The Same Supplement Can Cost 11× More Per Day (2026 Data)
Key finding: Across 115 products in 29 supplement categories, the cost to take the same supplement every day varies up to 10.9× (Curcumin) depending on brand and form. And in 48% of categories (14 of 29), the cheapest product by sticker price is not the cheapest per day — because servings-per-container and dose-per-serving swing the real cost far more than the price on the bottle.
All figures are computed from our open dataset (CC BY 4.0), last price-verified July 8, 2026. Methodology below. If you cite these numbers, please link this page.
Cost-per-day spread, by supplement
For each category we take the lowest and highest cost per clinically-effective daily dose among the products we track, normalized to the active-ingredient amount studied in trials (not per pill, not per serving).
| Supplement | Cheapest / day | Most expensive / day | Spread |
|---|---|---|---|
| Curcumin | $0.11 | $1.20 | 10.9× |
| Creatine | $0.20 | $1.67 | 8.3× |
| Vitamin K2 | $0.07 | $0.57 | 8.1× |
| Vitamin C | $0.07 | $0.51 | 7.3× |
| Vitamin D3 | $0.05 | $0.36 | 7.2× |
| Ashwagandha | $0.11 | $0.73 | 6.6× |
| Omega-3 | $0.39 | $2.55 | 6.5× |
| Probiotics | $0.31 | $2.00 | 6.5× |
| L-theanine | $0.14 | $0.77 | 5.5× |
| Magnesium glycinate | $0.18 | $0.87 | 4.8× |
| Biotin | $0.10 | $0.47 | 4.7× |
| Vitamin B12 | $0.10 | $0.40 | 4.0× |
A concrete example: magnesium glycinate
The same form of magnesium, at the same elemental dose, runs from $0.18/day (BulkSupplements.com) to $0.87/day (Thorne) — a 4.8× gap. Over a year that is the difference between about $66 and $318 for the identical active ingredient.
Why the cheapest bottle usually isn't the cheapest supplement
Shoppers optimize for the number on the shelf, which is the wrong number. Two bottles at the same sticker price can differ 3–5× in real cost once you account for how many days each one lasts and how much active ingredient each dose delivers. In our data this happens in 48% of categories.
Methodology
- Cost per effective daily dose = price ÷ servings per container, normalized to the clinically-studied dose of the active ingredient.
- Prices are the current Amazon Buy Box price, refreshed via the Amazon Product Advertising API and last verified July 8, 2026.
- Ingredient doses and forms are from the NIH Dietary Supplement Label Database; clinical doses from PubMed. Full method on our methodology page.
- Reproducible from the public dataset (115 products, 29 categories, CC BY 4.0).