Dual-use products — wearables, supplements, gym memberships — can become HSA-eligible with a Letter of Medical Necessity. What an LMN is, what it must say, and how to keep it audit-proof.
A Letter of Medical Necessity is a licensed provider's written statement that a product or service treats or mitigates a SPECIFIC diagnosed medical condition — converting a dual-use expense (IRS Pub. 502's general-health exclusion) into qualified medical care for you specifically.
Anything 'Bucket B' in Candor's eligibility database: fitness trackers and smart rings, supplements beyond prenatal vitamins, gym memberships and exercise equipment, massage therapy, weighted blankets, air purifiers, weight-loss programs. The pattern: products healthy people also buy. Directly eligible items (Bucket A) never need one; cosmetic items (Bucket C) can't be rescued by one.
The diagnosis or condition being treated; the specific product or service recommended; how it treats or mitigates that condition; duration of the recommendation; and the provider's license information and signature. Vague 'wellness' letters that don't name a condition are weak audit defense.
Get the LMN BEFORE the purchase — a letter dated after the expense invites the argument that the purchase wasn't medically motivated. LMNs should be renewed (annually is the norm) for ongoing expenses like memberships or subscriptions.
An LMN is audit-defense paperwork: it only works if you can produce it alongside the receipt, possibly decades later under the shoebox strategy. Candor stores both together against the expense.
Candor vaults your receipts, tracks your Claimable Balance, and answers eligibility questions with IRS citations — free.
Start your shoebox — freeInformational only — not tax, legal, or medical advice. Consult a qualified tax professional about your situation. Rules version 2026-07-16, last verified July 2026.