Casein Protein
How these lines are chosen
Among 8 products and 8 retailer listings we track; Amazon and Walmart are not included. A month is thirty doses of 25g, priced the same way as the figure beside it. It is worked out before that figure is rounded, so it can differ from thirty times it by a few cents. It is not thirty servings where a serving holds more or less than 25g. “Delivery known” ranks only products whose retailer publishes a delivery rate. A cheaper product whose rate is not published gets a line of its own, or is in the full list below.
Why this pick, and what came closest
Not a score, no weightings to argue with. It is the cheapest per delivered dose among products whose delivery cost we know and that clear four factual bars:
- a certification we confirmed applies to this package, naming it where the certifier names packages
- no recall, warning letter or failed test in the sources we checked
- a current price, not a last known one
- no more than a year's supply at the label's serving
It is provisional. It is the best answer among the products, retailers and sources we have checked, and that set is still narrow.
Casein powders, not whey and casein blends. Prices here are figured on the protein the brand's panel states per serving, not per scoop or per tub.
Prices checked daily. Every figure links to its source. Where the data comes from
- 4 named at the exact package by a certifier
- 2 certified with no package named
- 2 in no database we searched
| Product | Delivery | |||||
|---|---|---|---|---|---|---|
NUTR | $1.09 $32.75/mo | D · None located Could not locate independent data | $82.97 checked Nov 13, 2026 | free | 76 76 days at 1/day | Buy Nutricost (direct) |
BULK | $1.27 $38.15/mo + delivery | A · NSF Certified for Sport Independently certified | $41.97 checked Nov 13, 2026 | not free $17.04 short | 33 33 days at 1/day | Buy BulkSupplements.com |
NUTR | $1.43 $42.97/mo + delivery | D · None located Could not locate independent data | $42.97 checked Nov 13, 2026 | not free $16.04 short | 30 30 days at 1/day | Buy Nutricost (direct) |
ON Optimum Nutrition Gold Standard 100% Casein, Chocolate Supreme (3.97 lb) · our pick powder · 24g per serving · 1.04 per dose Also contains, not counted in the price per dose: magnesium 85 mg and zinc 11 mg | $1.92 $57.48/mo | B · Informed Choice Independently tested | $97.49 checked Nov 13, 2026 | free | 53 = 51 doses 51 days at 1/day | Buy Optimum Nutrition (direct) |
BULK | $1.94 $58.18/mo + delivery | A · NSF Certified for Sport Independently certified | $32.97 checked Nov 13, 2026 | not free $26.04 short | 17 17 days at 1/day | Buy BulkSupplements.com |
ON Optimum Nutrition Gold Standard 100% Casein, Chocolate Supreme (1.87 lb) powder · 24g per serving · 1.04 per dose Also contains, not counted in the price per dose: magnesium 85 mg and zinc 11 mg | $2.40 $71.86/mo | B · Informed Choice Independently tested | $57.49 checked Nov 13, 2026 | $5.99 | 25 = 24 doses 24 days at 1/day | Buy Optimum Nutrition (direct) |
BULK | $3.12 $93.64/mo + delivery | A · NSF Certified for Sport Independently certified | $24.97 checked Nov 13, 2026 | not free $34.04 short | 8 8 days at 1/day | Buy BulkSupplements.com |
BULK | $7.32 $219.70/mo + delivery | A · NSF Certified for Sport Independently certified | $21.97 checked Nov 13, 2026 | not free $37.04 short | 3 3 days at 1/day | Buy BulkSupplements.com |
Common questions
About these numbers
What “per dose” means here: 25g protein
The ISSN position stand on protein and exercise gives a per-serving dose of 0.25 g/kg of body weight, or an absolute 20-40 g, to maximize muscle protein synthesis. 25 g is a round number inside that stated range, chosen so products with different scoop sizes can be priced against each other. It is a yardstick for comparing prices, not a recommended intake, and it cannot change which product is cheapest: it scales every row in the category by the same number.
Compared on grams of protein per serving, as printed in the Nutrition Facts or Supplement Facts panel. The scoop is not the basis: scoops differ from one brand to the next and carry different amounts of protein, so per-scoop and per-tub prices are not comparable. Whey, casein and plant proteins share this basis and are compared in their own categories.
Where the data comes from
- Where a servings-per-container figure was not read from the package's own panel, the product page says how it was worked out.
- Amazon and Walmart are not included, so “cheapest” means cheapest among the retailers we track.
- Prices go stale. Each product page shows when its price was last checked, and a price older than the retailer allows us to cache is marked as a last known price wherever it appears.
- iHerb prices cannot be refreshed automatically. iHerb has not given us access to its price data, so those prices are marked stale until they are re-read. Each retailer offer carries its own check date.
How we make money
No Buy button on this page earns us anything. Where a link elsewhere on the site can, it says so beside the link.
Commission will play no part in what we list, how it ranks, or which link we send you to. The Buy button points at the lowest price we have recorded even when that retailer pays us nothing.