Can we use our flex spending on vitamins?

Vitamins or nutritional supplements (herbal or natural medicines) used for general health are not FSA eligible expenses. However, if vitamins are used to treat a medical condition, they may be eligible

the PA at my surgeon's office said they could be if considered a medical necessity (which he'd argue they are in our case). He offered to write a prescription for them for me to use, but it turned out I didn't need it since I used up all of my FSA funds by around October of that year...

You can use your FSA card to buy vitamins but it must be through a pharmacy that's able to accept FSA cards. We've been working on accepting them at The BariatricPal Store but it's almost next to impossible at the moment.