What Qualifies for an HSA/FSA Letter of Medical Necessity? The Complete 2026 List

Adam Z. Kawalek, MD

July 4, 2026 · 7 min read

People ask me the same question about a dozen different products: "can my HSA or FSA pay for this?" The answer usually depends on one document, the Letter of Medical Necessity. This is my complete 2026 catalog of what an LMN can genuinely make eligible, what it sometimes can, and what it never will. Straight answers, category by category.

How a letter turns "wellness" into "medical"

HSAs and FSAs can only pay for medical care as the IRS defines it in Section 213(d) of the tax code: expenses for the diagnosis, cure, mitigation, treatment, or prevention of disease. A purchase that is merely good for you does not count. IRS Publication 502 is explicit that general-health purchases, like health club dues for staying in shape, are personal expenses.

The exception is what this whole page is about. When a licensed physician documents that a specific purchase treats a specific diagnosed condition, that purchase can become medical care. The document that records this is a Letter of Medical Necessity (LMN). One rule decides every category below: the expense must exist to treat a diagnosed condition, not to support a healthy lifestyle. Tax professionals call it the "but for" test. But for the condition, you would not be buying it.

With that rule in hand, here is the honest catalog.

The catalog: what an LMN can (and cannot) make eligible

1. Gym membership

Can it qualify? Yes, and it is the classic case. Publication 502 itself uses weight-loss programs for diagnosed obesity, hypertension, and heart disease as the example. A membership qualifies when a physician documents that structured exercise treats your diagnosed condition: obesity, high blood pressure, type 2 diabetes or prediabetes, high cholesterol, chronic back or joint pain, or anxiety and depression as part of a treatment plan. It does not qualify for general fitness. Full guide: the Letter of Medical Necessity for gym membership.

2. Home exercise equipment (Peloton, treadmill, walking pad, weights)

Can it qualify? Yes, on the same logic as the gym. The IRS cares why you exercise, not where. A treadmill or bike used to carry out physician-prescribed exercise for a diagnosed condition can be documented in an LMN. The hardware is the straightforward part; app subscriptions are murkier and vary by administrator. Details and the equipment list: is home gym equipment HSA/FSA eligible.

3. Personal training

Can it qualify? Yes, when the training is how a prescribed exercise program actually gets done, for example supervised conditioning for a bad back, cardiac rehab follow-through, or obesity treatment. The letter should name the condition and describe the training as part of managing it. General coaching for a healthy person does not qualify.

4. Massage therapy

Can it qualify? Often, for the right reasons. Chronic back or neck pain, injury rehabilitation, and specific musculoskeletal conditions are genuine LMN cases. A spa day for stress relief is not. Administrators see a lot of wellness-spa claims, so a specific diagnosis in the letter matters more here than almost anywhere else.

5. Sauna and cold plunge

Can it qualify? Sometimes, and this is where I have to be careful with you. There are legitimate documented uses, for example heat therapy for chronic pain conditions. But this is also the center of recovery-culture hype, and administrators know it. A cold plunge bought because your favorite podcast swears by it will not survive review. If a physician can tie the therapy to a real diagnosis, an LMN is worth pursuing; if not, pay cash and enjoy it as a hobby.

6. Red light therapy

Can it qualify? Narrowly. There is reasonable evidence for certain skin conditions and joint pain, and those cases can support a letter. The "biohacking" uses, energy, longevity, general recovery, do not meet the 213(d) standard. Expect administrators to look closely at this category.

7. Weight-loss programs (WeightWatchers, Noom, and similar)

Can it qualify? Yes, this is one of the strongest categories. Publication 502 explicitly covers weight-loss programs as treatment for a diagnosed disease such as obesity, hypertension, or heart disease. The program fee can qualify with a letter. The food itself generally cannot, and a program joined for appearance rather than a diagnosis cannot either.

8. Wearables and sleep trackers (Oura, WHOOP, Apple Watch)

Can it qualify? This is the hardest category on the page, and you deserve the straight answer: usually not. A general-purpose device that tracks your life is a personal electronic, even though it measures health data. The genuine cases are narrow, for example physician-directed monitoring for a diagnosed sleep or cardiac condition, and even then some administrators still decline the claim. If a service promises your smartwatch is automatically eligible, be skeptical.

9. Standing desks, ergonomic chairs, and back-pain gear

Can it qualify? Yes, for documented musculoskeletal conditions. Chronic lower-back pain with a physician recommending ergonomic correction is a textbook 213(d) case. Working from home more comfortably is not. The letter should name the diagnosis and the specific equipment.

10. Vitamins and supplements

Can it qualify? Mostly no, and I would rather tell you that now than after you buy a cabinet full. General multivitamins for wellness are personal expenses, letter or no letter. The exceptions are specific: a supplement prescribed or recommended to treat a diagnosed deficiency or condition, for example iron for diagnosed anemia or vitamin D for a documented deficiency. The diagnosis is what does the work.

What never qualifies

No letter can make these eligible, and you should walk away from anyone who says otherwise:

• Anything bought for general health, fitness, appearance, or performance with no diagnosed condition behind it
• Groceries and everyday food, including "healthy" food
• Cosmetic purchases and procedures
• A product you would honestly buy anyway, condition or not, where the letter is just paperwork after the fact

This is not my opinion; it is the IRS position. In 2024 they warned specifically about companies selling doctor's notes that claim to convert any wellness purchase into a medical expense. A letter without a genuine diagnosis behind it does not protect you in an audit. A letter with one is exactly the documentation the rules contemplate.

How the letter gets written

A real LMN is a clinical determination, not a form letter. A licensed physician reviews your health history, confirms a qualifying diagnosis applies to you, and signs a letter naming the condition, the recommended item or service, how it treats the condition, and the duration, usually 12 months. You can ask your own doctor at your next visit, or use an online physician service. At MedSlip, I review every request personally: $69, usually same day, and you are not charged if I cannot issue one. Either route works; what matters is that the review is real. The full breakdown of the document itself is in our Letter of Medical Necessity guide.

Getting reimbursed once you have it

The letter plus an itemized receipt is the pair that does the work. Submit both to your FSA administrator, or keep them on file and reimburse yourself from an HSA. The mechanics differ a little between the two accounts, including what happens if a claim is questioned; the step-by-step is in how an LMN actually gets you reimbursed. If you are deciding between account types first, start with HSA vs. FSA. And if you are holding FSA money late in the year, mind the use-it-or-lose-it deadline.

This article is for general information and is not medical, tax, or legal advice. IRS rules and administrator policies change and vary by plan. Confirm the specifics with your HSA or FSA administrator or a tax professional.

Adam Z. Kawalek, MD

Board-Certified Physician · Founder, MedSlip · Cedars-Sinai · Johns Hopkins

Dr. Kawalek is a board-certified internal medicine physician with 15+ years of clinical experience. He founded MedSlip to give patients fast, affordable access to the Letters of Medical Necessity that make fitness and wellness spending HSA/FSA-eligible.