A slow-digesting micellar casein with 24 g of protein per scoop for bedtime or long gaps between meals; thick, filling and fairly priced.
Good
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Last reviewed September 29, 2026 by the Nutrition Reviews Editorial Team · How we review
Our verdict
Gold Standard 100% Casein is a dependable, well-priced micellar casein for nighttime or between-meal protein, with good flavor and a filling texture. It lacks the named third-party certification of ON's whey and uses artificial sweeteners, but for most people who want a slow-digesting shake it does the job at a fair price.
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Key ingredients at clinically studied doses, and how strong the evidence is.
Third-party testing and certifications, manufacturing standards, contaminant testing, recall history.
Cost per effective serving compared with category peers.
Taste, mixability, texture and tolerability from aggregated buyer and creator feedback.
Full label disclosure (no proprietary blends), available COAs, honest marketing.
Gold Standard 100% Casein is Optimum Nutrition's slow-release counterpart to its best-selling whey and one of the most widely sold casein powders. A 34 g scoop of Chocolate Supreme provides 24 g of protein from micellar casein, with 120 calories, 4 g of carbohydrate and 1 g of sugar. It also carries notable minerals: 500 mg of calcium (40% DV), 85 mg of magnesium and 11 mg of zinc (100% DV) per scoop.
Casein forms a gel in the stomach and releases amino acids gradually over several hours, which is why it is typically used before bed or during long gaps between meals. Research on pre-sleep protein has mostly used 30 to 40 g servings, so one scoop sits a little below that; a heaping scoop or one and a half scoops gets closer. For overall muscle gain, evidence suggests total daily protein matters more than protein type or timing.
The label is fully disclosed with no proprietary blend. Unlike Gold Standard Whey, this casein is not among the products Optimum Nutrition lists as Informed Choice certified, although the brand describes it as banned-substance tested. It uses both acesulfame potassium and sucralose plus artificial flavor.
Buyers give the Chocolate Supreme tub 4.6 stars across more than 9,000 buyer ratings, often saying it tastes good and keeps them fuller than whey. The thick, pudding-like consistency is polarizing, and reviews split on mixability and texture. At about $1.40 per serving for 53 servings, it is well priced for a micellar casein.
| Key ingredient | Per serving | Why it matters |
|---|---|---|
| Micellar casein Slow-digesting milk protein that releases amino acids over several hours. | 24 g protein | Slow-digesting milk protein that releases amino acids over several hours. |
| Naturally occurring essential amino acids Brand-stated EAA content per serving, from the casein itself. | 9 g | Brand-stated EAA content per serving, from the casein itself. |
| Calcium, magnesium and zinc Per scoop of Chocolate Supreme: 40% DV calcium, 20% DV magnesium, 100% DV zinc. | 500 mg / 85 mg / 11 mg | Per scoop of Chocolate Supreme: 40% DV calcium, 20% DV magnesium, 100% DV zinc. |
| Acesulfame potassium and sucralose Non-nutritive sweeteners; amounts not disclosed. | — | Non-nutritive sweeteners; amounts not disclosed. |
Nutrition Facts
Serving Size 34 g (About 1 Scoop)
Servings Per Container 53
* Percent Daily Values are based on a 2,000 calorie diet. † Daily Value not established.
Other ingredients: Micellar casein, cocoa powder (processed with alkali), natural and artificial flavor, salt, gum blend (guar gum, gum acacia, xanthan gum), sunflower and/or soy lecithin, magnesium oxide, acesulfame potassium, sucralose, zinc sulfate (monohydrate form).
Contains: Milk and soy.
Flavors & variants
Testing & quality
Gold Standard 100% Whey, Gold Standard 100% Isolate, Essential AMIN.O. Energy, Creatine and Glutamine are Informed Choice certified (per the brand); other products are not all certified, so check each label.
Goals it supports
Independent creators reviewing Gold Standard 100% Casein on TikTok and YouTube.
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