Disruption is your answer. You have to make the product disruptive or the product be competitive with disruptive pricing. Some entrepreneurs have this myth that if they convince the potential investors to use their products then they can get the investment, however this is wrong. If you make cigarettes and your investors don't smoke then they will still invest in it, if it sells.

I can help you in making it disrupting, generating traction and hacking growth and then raising funds from the investors. Let' set up a call.

If you place a product in retail stores, you'll do this through an aggregator.

There are only a few in the US.

You'll likely have to discount supplements by 60%-80% of retail to interest an aggregator.

So likely your way better off selling directly to consumers.

Better meaning you'll require producing far less product for far more profit.

Consider using Facebook Ads or Traffic Oxygen or Kickstarter for product testing.

Sell product through Amazon FBA, if you prefer to avoid fulfillment challenges.