How It Works

Joining a Gym in January? Get the Letter in December (2026 Guide)

August 25, 2026 · 5 min read

Every January, millions of people join a gym. A fraction of them have diagnosed conditions that make that membership legitimately reimbursable with pre-tax HSA or FSA dollars — and most of that fraction loses the benefit for the exact same reason: they sign up first and think about documentation later. The order is the whole game.

The rule nobody reads until it costs them

Plans reimburse from the Letter of Medical Necessity's date forward. Months you paid before the letter existed are not reimbursable, and several administrators — Fidelity among them — look harder at memberships that predate the recommendation, on the sensible logic that you were paying for it anyway. A letter dated January 20 does nothing for the January 2 signup fee.

Flip the order and everything works: letter in late December, membership in January, and every month from the signup forward is claimable. On a typical membership, pre-tax dollars save 30–40%.

The December checklist

Confirm you have a genuinely qualifying condition — obesity, high blood pressure, prediabetes or type-2 diabetes, high cholesterol, osteoarthritis, chronic back pain, depression, anxiety. No condition, no letter; that is the IRS line, not ours
Get the letter — your own physician, or a same-day physician review through MedSlip
Check your administrator's specific rules — they differ more than people expect (see our guides for HealthEquity, FSAFEDS, WEX, Lively, Optum)
Join in January, pay out of pocket (your benefits card will decline at the gym — that is normal), keep itemized statements
Submit claims with the letter attached; renew the letter every 12 months

Why December is also the easy month to qualify honestly

A January fitness resolution and a medical need are not the same thing, and a legitimate physician review treats them differently. But the two often coexist: the person resolving to exercise in January frequently IS the person whose blood pressure, A1C, weight, or back pain a physician has flagged. If that is you, the review will support a letter. If it is not — if you are healthy and simply want a tax break — a legitimate service will decline you, and you should be suspicious of any that would not.

I already joined on January 2. Is it too late?

Not for the future. Get the letter now and claim from its date forward — you lose the early weeks, not the year.

Does the letter cover signup fees?

Administrators generally reimburse the membership fees for treatment periods after the letter's date. A signup fee paid before the letter is the classic loss the December timing avoids.

Which account does this work with — HSA or FSA?

Both, with different review mechanics: FSAs check the claim when you file; HSAs typically reimburse without upfront review and the documentation matters if the IRS ever looks. Our HSA vs FSA guide covers the differences.

Planning a January start?

Do the letter now. Free eligibility check, physician review, and a signed Letter of Medical Necessity the same day when appropriate — $69, refunded if no letter is issued.

Get my letter first →

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.

← More articles