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What a Letter of Medical Necessity is — and what it is not

Education onlyNo letter service, ever

For the categories where the default answer is no but the rules leave room, a letter from a clinician is the mechanism that moves the answer. There is an entire small industry built on being vague about what that document is. This page is not vague about it.

Magellan does not write, sign, sell, review or arrange these letters.

There is no Magellan letter service, and there will not be one. This page exists so that you can walk into your own clinician’s office already knowing what the form asks for — nothing more than that.

In IR-2024-65 the IRS warned about companies selling doctor’s notes for a fee, stating that notes based merely on self-reported health information do not convert non-medical wellness expenses into medical care. If a website offers to sell you a letter for a flat fee after a questionnaire, the IRS has already told you in writing what it thinks of the resulting document.

Who can write one

Nobody can write this letter except a clinician who has actually evaluated you. What you can do is walk in with the paperwork already organised, so the conversation takes two minutes instead of twenty. The ledger tool in the Magellan app assembles those fields into a one-page request sheet you take to your own clinician, with the clinical judgement left blank where it belongs.

The six fields administrators look for

FieldWhy it is there
Your name and date of birthEvery administrator form starts here.
The diagnosed conditionNamed, specific, and diagnosed by a physician. Not "low energy" — the actual diagnosis. Many forms want an ICD-10 code.
The specific item, by nameItemised. "Supplements" is rejected; "magnesium glycinate 400 mg nightly" is not. A letter cannot bless a whole shopping cart.
How the item treats that conditionThe causal sentence. This is the part that is actually clinical judgement, and the part a questionnaire cannot manufacture.
Duration of treatmentStart and end dates. Most administrators cap a letter at 12 months and want it renewed annually; some read an undated letter as expiring a year after it was written.
Signature, printed name, credentials, licence number, phoneAn unsigned letter is not a letter.

Administrator forms typically also carry an attestation that the treatment is medically necessary for the named condition and is not for general health and not cosmetic. That sentence is doing real work — it is why a clinician cannot sign one for a supplement you are taking for general wellness.

Three things a letter cannot do

  • Submitting a letter is not approval. Your plan administrator makes the final call, and the IRS can look at it later.
  • A letter cannot make an ineligible expense eligible. It only documents medical necessity where the rules already leave room — protein powder stays out no matter who signs what.
  • Your own treating physician is the right person to ask, because they have the chart. That is not a formality; it is the whole basis on which the letter has any value.

The second of those is the one worth internalising. The letter documents medical necessity where the rules already leave room. Where the rules leave none — food and protein powder being the standing example — no signature changes the outcome.

Where a letter actually matters

Four categories in this project's reference data sit in the letter-required zone, and they are not equally well founded. Supplements are letter-required on the face of Pub. 502 itself — that is IRS-based. Exercise equipment is letter-required because custodians decided so; no IRS document addresses it at all. Knowing which of those two you are dealing with changes how much weight the letter is carrying.

CategoryMedical careCardBasis
💊 Dietary supplements & vitaminsLetter neededLetter neededIRS
🤰 Prenatal vitaminsLetter neededYesPractice
🦴 Glucosamine / chondroitinLetter neededYesPractice
🚴 Fitness / exercise equipmentLetter neededLetter neededPractice
🥗 Nutritional counseling / dietitianLetter neededLetter neededIRS
📦 Something elseLetter neededLetter neededPractice

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Education only — not tax, legal or medical advice. Magellan does not decide what your plan will reimburse, and Magellan does not write, sign, sell, review or arrange Letters of Medical Necessity. Eligibility depends on your own plan documents and your own circumstances: confirm with your plan administrator before you spend, and take tax questions to a tax professional. Figures on this page come from the IRS documents cited beside them; they change, so check the citation.