VitaminDB Data Study · July 2026
The biggest supplement discount is the bottle size
We compared the cost per serving of the large bottle (180+ servings) against the small bottle (under 60) of the same nutrient across 27 nutrients. The big bottle costs a median 81% less per serving — and up to 96% less for Prenatal Vitamin, where it runs $0.042 per serving versus $1.07 in the small size. No coupon comes close.
The key finding
People hunt for coupons and subscribe-and-save discounts worth 5–15%. Meanwhile the single biggest lever in supplement value is sitting in plain sight: pack size. Across 27 nutrients the large bottle costs a median 81% less per serving than the small one — for Prenatal Vitamin it’s 96%. Whole-catalog, the median large-bottle serving is $0.067 versus $0.48 for small bottles.
The caveat is real but simple: buy the biggest size you’ll actually finish before it expires, and for something you’re only trialing, a small bottle can still be the smarter first buy. Otherwise, size up — it beats every coupon.
Big-bottle saving by nutrient
| Nutrient | Small ($/serving) | Large ($/serving) | Big bottle saves | Sample (small / large) |
|---|---|---|---|---|
| Prenatal Vitamin | $1.07 | $0.042 | 96% | 3 / 5 * |
| Vitamin B5 | $1.59 | $0.080 | 95% | 3 / 11 * |
| Vitamin B9 | $0.60 | $0.037 | 94% | 10 / 51 |
| Collagen Peptides | $0.93 | $0.077 | 92% | 28 / 7 |
| Iron Bisglycinate | $0.68 | $0.064 | 90% | 6 / 6 |
| B-Complex | $0.70 | $0.079 | 89% | 3 / 18 * |
| Methylcobalamin | $0.52 | $0.062 | 88% | 6 / 17 |
| Vitamin D3 | $0.47 | $0.054 | 88% | 25 / 125 |
| Calcium | $0.56 | $0.075 | 87% | 6 / 25 |
| Magnesium | $0.56 | $0.080 | 86% | 11 / 28 |
| Vitamin B6 | $0.37 | $0.057 | 84% | 12 / 35 |
| Vitamin K2 | $0.40 | $0.074 | 82% | 9 / 20 |
| Omega-3 EPA/DHA | $0.56 | $0.11 | 81% | 5 / 11 |
| Vitamin B12 | $0.35 | $0.066 | 81% | 21 / 51 |
| Vitamin C | $0.45 | $0.096 | 79% | 16 / 39 |
| Vitamin B7 | $0.24 | $0.055 | 77% | 8 / 23 |
| Ginkgo Biloba | $0.33 | $0.078 | 76% | 7 / 6 |
| Vitamin B3 | $0.29 | $0.073 | 74% | 6 / 42 |
| Vitamin E | $0.26 | $0.069 | 74% | 7 / 7 |
| Melatonin | $0.22 | $0.060 | 73% | 12 / 25 |
| Vitamin B2 | $0.27 | $0.077 | 72% | 4 / 9 * |
| Zinc | $0.28 | $0.079 | 72% | 14 / 11 |
| L-Carnitine | $0.44 | $0.13 | 70% | 3 / 3 * |
| Inositol | $0.19 | $0.077 | 60% | 4 / 10 * |
| CoQ10 | $0.43 | $0.17 | 59% | 18 / 5 |
| Milk Thistle | $0.25 | $0.11 | 56% | 4 / 8 * |
| Alpha-Lipoic Acid | $0.23 | $0.11 | 53% | 5 / 7 |
“Big bottle saves” = 1 − large median ÷ small median cost per serving. Small = under 60 servings, large = over 180. Live from the curated Amazon US catalog. Updated July 2026. * Small sample (<5 products) on at least one side — read these rows as directional.
How we calculated it
Cost per serving = price ÷ servings per container. For each nutrient we take the median cost per serving of its small bottles (under 60 servings) and its large bottles (over 180), comparing small vitamin-C against large vitamin-C — never one nutrient against another.
The saving = 1 − the large median ÷ the small median. A row appears only when a nutrient has at least 3 products on each side; rows with fewer than 5 on either side are flagged as directional above. Prices and serving counts come from product labels in our live catalog.
This is a value comparison, not medical or dosing advice. Buy a size you’ll finish before expiry — the figures show what the market charges per serving, nothing about how much of a supplement you should take.
See the cheapest size of each supplement
VitaminDB ranks every product by real cost-per-dose, so the big-bottle saving is never hidden. Compare Prenatal Vitamin, Vitamin B5, Vitamin B9, or browse all nutrients
For journalists & researchers — free to cite
These findings are free to quote with a link back to this page. Key data points (as of July 2026):
- The large bottle (180+ servings) of a supplement costs a median 81% less per serving than the small bottle (under 60) — up to 96% for Prenatal Vitamin ($0.042 vs $1.07 per serving).
- Whole-catalog, the median large-bottle serving is $0.067 versus $0.48 for small bottles, across 692 large and 317 small products.
- Based on 27 nutrients with at least 3 products per size tier; compared per serving (price ÷ servings) within each nutrient. This measures what the market charges, not medical benefit.
Questions, interviews, or a custom data cut? Email [email protected].
Frequently asked questions
Are bigger bottles of vitamins cheaper per serving?
Almost always, and by a lot. Across 27 nutrients with enough products to compare, the large bottle (180+ servings) costs a median 81% less per serving than the small bottle (under 60). Whole-catalog, the median large-bottle serving is $0.067 versus $0.48 for small bottles.
Which supplement saves the most by buying the big bottle?
Prenatal Vitamin: the large bottle costs $0.042 per serving versus $1.07 for the small one — a 96% saving.
Is buying the biggest bottle always the best value?
Per serving, yes for essentially every nutrient we track — even the smallest gap (Alpha-Lipoic Acid) still saves 53%. Two honest caveats: buy a size you'll finish before its expiry, and for a nutrient you're only trialing, a small bottle can be the smarter first buy even at a higher per-serving cost.
How is the bottle-size saving calculated?
For each nutrient we compute cost per serving = price ÷ servings per container, then take the median for small bottles (under 60 servings) and large bottles (over 180). The saving is 1 − large median ÷ small median. Only nutrients with at least 3 products on each side are compared, recomputed from the live Amazon US catalog.