The Supplement Truth: What's Worth Taking (And What Isn't)

A five-supplement reality check, by evidence tier.

Walk into any pharmacy and you'll see 400 bottles. Walk out an hour later and you'll have spent $200 and you still won't know what to take.

I'm going to save you the hour.

The supplement industry in the United States is $50 billion a year. The actual number of supplements with strong human evidence for healthy adults is closer to five. Everything else is either food-first territory, test-first territory, or marketing.

Here's the honest map.

The principle

Three rules govern every supplement decision worth making:

1. Food first. If you can get it from food, get it from food. Real food has co-factors, fiber, and absorption profiles that pills never match.
2. Test first. Vitamin D, B12, iron, ferritin, A1c — get the labs before you supplement. Guessing leads to either expensive urine or genuine harm. High-dose vitamin D, for example, can become toxic. Iron without a real deficiency can drive inflammation.
3. Clinician first. Pregnant, breastfeeding, immunocompromised, on blood thinners, kidney or liver disease, or a chronic condition? Every supplement decision goes through your doctor, not through this newsletter or any internet headline.

If you can hold those three rules, the rest of the list is short.

The science, simplified — by tier

Tier 1: Well-evidenced for most healthy adults, after food-first effort.

• Creatine monohydrate (3-5g daily). Originally a strength supplement; now also one of the best-evidenced supports for cognition in aging adults and women, plus muscle preservation during dieting. Cheap, safe for almost everyone with normal kidney function, easy to dose.
• Vitamin D, IF your labs are low. About 35% of US adults are deficient. Test first; supplement based on the gap, not based on guessing. Pair with K2 when supplementing.
• Omega-3 (EPA/DHA), if you don't eat 2-3 servings of fatty fish a week. 1-2g of combined EPA+DHA daily. Watch for bleeding risk if on anticoagulants.

Tier 2: Useful in specific situations, ask your clinician.

• Magnesium glycinate for sleep tension or muscle cramps. Magnesium citrate for stubborn constipation. Avoid if kidney disease.
• Psyllium fiber if your dietary fiber is low — the most clinically validated soluble-fiber supplement. Drink it with water. Space it from medications.
• Protein powder as a bridge, not a base. If you can't hit 100g protein from food, a whey or plant blend closes the gap. Third-party tested (USP, NSF, or Informed Choice).

Tier 3: Test first; don't guess.

• B12 if you're vegan, over 60, taking metformin, or taking a PPI long-term. Otherwise food.
• Iron ONLY if labs show low ferritin. Iron without deficiency is harmful, not helpful.

Tier 4 — Skip entirely (or close to it).

• Multivitamins. A 2024 Annals of Internal Medicine analysis of 400,000+ adults found no mortality benefit. They're not harmful, but the dollars are better spent on real food.
• Most "anti-aging" or "longevity" stacks. Resveratrol, NMN, NR — promising lab work, weak human data, expensive. Wait for the trials.
• Testosterone "boosters." Almost none have evidence. The ones that do have lab-grade compounds shouldn't be sold OTC.
• Detox teas, fat burners, hormone-balancing stacks. Often contain undisclosed stimulants or anabolic agents. The FDA has issued repeated warnings.
• Peptides sold online (BPC-157, TB-500, MOTs-C, CJC-1295, etc.). The FDA has flagged safety concerns for compounded versions. These are medical decisions, not supplements.

What to do this week

1. Audit what you're already taking. Lay every bottle on the counter. For each one, ask: "What problem does this solve? Where is the evidence?" If you can't answer, that bottle goes back in the cabinet or in the trash.
2. Ask your clinician about a basic lab panel if you haven't had one in 12+ months. Vitamin D, B12, ferritin, A1c, basic metabolic panel, lipid panel. That's the foundation for any supplement decision.
3. Pick one Tier 1 supplement and add it. Creatine if you're training. Omega-3 if you don't eat fish. Vitamin D if your labs are low. One. Not three.

The reason most supplement protocols fail is they're sold as "the stack." Five bottles, $200/month, and within 90 days the user has stopped taking four of them and isn't sure which one was supposed to do what. One supplement at a time, four weeks each, journaled. That's the only way to know what's actually moving the needle for you.

Educational only. Not medical advice. Supplements can interact with medications and medical conditions. Talk with a qualified clinician — especially if you're pregnant, breastfeeding, immunocompromised, on blood thinners, or managing a chronic condition.