Quick take
Choosing a protein powder is really a question of timing and calorie target. Do you want support while you sleep, a big calorie surge after a hard session, or a lean shake that keeps carbs low? These four products answer those jobs differently, and their listed prices run from $31.19 for a 3 lb Serious Mass container to $118.99 for a 5 lb ALLMAX Isoflex tub.
If you want a slow-release casein for between meals or before sleep, the two Optimum Nutrition Gold Standard Casein tubs are your match. If you need dense calories for a mass-building routine, Serious Mass is the high-calorie choice at the lower end of the price range. If you want a very high protein isolate with a long supply, ALLMAX Isoflex is the largest tub in this set.
Listed price comparison
| Product | Listed price | Price indicator |
| Optimum Nutrition Gold Standard Casein Protein, Chocolate Peanut Butter, 4lb | USD 84.99 | |
| Optimum Nutrition, Gold Standard 100% Casein, 3.86lb | USD 84.99 | |
| Optimum Nutrition Serious Mass Chocolate Weight Gainer Protein Powder 3 lb | USD 31.19 | |
| ALLMAX Nutrition Isoflex Whey Protein Isolate, 5 lb chocolate | USD 118.99 | |
Decision matrix
| Goal | Start here | Why |
| Overnight or between-meal support | Gold Standard 100% Casein | Casein formulation for slow delivery |
| Chocolate peanut butter flavor | Gold Standard Casein Protein Chocolate Peanut Butter | Same casein approach in the chocolate peanut butter flavor |
| High-calorie mass-building shake | Serious Mass Chocolate | 1,260 calories and 50g protein per 2-scoop serving |
| Lean high-protein shake with a long supply | ALLMAX Isoflex | 90% protein isolate with 76 servings |
Product notes
Optimum Nutrition Gold Standard Casein Protein, Chocolate Peanut Butter, 4lb
Choose this tub when you want a casein shake in a specific flavor. It is formulated with slow-digesting micellar casein, provides 24g of protein per scoop, and can be used between meals or at bedtime to support overnight recovery. It is a Powder formulation in New condition. The chocolate peanut butter profile gives it a more dessert-like position in this lineup, but that also means it won't suit someone who prefers plain vanilla; the 3.86 lb vanilla casein tub is the sibling option.
Optimum Nutrition, Gold Standard 100% Casein, 3.86lb
The creamy vanilla version of Gold Standard 100% Casein is the one to grab if a straightforward flavor matters as much as function. Each scoop delivers 24g of micellar casein, and the active ingredients include Calcium, Magnesium, Protein, and Zinc. It fits an overnight recovery routine and is a 3.86 lb tub with a 1-scoop serving direction. The catch is the same as any casein here: it is not built for the high-calorie weight-gain job that Serious Mass handles. If you want serious calories plus protein, you would need to go the separate mass-gainer route.
Optimum Nutrition Serious Mass Chocolate Weight Gainer Protein Powder 3 lb
Serious Mass is the calorie-dense pick in this set. A 2-scoop serving provides 1,260 calories, 50g protein, 253g carbohydrates, plus 25 vitamins and essential minerals. That makes it useful for a higher-calorie nutrition plan or for after workouts when the goal is weight gain. The trade-off is portion count: this 3 lb container is portioned at 4 servings per container, so it won't last as long as the isolate or the larger casein tubs in this comparison. It is listed as gluten-free.
ALLMAX Nutrition Isoflex Whey Protein Isolate, 5 lb chocolate
Isoflex is the isolate-focused option, with 90% protein content sourced from native and intact, non-denatured whey protein fractions. The 5 lb chocolate tub lists 76 servings, which makes it a long-format choice if you want fewer container changes. It also includes SCOOP-LOCK, a scoop-storage feature that avoids digging through the powder. Choose it when you want a straightforward high-protein chocolate shake; the limitation is that this is a whey isolate, so it is a leaner format rather than an overnight casein support or a high-calorie mass-gainer serving.
Final recommendation by use case
For overnight recovery and satiety, choose Gold Standard 100% Casein: the creamy vanilla version if you want a simple shake, or the chocolate peanut butter version if flavor is part of the routine. For a calorie-heavy weight-gain plan, Serious Mass Chocolate is the fit. For a lean high-protein shake, ALLMAX Isoflex is the isolate pick. Think of these as different tools: casein for slower release, Serious Mass for calorie pushing, and Isoflex for a concentrated protein shake.
