There are some companies I know do white label supplements, I’m not in supplements but in cosmetics and health.
I know several clients/friends that did or still doing supplements on Amazon as FBA. You don’t need $50K to do that! What you need is think about not running out of inventory, so if you have not done white label before then just be careful and start slow to learn, you can PM me and I will give you some tips.
You will need to find a reputable supplier that can offer you low quantity to start so you don’t have to spend $$$ on your first order, have tons of inventory then you end up not selling much, let’s say you start with 300 bottles, each costs you $4-5, then you list the item at $29 on Amazon? And Amazon fee is 12-15%? (Not sure what is the latest fee structure in supplements) , add FBA shipping cost for the 300 units which may be around $70, add other fee expenses and then calculate your gross profit and see if it’s worth it to do this or not.
Now the issue is: what if you sell these 300 units in 4 weeks? Amazon does not like suppliers who run out of inventory so your product ranking going to sink forever, you need to check how many you are selling per day or per week and replenish the inventory based on that, and many people never get this right, it is complicated.
So, when you first order the 300 units this will cost you $1,500 and adding other expenses like shipping ... maybe $200? = let’s say the whole cost is $1,700, and let’s say you are lucky enough to sell 100 units in the first 4-8 weeks with gross profit $15 per unit ( assuming you don’t have many expenses other than the product cost plus shipping), you will get $1,500 back in the first 4-8 weeks, you need to save this money so you can re-inventory, you can’t just go spend it on a car! LOL. So I hope you get my point. And check to see if you financially able to invest in the first small batch of the order and keep a float for the first 6 months while you are scaling this up.
Also, keep in mind that you may not sell anything and end up losing the money you have invested in this project.