Your Sauna Might Be HSA-Eligible. Here Is What That Actually Means.

Browse any sauna brand’s website in 2026 and you will find a button that was not there two years ago: Pay with HSA/FSA. The pitch is simple. Use your pre-tax health savings dollars on a sauna and save 30 to 40 percent. Sun Home Saunas, HigherDOSE, Plunge, Sunlighten, and Sauna Republic all advertise it. The checkout buttons are live. The savings claims are posted in bold.

The pitch is not wrong, exactly. But it is not as simple as a coupon code.

Saunas are not on the IRS standard list of qualified medical expenses. They become HSA or FSA-eligible only when a licensed provider issues a Letter of Medical Necessity (LMN) tying the purchase to a specific diagnosed condition under IRC Section 213(d). That eligibility is per-person, condition-dependent, and never guaranteed to survive a plan administrator’s review or an IRS audit. Three companies have built businesses around bridging that gap: Truemed, Flex, and SaunaLMN. Each takes a fundamentally different approach to the same legal question. And the IRS, as of March 2024, has made clear it is watching.

How the letter of medical necessity works

The legal foundation is straightforward. Section 213(d) of the Internal Revenue Code defines “medical care” as amounts paid for the diagnosis, cure, mitigation, treatment, or prevention of disease. If a licensed healthcare provider determines that a sauna is medically necessary for a patient’s diagnosed condition (cardiovascular disease, chronic pain, depression, autoimmune disorders), that provider can issue a Letter of Medical Necessity. The LMN converts what would otherwise be a personal wellness purchase into a potentially qualified medical expense.

The word “potentially” matters. An LMN does not guarantee reimbursement. For FSA and HRA accounts, a third-party administrator employed by the plan sponsor reviews every claim and can reject a sauna purchase outright, regardless of the letter. For HSA accounts, the mechanism is different: the account holder self-directs spending, and the IRS audits after the fact. A non-qualified HSA distribution triggers income tax plus a 20 percent penalty, reported on Form 8889.

The distinction between FSA and HSA is critical, and the brand landing pages we reviewed do not explain it. An FSA claim gets reviewed before you spend the money. An HSA claim gets reviewed (if it gets reviewed at all) after you have already spent it. The risk profiles are fundamentally different.

Three providers, three models

Truemed is the pioneer. Co-founded by Calley Means and Justin Mares, the company launched in 2023 as what TechCrunch described as the “only approved Shopify payment integration” for HSA/FSA checkout. The model is speed and convenience: a consumer answers a health questionnaire at checkout, Truemed’s network of providers reviews it, and 90 percent of LMNs are issued within seven hours. Sauna brand partners include Sun Home, Plunge, HigherDOSE, Sunlighten, and Sauna Republic. The value proposition to brands is conversion lift: make a $5,000 sauna feel like a $3,500 sauna at checkout.

Flex (Flex Technology Co.) takes a broader approach. Founded in 2023 in San Francisco with $18.2 million in funding, Flex integrates with Shopify, Stripe, Shopline, WooCommerce, and custom APIs. The company claims its HSA/FSA checkout option lifts average order value by 50 percent and conversion by 30 percent. Where Flex differs from Truemed is its in-person reimbursement product for gyms, studios, and spas: for a $99 brand setup fee plus $15 per customer LMN, brick-and-mortar wellness businesses can offer HSA/FSA reimbursement at the point of sale. Flex reports that 67 percent of customers using the feature say they would not have made the purchase without it.

SaunaLMN is the sauna-vertical entrant, and its model is deliberately different from both. Where Truemed and Flex provide their own network of prescribing providers, SaunaLMN’s three-step process routes the consumer through a pre-screening questionnaire, generates an Evidence Brief compiling peer-reviewed studies matched to the consumer’s specific condition, and produces a Doctor-Ready Letter that the consumer’s own physician reviews, edits, and signs. The positioning is explicit: SaunaLMN markets itself against “one-click letters from unknown providers,” selling audit-readiness and plan-administrator defensibility rather than checkout speed. The company describes its process as “built for plan administrator review” and HIPAA-aligned.

The difference in philosophy is worth pausing on. Truemed and Flex emphasize speed at checkout; Truemed says 90 percent of its LMNs are issued within seven hours. SaunaLMN is built for defensibility (how well will this LMN hold up if the plan administrator or the IRS asks questions?). Both are valid market positions. The question is which one the regulatory environment will reward.

What the checkout pages leave out

The IRS answered part of that question in March 2024. Alert IR-2024-65 warned consumers to “beware of companies misrepresenting nutrition, wellness and general health expenses as medical care” for FSAs, HSAs, HRAs, and MSAs. The alert stated plainly that a doctor’s note alone is not sufficient. The IRS outlined five tests it applies: the nature and intent of the expense, who recommended it, whether it directly relates to a diagnosed condition, timing relative to the diagnosis, and the “but-for” test (would you have bought this product but for the medical condition?).

Days before the IRS alert, the Washington Post published an investigation by Anahad O’Connor that named Truemed explicitly, described its questionnaire-based process in detail, and quoted co-founder Calley Means at length about the company’s approach. The article listed Truemed’s corporate partners at the time, including CrossFit, Equinox, and Daily Harvest. A subsequent analysis by HSA Talk placed the IRS warning in the context of the Post’s reporting.

There is a second trap that the brand pages we reviewed do not explain. IRS Publication 502 treats a permanently installed home sauna as a capital expense, a medical improvement to the home. The eligible medical deduction must be reduced by any increase in the home’s fair market value resulting from the installation. If a $6,000 sauna installation raises your home value by $3,000, only $3,000 is potentially eligible. Portable units and sauna blankets sidestep this as personal property (not home improvements), but the distinction is not intuitive, and none of the brand checkout pages we reviewed walks consumers through the worksheet.

The practical implication for consumers weighing the investment case for a sauna is that “save 30 to 40 percent” is a ceiling, not a floor. The actual savings depend on a chain of conditions: a qualifying diagnosis, a defensible LMN, a cooperative plan administrator (for FSA) or a clean audit posture (for HSA), and (for installed saunas) a favorable capital-expense calculation.

The policy backdrop

The legislative environment has been a series of near-misses. The PHIT Act of 2025 (H.R.2369, reintroduced March 26, 2025, by Senators Thune and Murphy and Representatives Kelly and Panetta) would add “qualified sports and fitness expenses” to Section 213(d) with a $1,000 individual/$2,000 family cap. But the bill’s language specifies equipment “utilized exclusively for...physical activity,” which likely excludes saunas (passive heat exposure is not physical activity under most legal definitions).

A separate $500/$1,000 physical-activity HSA provision made it into the House reconciliation bill but was excluded by the Senate. The reconciliation bill signed July 4, 2025, expanded HSA plan eligibility but dropped the fitness provision entirely. The Kaiser Family Foundation’s tracker confirms: the broader HSA access provisions survived, the fitness carve-out did not.

The most interesting variable is not in Congress. Truemed co-founder Calley Means has divested from the company and now serves as a senior adviser at HHS under Robert F. Kennedy Jr.’s Make America Healthy Again initiative. NOTUS reported in December 2025 that HHS could influence Treasury and IRS interpretation of what constitutes “medical care” under 213(d). A broader reading of preventive care would not change the LMN requirement, but it could shift the enforcement posture. Whether that influence materializes, and whether it survives administrative transitions, is an open question.

For operators and retailers watching this space, the credibility of health claims in sauna marketing is already under scrutiny. Adding a tax-benefit claim on top of a health-benefit claim compounds the reputational risk if either one does not hold up.

What operators and consumers should know

The HSA/FSA pathway for saunas is real, growing, and (for the right consumer with the right medical documentation) genuinely valuable. Pre-tax dollars represent a meaningful price reduction for purchases that often run $3,000 to $8,000 at the consumer level. The three LMN providers have built legitimate infrastructure around a real legal mechanism.

But the distance between “might be eligible” and “will be reimbursed without consequences” is longer than the brand checkout pages we reviewed suggest. Consumers should understand whether they are using an FSA (administrator-adjudicated, lower personal risk, but the claim can be denied up front) or an HSA (self-directed, the money flows immediately, but audit risk falls entirely on the account holder). They should know whether their LMN came from a provider who examined their specific medical history or from a questionnaire-driven process optimized for speed. And if they are installing a sauna in their home, they should ask their tax adviser about Publication 502’s capital-expense rule before assuming the full purchase price qualifies.

The clinical evidence base for sauna is real and growing. The research supporting thermal therapies for cardiovascular health, chronic pain, and mood disorders is substantial enough to support a defensible LMN for many consumers. The question is not whether saunas have health benefits. The question is whether the process by which those benefits get translated into a tax deduction is rigorous enough to satisfy the entity reviewing the claim.