How prices are computed
Sticker prices hide the real cost of a supplement. A cheap tub with a small scoop count is often the expensive option. This site normalizes every Amazon listing into the unit that actually matters for its category, then ranks by it — the same idea as diskprices.com, applied to supplements.
The price column
Everything is quoted per amount of active ingredient, never per serving — serving sizes are a marketing choice. The unit matches how the substance is dosed:
| Unit | Used for | Example |
|---|---|---|
| $ / g | Protein, creatine, magnesium, zinc, NAC, taurine, collagen, omega-3 (EPA+DHA)… | $0.024 per g creatine |
| $ / mg | µg/mg-dosed actives: melatonin, B12, folate, biotin, K2, selenium, iodine, boron | $0.07 per mg folate |
| $ / 1,000 IU | Vitamin D | $0.010 per 1,000 IU |
| $ / billion CFU | Probiotics | $0.012 per billion CFU |
| $ / serving | Multi-ingredient stacks only (multivitamin, electrolytes, greens, B-complex, BCAA/EAA) | $1.10 per serving |
In the “All” view every product is shown per gram of active so one column stays comparable; the Dose column shows the per-serving amount (mg, IU, CFU) the label claims.
Where the numbers come from
Sizes, counts, doses and servings are parsed from the listing itself (title, size and feature bullets): “5 lb, 74 servings, 24g protein” → 2.27 kg, 1,776 g protein, price ÷ 1,776. Multipacks (“2 × 500g”), European number formats (“2,27 kg”, “1.000 mg”), IU→µg conversion for vitamin D, and per-tablet vs. per-serving doses are handled.
When a listing doesn’t state something, we fall back to typical values for the category — a 30 g scoop for whey, ~78% protein for a concentrate, 90% for an isolate, 2 softgels per serving for fish oil, ~30% omega-3 in unspecified fish oil. Every number that relies on such a fallback is marked ~ and can be filtered out entirely with “Hide estimates”.
Stacks
Multi-ingredient products (multivitamins, electrolytes, greens) show an expandable ingredient list with per-serving amounts where known. Single-nutrient combos detected in titles (“D3 + K2 + Zinc”) are tagged as small stacks too, so a cheap vitamin D price that’s really a bundle is visible as such.
Pre-workouts are deliberately not listed. Every blend is a different set of ingredients at different doses, so neither price per gram nor price per serving compares like with like. For the one ingredient that would be comparable, see the caffeine category.
Data freshness & countries
Prices come from the Amazon Product Advertising API for each marketplace (currently 10 Amazon countries) and are refreshed on a schedule; the timestamp above the table shows the last sync. Prices and availability can change at any time — what Amazon shows at checkout is what applies. Each country is a separate catalog in its own currency; use the marketplace picker to switch.
Affiliate disclosure
Product links carry an Amazon Associates tag. As an Amazon Associate, this site earns from qualifying purchases, at no extra cost to you. That’s the whole business model — rankings are computed from the numbers alone and are never sponsored.
Not medical advice
This is a price-comparison tool, not health guidance. Doses shown are what manufacturers print on labels. Talk to a medical professional about what (and whether) to supplement.