What the letter says, who writes it, how to ask for one, and what to do with it once you have it.
If you want to pay for a personal trainer with HSA or FSA money, you'll almost always hear the same four words: Letter of Medical Necessity. This guide explains what an LMN is, what goes in one, who can sign it, and how to ask your doctor without it feeling awkward. HipTrain wrote it. We're HSA / FSA eligible, but we don't write these letters, and we can't promise your plan will accept one.
A Letter of Medical Necessity (LMN) is a note from a licensed healthcare provider saying a treatment, here personal training, is needed for a specific diagnosed condition. It lists your diagnosis, the training recommended, how often and for how long, and why it's medically necessary, and it's signed and dated by the provider. Under IRS rules, exercise for general health doesn't qualify, so the letter is what links training to treatment. Most LMNs are valid for about a year.
HSAs and FSAs can only pay for qualified medical expenses. IRS Publication 502 says that excludes things "merely beneficial to general health" and health club dues. It does allow amounts paid to lose weight when that's treatment for "a specific disease diagnosed by a physician (such as obesity, hypertension, or heart disease)." The IRS FAQ on wellness expenses adds that exercise for general health doesn't qualify "even if recommended by a doctor."
That last line is why a quick "you should exercise more" from your doctor isn't enough. The letter needs to show the training is part of treating a diagnosed condition. For FSAs, Pub 969 also requires a written statement from an independent third party to back up each expense, and administrators commonly ask for an LMN for expenses that are only sometimes eligible, like exercise.
Benefits administrator WEX lists these parts. Your plan may have its own form with the same fields.
Here is what the key line might look like. This is only an example of the kind of wording providers use. Your provider writes the actual letter in their own words, based on your health.
Example: "I am treating [patient] for [diagnosis]. I recommend supervised exercise with a certified personal trainer, 2 sessions per week for 12 months, as part of treatment for this condition."
A licensed healthcare provider who knows your health. WEX says that can be a doctor, a specialist or another licensed medical professional. Truemed lists physicians, nurse practitioners and physician assistants. A personal trainer cannot write or sign an LMN, and neither can a fitness company's sales team.
Yes. Third-party services exist that connect you with a licensed clinician online. Truemed, for example, describes a process where you complete a health survey, a licensed provider reviews it, and, if appropriate, they issue a letter. Some fitness companies partner with these services. It can be faster than waiting for an appointment. We don't endorse a particular service. Whichever route you take, the letter has to reflect a real diagnosis, and your plan still decides whether to approve the claim.
HipTrain is live 1-on-1 personal training over video with the same certified coach every session, and HipTrain is HSA / FSA eligible. If your provider asks what the training involves, you can tell them: scheduled live video sessions of 30 or 60 minutes, once to three times a week, with a coach who watches your form and adapts exercises in real time. Plans start at $59.49 a month for one 30-minute session a week, about $14 a session, and 60-minute sessions work out to about $25. Your first session is free, no card needed.
"Great option to do a virtual workout with a 1:1 trainer. Angel is great at adapting exercises to my needs." (Emma S., Google review)
What we don't do. Our coaches are certified personal trainers, not doctors, physical therapists or dietitians. We don't issue LMNs, bill insurance or offer nutrition coaching. If you're recovering from surgery, your provider may want you in physical therapy first.
For the rules that apply to each account type, see our guides on using an HSA for a personal trainer and using your FSA before it expires.
No. It's the main document plans look for, but your administrator decides, and IRS rules still require a specific diagnosed condition.
No. It must come from a licensed healthcare provider, such as your doctor, a specialist, a nurse practitioner or a physician assistant.
The IRS names obesity, hypertension and heart disease as examples of diagnosed diseases where a weight-loss program can qualify. Your provider decides whether exercise is part of treating your condition.
Usually about a year, per WEX. Some plans need a new one sooner, so check yours.
It depends on your plan. Some want it attached to claims, others keep it on file. Always keep your own copy with your receipts.
Want to try live coaching while you sort out your letter? Book your first HipTrain session free. No credit card needed.
We checked these rules in October 2026. Plan requirements change, so confirm with your HSA or FSA administrator.