Vitamin and mineral supplements: what the evidence says

Pantothenic acid deficiency essentially does not occur in people who eat food, and supplementing it has no demonstrated benefit.

Vitamin K1 (phylloquinone) is essential for blood clotting, and dietary deficiency is rare outside newborns and fat malabsorption.

Selenium was the great cancer-prevention hope of the 1990s and large randomised trials comprehensively killed it.

Copper deficiency is real and can be neurologically devastating, but it is almost always secondary to something else — bariatric surgery, malabsorption, or too much zinc.

Manganese is an essential cofactor, but dietary deficiency in humans has essentially never been documented outside experimental depletion — while manganese excess is a well-characterised neurotoxic syndrome.

Boron plausibly does something — depletion-repletion studies show it shifts calcium, magnesium and sex hormone markers.

Kelp is a real source of iodine, but an unreliable one — content varies enormously between batches and label accuracy is poor.

Molybdenum is genuinely essential — it is the cofactor for sulfite oxidase and two other enzymes — but dietary deficiency essentially does not occur outside long-term parenteral nutrition.

P5P is the active coenzyme form of vitamin B6, but oral P5P is stripped of its phosphate in the gut before absorption and re-phosphorylated in the liver — so for almost everyone it behaves like ordinary pyridoxine at three times the price.

Some liposomal formulations do produce modestly higher plasma vitamin C than the same dose of plain ascorbic acid, but the trials are small, mostly industry-funded and inconsistent — and no study shows a clinical outcome that ordinary vitamin C cannot deliver.

Ester-C is calcium ascorbate with trace vitamin C metabolites, sold on claims of superior absorption and 24-hour retention.

Sodium ascorbate is biologically identical to ascorbic acid once absorbed.

MK-4 is a licensed osteoporosis drug in Japan at 45 mg/day — but that is pharmacology, not supplementation.

Vitamin C from acerola, camu camu or citrus blends is the same ascorbic acid molecule your body absorbs through the same transporter.

A perfectly reasonable, well-absorbed organic magnesium salt sold on a story — that malic acid feeds the Krebs cycle and therefore fights fatigue and fibromyalgia pain — which no blinded trial has actually supported.

The claim that picolinate is the best-absorbed zinc comes from a single 15-person crossover trial published in 1987 and never replicated in nearly four decades.

Mostly a branded ferric pyrophosphate wrapped in a phospholipid and sucrester matrix, sold at several times the price of ferrous sulfate.

Chemically it is calcium carbonate with trace minerals, sold on infomercial claims about curing hundreds of diseases that produced US regulatory enforcement rather than clinical trials.

Plant-sourced calcium from red marine algae (Lithothamnion, sold as Aquamin and similar), marketed as more absorbable and better for bone than calcium carbonate.

Concentrated seawater or Great Salt Lake brine sold as '72+ ionic trace minerals'.

Para-aminobenzoic acid was once marketed as "vitamin Bx" — it is not a vitamin for humans, and the grey-hair and vitiligo claims that sell it come from uncontrolled 1940s reports.

Micronutrient supplementation clearly helps children who are actually deficient.

One of the two coenzyme forms of vitamin B12, required by a mitochondrial enzyme.

A fat-soluble thiamine derivative that raises blood thiamine much more than plain thiamine.

Zinc bound to methionine, marketed as the best-absorbed zinc.

Ground bone-matrix calcium that also contains collagen and trace minerals.

Calcium carbonate ground from oyster shell.

Iron in the heme form from animal blood, sold as better absorbed and gentler.

Broad mineral formulas sold without the vitamins.

Flavonoids from citrus peel, sold since the 1930s as a vitamin C companion for capillaries.

Niacin-bound chromium sold for blood sugar and cravings.

A concentrated iodine-iodide solution that delivers milligram doses, far beyond nutritional needs.

The classic three-mineral bone tablet.

A trace mineral in a chelated form, marketed for bones and hormones.