Burst vs Truemed vs Flex for Shoppers (2026)
Burst vs Truemed vs Flex for shoppers: one handles everything, letter to refund. The other two handle one step. Who files, who appeals, what gets refunded.
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Short answer
Burst handles everything. Truemed and Flex handle one step. Tell Burst what you're buying, a licensed clinician writes your Letter of Medical Necessity, then you buy anywhere, on any card. Burst files the reimbursement claim with your administrator (the company that runs your FSA, HSA, or HRA), and if they push back, Burst writes the appeal. The letter is yours, so you can file it yourself if you'd rather. Most people let Burst do it, because Burst files faster, with fewer mistakes, and the way your administrator wants it filed. Your letter and your claim live with you, not with a store. $35 once. No letter, no charge. Claim denied, money back.
Truemed and Flex are HSA/FSA checkout options and marketplaces at brands that partner with them. At one of those brands, you pick their option at checkout, answer their health questions, get a letter if you qualify, and pay on your HSA/FSA card. If the store isn't one of their partners, there's generally no letter to get. And even at a partner, when the checkout doesn't take your HSA/FSA card, you're left to file the claim with your administrator yourself. Nobody at either company files your claim, and neither advertises an appeal or a refund if the claim is denied.
(Run a store, gym, or studio? The merchant version of this comparison is Truemed vs Flex for your business.)
Burst vs Truemed vs Flex, side by side
What matters | Burst | Truemed | Flex |
|---|---|---|---|
What it is | Handles everything: the letter, the claim, the appeal, the refund | Handles one step: a letter, at a partner brand's checkout | Handles one step: a letter, at a partner brand's checkout |
Where it works | Any store, gym, studio, or provider, online or in person | Their partner brands and marketplace; outside it, generally no letter | Their partner brands and marketplace; outside it, generally no letter |
Who files the claim | Burst files it for you, or you file it yourself if you prefer | Nobody; you're left to file | Nobody; you're left to file |
If your administrator pushes back | Burst writes the appeal | Not advertised | Not advertised |
If the claim is denied | Your $35 is refunded automatically | Not advertised | Not advertised |
How you pay | Any card you already use | Your HSA/FSA card at their checkout | Your HSA/FSA card at their checkout |
Recurring charges like gym dues | Covered under the same letter for 12 months and filed for you | Limited support | Limited support |
What you pay | $35 once; letter, filing, and appeal included | Varies by store and program | Varies by store and program |
The five differences that matter
Burst handles everything. Flex and Truemed only handle one step.
Getting reimbursed is several steps: the letter, the claim filed with your receipt in the format your administrator wants, the answer when they come back with a question, and the appeal if they say no. Truemed and Flex handle the first one, the letter, and only at a partner brand's checkout. Everything after that is yours. Burst handles all of it. You buy, Burst files the claim start to finish, and your administrator pays the reimbursement out of your FSA, HSA, or HRA to you. The letter is yours, and you can file it on your own if you want to. Most people don't, because Burst does it faster, gets the paperwork right, and files it the way your administrator asks for it, all included in the $35.
If your administrator pushes back, Burst writes the appeal
Administrators ask questions. Sometimes they say no the first time. Burst writes the appeal, every time, and it's included in the $35. Neither Truemed nor Flex advertises handling appeals. Once you have their letter, what happens next is between you and your administrator.
The refund is automatic
No letter, no charge. Claim denied, money back. Both happen on their own. If the clinician decides a letter isn't appropriate for you, you aren't charged. If your plan denies the claim, your $35 is refunded automatically. You can't pay Burst and get nothing. Neither Truemed nor Flex advertises a comparable guarantee.
Every item and service, not a partner list
Truemed and Flex only issue letters through brands that signed up with them. Their letter is tied to the partner's checkout, so if the store you're buying from isn't a partner, there's generally no letter at all. Truemed's own help center says it can't issue a standard letter for a non-partner purchase, with a short list of exceptions (gym memberships, saunas, exercise equipment, trackers) where it may issue a generic letter that you then file yourself. Burst has no partner list to check. Your gym, your massage therapist, a product from any store: the request form has a spot for any product or service, and a licensed clinician decides whether a letter is medically supportable for you. If it isn't, you don't pay.
A consumer platform, not a merchant plug-in
Truemed and Flex sell to brands, so you're using a store's payment option. Burst works for you, not for a store. Your letter and your claim live with you, and the same account works for the next thing you buy, from anyone.
What using each one looks like
Burst
Two minutes: name the product or service and answer a few questions about you. A licensed clinician reviews it and, if it's medically supportable, signs your letter, usually the same day and always within 24 hours. Then buy from any store with any card. Burst files the claim and your administrator pays you out of your account. Recurring charges, like monthly gym dues, stay covered under the same letter for 12 months.
Truemed or Flex
Both work the same way. Shop at one of their partner brands, pick their option at checkout, answer their health questions, and if you qualify, pay with your HSA/FSA card. Some partners don't take the card at checkout; there, you pay with a regular card, take the survey the merchant sends you, and if a letter is issued, you download it and submit it to your HSA/FSA administrator yourself. Shop anywhere that isn't a partner and, with a few exceptions, there's no letter. Their letter fees vary by store and program; Burst is $35 once, filing and appeal included.
When would you use Truemed or Flex instead?
If you're already at a partner brand's checkout with your HSA/FSA card in hand, their button is right there, and that's the whole case for it. Know the trade: nobody files the claim for you, and neither advertises an appeal or a refund. For most things you buy outside their partner brands, there's no letter at all. If you'd rather have someone who files the claim for you, get the Burst letter before you buy and pay however you like.
Frequently asked questions
Is Burst better than Truemed or Flex for a shopper?
Yes, because Burst handles everything and the other two handle one step. Burst writes the letter, files the claim, writes the appeal, and refunds the fee if the claim is denied, and it works wherever you shop. Truemed and Flex issue a letter at their partner brands' checkouts; the claim, the appeal, and the risk are yours, and buy anywhere else and there's generally no letter.
Can I file the claim myself instead of having Burst do it?
Yes. The letter is yours, and you can submit it to your administrator on your own. Burst's filing is included in the $35 either way, and it's faster and cleaner than doing it yourself: the letter, the receipt, and the dates go in the way your administrator wants them, and if they push back, Burst writes the appeal. That's why most people let Burst file.
Do Truemed and Flex file my reimbursement claim?
No. Both issue a letter only through a partner brand's checkout. Where the card is taken, the letter is stored for your records; where it isn't, you download the letter and submit the claim to your administrator yourself. Burst files the claim for you. Giving you a form isn't the same as making sure your claim gets handled end to end.
What happens if my administrator denies the claim?
With Burst, two things. First, if your administrator pushes back, Burst writes the appeal. Second, if the plan still denies the claim, your $35 is refunded automatically. Neither Truemed nor Flex advertises a comparable guarantee.
Can I get a letter for something I already bought?
No. IRS rules require the letter to be dated on or before the purchase it covers, and that binds Burst, Truemed, Flex, and everyone else equally. Get the letter first, then buy.
Do I need my own doctor?
No. A licensed clinician in the Burst network reviews your information. You don't need an existing relationship with a provider, an appointment, or a copay.
Does Burst work with my FSA or HSA administrator?
Yes. Burst works with every FSA/HSA administrator, including HealthEquity, Fidelity, WEX, HSA Bank, Inspira, Optum, and Further. Your administrator pays the reimbursement out of your account to you.
Get the letter first, then buy. We handle the rest.
$35 once, about two minutes, and a licensed clinician signs your Letter of Medical Necessity, usually the same day if approved and always within 24 hours. Then buy from any store with any card, and Burst files the reimbursement claim for you, start to finish. If your administrator pushes back, we write the appeal. 18,000+ letters issued. Works with every FSA/HSA administrator.
No letter, no charge. Claim denied, money back.
More for shoppers: How to Get a Letter of Medical Necessity Online, Can You Use Your HSA or FSA for a Gym Membership?, and How to Use FSA & HSA for Massage Therapy in 2026.
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