Skip to main content
Supplement ScienceSupplementScience

When to Talk to a Doctor or Pharmacist About Supplements

This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Tell your doctor and pharmacist about every supplement you take, and check with them before starting one if you take...

Tell your doctor and pharmacist about every supplement you take, and check with them before starting one if you take prescription medicines, are pregnant or breastfeeding, have a chronic condition, or have surgery coming up. Supplements can interact with drugs and affect medical tests, so your care team needs the full list.

Key Takeaways

  • Tell your doctor and pharmacist about every supplement — many people don't, removing a key safety check.
  • Check before starting if you take prescription medicines, especially blood thinners, antidepressants, or heart/blood-pressure/blood-sugar drugs.
  • Also check first if pregnant or breastfeeding, managing a chronic condition, or facing surgery.
  • Some supplements (like high-dose biotin) can skew lab tests — tell the lab and your provider.
  • Bring the actual bottles or a full list; pharmacists are accessible and great at spotting interactions.

Get the free evidence-based When to Talk to a Doctor or Pharmacist About Supplements guide — delivered in 60 seconds.

No spam. Unsubscribe anytime.

Why your care team needs to know

Supplements aren't separate from the rest of your health. They can change how medicines work, alter lab results, and matter before procedures — but providers can only account for what they know about. Surveys consistently show many people don't mention supplements to their clinicians, which removes an important safety check [1][3].

When to check *before* you start

Talk to a doctor or pharmacist first if you:

  • Take prescription or regular over-the-counter medicines — especially [blood thinners](/learn/supplements-and-blood-thinners), antidepressants, and medicines for the heart, blood pressure, or blood sugar. Supplements can increase or decrease a drug's effect [1].
  • Are pregnant or breastfeeding — many supplements are untested in these situations (see [supplements during pregnancy](/learn/supplements-during-pregnancy)).
  • Have a chronic condition — for example reduced [kidney](/learn/supplements-and-kidney-health) or liver function, where some supplements can accumulate or cause harm.
  • Have surgery or a procedure coming up — some supplements affect bleeding or anesthesia (see [stopping before surgery](/learn/when-to-stop-a-supplement-before-surgery)).
  • Are choosing supplements for a child or an older adult on several medicines.

Supplements can skew lab tests

Some supplements change test results — high-dose biotin is a well-known example that can distort certain blood tests. Tell the lab and your provider what you take (see lab-test interference) [2].

How to have the conversation

  • Bring everything — the actual bottles or a written list, including powders, gummies, and 'functional' drinks.
  • Use your pharmacist — they're highly accessible and excellent at spotting interactions, no appointment needed.
  • Don't expect judgment — the goal is safety, not permission. Be honest about doses and how long you've taken something.
  • Report problems — if a supplement caused a reaction, tell your provider and the FDA (see [reporting a supplement problem](/learn/report-supplement-adverse-event)).

Bottom line

A two-minute conversation with a pharmacist can catch an interaction you'd never see coming. When in doubt, ask before you start.

Frequently Asked Questions

Do I really need to tell my doctor about supplements?

Yes. Supplements can interact with medicines and affect lab results, but your care team can only account for what they know about. Many people leave supplements off their medication list, which removes an important safety check, so share the full list including 'natural' products.

When should I check before starting a supplement?

Before starting one if you take prescription medicines, are pregnant or breastfeeding, manage a chronic condition such as reduced kidney or liver function, or have surgery coming up. The same applies when choosing supplements for a child or an older adult on several medicines.

Can I ask a pharmacist instead of a doctor?

Absolutely. Pharmacists are highly accessible, need no appointment, and are excellent at spotting supplement-drug interactions. Bringing your bottles or a written list to the pharmacy counter is one of the easiest ways to catch a problem before it happens.

Why would a supplement affect my blood tests?

Certain supplements interfere with lab measurements. High-dose biotin is a well-known example that can distort some blood tests, potentially leading to wrong results. Telling the lab and your provider what you take helps them interpret results correctly or pause a supplement before testing.

References

  1. National Center for Complementary and Integrative Health (2026). How Medications and Supplements Can Interact. U.S. National Institutes of Health.
  2. U.S. National Library of Medicine, MedlinePlus (2025). Dietary Supplements. MedlinePlus (U.S. National Library of Medicine).
  3. National Institutes of Health, Office of Dietary Supplements (2023). Dietary Supplements: What You Need to Know. NIH Office of Dietary Supplements.