I'm not sure, but requirements may vary with the medical spending account so if you have an account through your employer go through all the small print.
I can point out some oddities in my own medical spending account, but am not sure all accounts are the same. For example, the account I have will reimburse for OTC medications like aspirin and eyedrops, but not for any vitamins or nutritional supplements. The fees I paid for a nutritionist consultation were reimbursed, but I could not get reimbursed for any vitamins or nutritional supplements the nutritionist recommended I take to help with MS. Even the CoQ10 recommended by a doctor to take with statins was not eligible, although if I got a "prescription" it might have been. The only exception to vitamins in my account program is apparently vitamins for pregnant women, but I could be wrong. I believe chiropractor or massage therapy is covered (haven't used those), but don't believe exercise classes are, even if recommended by a doctor. However, physical therapy with a physical therapist is covered.
The bias against including vitamins and nutritional supplements is really odd, in my mind, because to me nutrition is such a vital part of health, and there have been some double-blinded studies showing the benefit of certain supplements for MS-related symptoms. I'm guessing that is to curb the use of rip-off "snake oil" products to lose weight. Or a pre-tax "health spa cruise" and other potential abuses. However, I don't understand the bias against allowing reimbursement for exercise programs. There is definitely a "pro-drug" but "anti-exercise" and "anti-nutrition" bias built into the medical spending accounts.