just have significantly more work but not much more money in your pocket. In the medical field—at least here in Germany—this model would also be quite problematic. I think it would be more reasonable to offer an online nutrition & supplement course for those who are genuinely interested. This also increases your authority, rather than making it look like you’re dealing drugs.