The 5 Supplements Physicians Actually Take (and 3 to Skip)

The global supplement industry generates over $170 billion annually. A substantial portion of that revenue is driven by aggressive marketing, celebrity endorsements, and a regulatory landscape that allows almost any health claim with minimal evidence.

Physicians are not immune to supplements — but we apply a different filter. We ask: what does the peer-reviewed evidence actually show? What is the quality of that evidence? And what is the risk/benefit ratio at typical doses?

Here's my honest assessment after decades of clinical practice and reviewing the literature.

The 5 With Genuine Evidence

1. Vitamin D3 (with K2)

Vitamin D deficiency is endemic — estimated 40% of American adults are deficient. Deficiency is linked to increased risk of bone fracture, immune dysfunction, cardiovascular disease, and all-cause mortality. The evidence for supplementation in deficient individuals is robust. I recommend testing your 25-OH vitamin D level first — targeting 40–60 ng/mL — then supplementing accordingly. K2 (MK-7 form) is co-supplemented because it directs calcium to bone rather than arterial walls.

2. Magnesium Glycinate

Magnesium is a cofactor in over 300 enzymatic reactions. Deficiency (common in Americans eating processed food diets) contributes to muscle cramps, poor sleep quality, hypertension, and insulin resistance. The glycinate form is the best tolerated and most bioavailable — it doesn't cause the diarrhea of magnesium oxide or citrate at higher doses. 200–400mg nightly is a reasonable starting point for most adults.

3. Omega-3 Fatty Acids (EPA/DHA)

The evidence is mixed but leans positive at higher doses. The REDUCE-IT trial showed that high-dose EPA (icosapentaenoic acid, 4g/day as Vascepa) reduced major cardiovascular events by 25% in high-risk patients with elevated triglycerides. Over-the-counter fish oil at typical doses (1g/day) is less compelling for cardiovascular outcomes — but has good evidence for triglyceride reduction and modest anti-inflammatory effects. I recommend 2g/day EPA+DHA minimum if using for cardiovascular health.

4. Creatine Monohydrate

This may surprise you — creatine is associated with bodybuilders, not doctors. But the evidence base is exceptional. It's one of the most studied supplements in existence. Beyond athletic performance, creatine has shown benefits for preserving muscle mass with aging (sarcopenia prevention), cognitive function, and depression. At 3–5g/day, it's remarkably safe. I take it daily.

5. Berberine

Berberine activates AMPK — the same pathway activated by metformin — and has demonstrated meaningful blood glucose-lowering effects in multiple RCTs. For people with pre-diabetes or insulin resistance who are not yet on prescription medication (or as an adjunct), berberine 500mg 2–3x daily before meals is worth discussing with your physician. It's been called "nature's metformin," and while that's marketing-speak, the analogy isn't entirely wrong.

3 Popular Supplements to Skip (or Question Carefully)

1. Collagen Supplements

Collagen peptides are hydrolyzed into amino acids during digestion — they don't travel intact to your skin, joints, or tendons. Some studies show modest benefits in skin hydration and joint pain, but the evidence is industry-funded and weak. If you want to support collagen synthesis, Vitamin C and adequate protein are more reliably effective.

2. Detox/Cleanse Products

Your liver and kidneys are the most sophisticated detoxification systems known to medicine. No supplement does what they do. "Detox" products are, to be blunt, marketing theater. Save the money.

3. Testosterone Boosters (OTC)

Ashwagandha has modest evidence for stress reduction and possibly minor testosterone support. Beyond that, the OTC "T-booster" category is largely ineffective. If you have symptoms of low testosterone, get a serum testosterone level measured. If it's genuinely low, the conversation about treatment is with your physician — not a supplement company.

Supplement Quality Matters Enormously

The supplement industry is regulated differently than pharmaceuticals. A supplement can contain more, less, or different ingredients than labeled — with no pre-market FDA approval required. I only recommend supplements that are third-party tested. Look for NSF Certified for Sport, USP Verified, or Informed Sport certification marks.