Letters of Medical Necessity

What an LMN is, how to get one, and what it does and does not cover.

A Letter of Medical Necessity is a note from a licensed clinician that explains why a specific item or service treats a specific medical condition. Plan administrators ask for one when a purchase is not automatically recognized as a medical expense, which covers most of what people actually want to buy.

The letter is not a purchase authorization and it is not a prescription. It is documentation. Your administrator still reviews the claim and makes the call, and the guides here are written to help you send them something they can approve the first time.

Burst writes the letter and files the claim for you. Your plan administrator pays the reimbursement out of your FSA, HSA, or HRA account to you. One letter is $35, flat, and it is refunded if the claim is not approved.

One rule worth knowing before you read anything else: a letter has to be dated before the purchase it supports. That is an IRS timing rule and it binds every provider, so getting the letter first is the difference between a claim that works and one that does not.

How to Get a Letter of Medical Necessity Online

Skip the doctor's office. Get a Letter of Medical Necessity online in 24–48 hours through a licensed provider. Here's how online LMN services work and what to look for.

How Can I Get a Letter of Medical Necessity (LMN)?

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What's A Letter of Medical Necessity (LMN)?

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The Complete Letter of Medical Necessity Guide (2026)

A Letter of Medical Necessity (LMN) is the single piece of paperwork that turns an everyday health purchase into a pre-tax FSA or HSA expense. This is the complete walkthrough: when you need one, what it has to say, what it covers, and how the reimbursement actually flows.

Letter of Medical Necessity FAQ: 30 Common Questions Answered (2026)

The 30 most common questions about Letters of Medical Necessity for FSA and HSA, answered in one place. What qualifies, what an LMN actually says, how reimbursement works, and the edge cases people get wrong.

Burst guide cover, for shoppers: the headline "What a real letter looks like" over the line "A full sample, annotated, and the parts plans reject letters for" with three tags: Full sample, 6 required parts, No templates.

Letter of Medical Necessity Sample: What a Real One Says

A full sample letter of medical necessity, explained section by section, plus why blank templates get denied and how specific the item must be for your plan.

What Is a Letter of Medical Necessity (LMN)? The Complete Guide

A Letter of Medical Necessity (LMN) unlocks FSA and HSA funds for wellness purchases like gym memberships and fitness equipment. Learn what an LMN is, what it includes, and how to get one.

The Ultimate Guide to Letters of Medical Necessity (LMN)

You have an FSA or HSA and want to know everything about letters of medical necessity (LMNs), when to secure one, and what to do after you have one.

What's the Difference Between a Letter of Medical Necessity (LMN) and a Prescription (Rx)?

Learn the key differences between an LMN and an Rx - both are doctor's notes, but when it comes to what they're used for, they're quite different.

Person preparing reimbursement paperwork

How to Buy Pre-Tax with an LMN: The Complete Walkthrough (2026)

Step-by-step: how to actually buy a Peloton, Tonal, mattress, or any LMN-eligible product with FSA/HSA dollars. The full process from purchase to reimbursement, with examples for the major plan administrators.

Burst guide cover, for shoppers: the headline "Get a letter of medical necessity" over the line "Your doctor, a telehealth visit, or online for $35, compared" with three tags: $35 flat, Same day, Any store.

How to Get a Letter of Medical Necessity (2026 Guide)

Who can write a letter of medical necessity, what it costs, what it must say, and how to use it to get reimbursed from your FSA or HSA at any store.