Every December, the same ritual plays out in pharmacy aisles across the country. Millions of Americans, staring down a hard deadline, load up their carts with whatever qualifies: extra bandages, a third bottle of sunscreen, cold medicine they don't need yet. It's not because they want these things — it's because they're about to lose the money if they don't spend it.
This scramble is almost entirely avoidable, and most people don't realize it.
The Size of the Problem
Roughly 62 million Americans are covered by a Health Savings Account (HSA). Flexible Spending Accounts (FSAs) are harder to pin to a single national number, but employer access is widespread — 47% of private-industry workers and 72% of state and local government workers had access to an FSA in 2025, according to federal labor data. HSAs roll over year to year, but FSAs typically operate on a strict "use it or lose it" calendar — unspent funds vanish on December 31st unless your employer offers a small grace period.
That deadline pressure creates a predictable, wasteful pattern: instead of researching what's actually eligible, account holders panic-buy low-value over-the-counter items just to zero out the balance. Meanwhile, higher-value products — the kind that could genuinely improve someone's daily life — often get overlooked entirely, simply because most people don't know they qualify.
The Real Unlock: A Letter of Medical Necessity
Here's what most HSA/FSA holders don't know: eligibility isn't limited to a fixed list of OTC products. Under IRS Publication 502 and Internal Revenue Code §213(d)(1)(A), any product or service that treats, mitigates, or prevents a diagnosed medical condition can qualify as a reimbursable medical expense — if it's supported by a Letter of Medical Necessity (LMN) from a treating physician.
That single document is the master key. It's what transforms a "dual-use" product — something that could be seen as general wellness or medical treatment, depending on context — into a fully qualified expense. Adaptive kitchen tools for arthritis. Ergonomic aids for tremors. Recovery equipment for joint impairment. These aren't gimmicks; they're legitimate medical expenses hiding in plain sight, unlocked by three sentences from a doctor.
What Separates an LMN That Gets Approved From One That Gets Denied
Not all letters are created equal. Administrators (HealthEquity, WEX, Optum, and others) are looking for specific markers of legitimacy, and vague or generic letters are the ones that get kicked back or flagged for audit. A strong LMN includes:
- Explicit legal citations — direct reference to IRC §213(d) and IRS Publication 502, not just a general claim of "medical necessity"
- Site-specific ICD-10 codes — for example, M19.041 (osteoarthritis, right hand) or M18.11 (osteoarthritis, first carpometacarpal joint) rather than a vague, unspecified code like M19.90
- A clear duration of need — 12 months or lifetime, explicitly stated rather than left blank
- Verifiable physician credentials — a real NPI number and state license, not a placeholder
- Documented functional limitations — grip strength deficits, failed conservative alternatives, or other objective clinical detail that shows why this specific product is necessary
A letter with all five of these elements is dramatically more likely to survive both the initial reimbursement request and, if it ever comes up, an IRS audit down the line.
De-Risking Before You Spend
The smartest move before making a purchase is to use your account administrator's optional pre-verification feature. Most major HSA/FSA administrators allow you to submit your LMN for a quick eligibility check before you spend out of pocket, so you're not gambling on reimbursement after the fact. It's a free safety net that almost nobody uses simply because they don't know it exists.
Why This Beats the December OTC Scramble
Compare the two paths:
Path A: Wait until December, panic, buy random eligible OTC items you don't really need, in amounts you don't need, just to zero out your balance.
Path B: Identify a real, diagnosed condition earlier in the year, get a properly documented LMN from your own physician, pre-verify it with your administrator, and invest those same dollars in a product that actually improves your daily function long-term.
Path B isn't just smarter financially — it's a fundamentally better use of a benefit that was designed to support real health needs, not stopgap purchases made under deadline pressure.
The Bottom Line
If you have a chronic condition — arthritis, tremors, joint pain, limited grip strength, or similar — don't wait for December to figure out what your HSA or FSA can do for you. Talk to your physician about a Letter of Medical Necessity for products that genuinely support your condition. It's the difference between spending your pre-tax dollars reactively and investing them intentionally.
Note: Eligibility is ultimately determined by your plan administrator. Products like these are best described as "HSA/FSA eligible with a Letter of Medical Necessity" — always verify with your provider before purchasing.
We're Looking for Beta Testers
We built a free tool that generates properly formatted medical necessity documentation — including site-specific ICD-10 codes, legal citations, and the documentation standards outlined above — designed for your own treating physician to review and sign. No health data is stored; it's session-based and private by design.
Whether you're looking to use HSA/FSA pre-tax dollars, or you're pursuing Medicare, Medicaid, or private insurance reimbursement, the tool generates the right documentation for your specific pathway.
We're looking for people living with osteoarthritis, hand/wrist conditions, or grip-related limitations to try it out — regardless of which reimbursement path applies to you. Generate your letter, bring it to your physician, submit it through your relevant channel (HSA/FSA administrator or insurance/DME process), and let us know how it went. As a thank-you, testers receive a free NULU cutting glove.
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While this article focuses on HSA/FSA pre-tax accounts, our generator is also built to create documentation for commercial insurance, Medicare, Medicaid, and other DME/E1399 claims. If you're pursuing one of those coverage options, the tool will format your documentation accordingly.
