You can use an HSA to buy supplements only when a medical practitioner has recommended them to treat a specific condition a physician has diagnosed. General-wellness supplements do not qualify, no matter how healthy they are. The rule turns on the reason for the purchase, not the product itself: the same bottle of vitamin D is an eligible expense for someone with a documented deficiency and an ineligible expense for someone taking it to stay healthy.
The IRS Rule in Plain Language
IRS Publication 502 states the standard directly: “You can’t include in medical expenses the cost of nutritional supplements, vitamins, herbal supplements, ‘natural medicines,’ etc., unless they are recommended by a medical practitioner as treatment for a specific medical condition diagnosed by a physician.”1Internal Revenue Service. Publication 502 (2025), Medical and Dental Expenses – Section: Nutritional Supplements
Two things have to be true at once. A physician has diagnosed a specific condition, and a medical practitioner has recommended the supplement as treatment for that condition. Supplements taken to “maintain your ordinary good health” fail the test.2Internal Revenue Service. Publication 502 (2025), Medical and Dental Expenses – Section: What Are Medical Expenses?
Why Over-the-Counter Drugs Follow Different Rules
This is where people get tripped up. The CARES Act of 2020 made over-the-counter medications reimbursable from HSAs without a prescription, so ibuprofen, allergy pills, and cold medicine now go through your HSA card without a second thought.3Internal Revenue Service. IRS Outlines Changes to Health Care Spending Available Under CARES Act Supplements were not included.
The FDA treats them differently, and the tax rules follow. OTC drugs carry a “Drug Facts” label and are regulated as medicines. Dietary supplements carry a “Supplement Facts” label and are regulated as food. The CARES Act loosened the rules for the first category only. Supplements still need the diagnosed-condition-plus-recommendation standard.
What Qualifies and What Doesn’t
These supplements typically qualify when a doctor recommends them for a diagnosed condition:
- Iron supplements prescribed for iron-deficiency anemia confirmed by bloodwork.
- Vitamin D recommended for a documented deficiency, usually after a serum 25-hydroxyvitamin D test shows low levels.
- Calcium recommended to treat or prevent osteoporosis diagnosed through a bone density scan.
- Fiber supplements prescribed as part of treatment for a diagnosed gastrointestinal condition such as irritable bowel syndrome.
- Prenatal vitamins recommended by an OB-GYN during pregnancy. Prenatals are not automatically eligible; they follow the same rule as every other supplement.1Internal Revenue Service. Publication 502 (2025), Medical and Dental Expenses – Section: Nutritional Supplements
These stay ineligible regardless of what your doctor thinks:
- Daily multivitamins taken for general health. No diagnosed deficiency, no eligibility.
- Protein powders and meal replacements, unless they treat a specific disease and cost more than a normal diet would.
- Herbal supplements for wellness. Turmeric, ashwagandha, elderberry, and similar products taken for general well-being don’t qualify.
- Weight-loss supplements for cosmetic reasons. Even with a doctor’s note, weight-loss products qualify only when tied to a specific disease diagnosis such as obesity-related heart disease.
The Doctor’s Letter You’ll Need
The IRS never uses the phrase “Letter of Medical Necessity” in the tax code or its publications. What it requires is proof that a medical practitioner recommended the supplement to treat a specific diagnosed condition.1Internal Revenue Service. Publication 502 (2025), Medical and Dental Expenses – Section: Nutritional Supplements HSA administrators typically ask for a written document proving exactly that, and the industry calls it a Letter of Medical Necessity. The label matters less than the content.
A letter that will hold up should name the specific diagnosed condition (not vague language like “general wellness”), the exact supplement, the dosage, and the expected duration of treatment. “I recommend Patient X take vitamin D” is almost useless. “Patient X has a serum 25(OH)D level of 18 ng/mL, consistent with vitamin D deficiency, and I recommend 2,000 IU of vitamin D3 daily for six months” is what actually works.
Most HSA administrators treat these letters as valid for about 12 months and then want a fresh one. That’s an industry norm, not an IRS rule, so check with yours. Ask for the letter at the same appointment where your doctor makes the diagnosis or reviews your lab results; the connection between supplement and diagnosis is clearest then.
Receipts and How Long to Keep Them
The letter alone isn’t enough. You also need proof of every purchase. The IRS requires records showing that HSA distributions went to qualified medical expenses.4Internal Revenue Service. IRS Audits – Section: How Far Back Can the IRS Go to Audit My Return? You won’t send these with your return, but you need them ready if asked.
Keep the doctor’s letter and an itemized receipt for each purchase showing the date, product name, and amount. A credit card statement reading “CVS $34.99” doesn’t cut it. You need the receipt that says “Nature Made Vitamin D3 2000 IU — $34.99.” The IRS wants to see what you bought, not just where you shopped.
The general statute of limitations for IRS audits is three years after a return is filed.5Office of the Law Revision Counsel. 26 USC 6501 – Limitations on Assessment and Collection Hold your supplement receipts and letters for at least that long. Scanning them into a secure cloud folder or your HSA portal beats saving paper pharmacy receipts, which fade fast. If the IRS suspects fraud, the three-year limit doesn’t apply, so keeping records longer costs nothing.
Paying With the Card vs. Reimbursing Yourself
You have two ways to move HSA money toward a supplement purchase. Use the HSA debit card at checkout, or pay out of pocket and reimburse yourself later.
The card is faster but often fails at supplements. Many retailers use an automated system called IIAS (Inventory Information Approval System) that checks at the register whether a scanned item qualifies for HSA or FSA reimbursement. It works well for bandages and prescription copays. Supplements often aren’t flagged as eligible in the retailer’s inventory database, even when you have a valid doctor’s letter. When that happens, the card gets declined for that item, and you’ll need to fall back to reimbursement.
For reimbursement, pay with your personal card, then log into your HSA provider and submit a claim with the itemized receipt and the doctor’s letter attached. Turnaround varies, but most administrators process straightforward claims within a week or two and deposit funds into your linked bank account. There’s no deadline for submitting a reimbursement claim, which is one of the more powerful HSA features. You can pay for a supplement today and reimburse yourself years from now, as long as the expense was incurred after you opened the HSA and you still have the documentation.
What It Costs If You Get It Wrong
Using HSA money for a supplement that doesn’t meet the standard triggers two hits. The amount is added to your gross income for the year and taxed at your ordinary rate, and you owe an additional 20% tax on top.6Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans – Section: Additional Tax
Spend $500 on ineligible supplements in the 22% bracket, and you owe $110 in regular income tax plus another $100 in penalty tax. That’s $210 in extra costs for $500 of supplements. The math gets worse quickly if you’ve been buying supplements with the HSA card all year without documentation.
The 20% penalty goes away at age 65, or if you become disabled, or upon death of the account holder. After 65, non-qualified distributions still get added to your gross income and taxed at your normal rate, but the extra 20% disappears.7Internal Revenue Service. Publication 969 (2025), Health Savings Accounts and Other Tax-Favored Health Plans – Section: Exceptions At that point the HSA works like a traditional retirement account for anything you spend outside medical care.