Our ReviewOptimum NutritionSerious Mass

Designed for serious mass gain, Optimum Nutrition's Serious Mass packs 1250 calories, 50g protein, and a comprehensive vitamin-mineral blend.
Optimum Nutrition Serious Mass

Today, we're diving into a review of Optimum Nutrition's Serious Mass. If you're no stranger to the world of protein powders, you'll appreciate that this product is a heavyweight in the mass gainer category. With a serving size of two heaped scoops (334g), it packs a whopping 1250 calories, 50g of protein, and 252g of total carbohydrates. Fat content? A modest 4.5g per serve.

Optimum Nutrition, a brand that's been around for decades, designed this product with one goal in mind: to help you gain serious mass. And more recently they've thrown in a lot more than just protein to get you there. The ingredient list boasts a blend of whey protein concentrate, calcium caseinate, and egg albumin, among others. Plus, it's fortified with a vitamin and mineral blend that covers everything from Vitamin A to Zinc. Creatine Monohydrate and L-glutamine are also in the mix, aimed at enhancing muscle recovery and performance.

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Alright, let's dig in, shall we? First off, the protein blend is a mix of whey protein concentrate, calcium caseinate, and egg albumin. If you're familiar with protein types, you'll know that this is a pretty solid lineup. Whey protein concentrate is fast-absorbing, making it great for post-workout recovery. Calcium caseinate, on the other hand, is slow-digesting, providing a steady release of amino acids. Egg albumin is a high-quality protein that's rich in essential amino acids. So, you're getting a well-rounded protein profile here.

Protein Matrix
Whey Concentrate
Micellar Casein
Egg Albumin
Sweet Dairy Whey

The carb source is primarily maltodextrin, a high-glycemic carb that's good for quick energy replenishment but not so great if you're watching your sugar levels.

Now, let's talk about the extras. This product is fortified with a vitamin and mineral blend that covers a wide spectrum of nutrients. Plus, it includes Creatine Monohydrate and L-glutamine, which are known for enhancing muscle recovery and performance. These are nice touches that add value to the product.

However, there are a few things to be cautious about. The product contains artificial sweeteners (955, 950) and emulsifiers like soy lecithin. If you're trying to steer clear of artificial stuff or have a soy allergy, this might be a concern for you.

One thing we'd love to see added is a digestive enzyme blend. Given the high caloric and protein content, some people might find this product a bit heavy on the stomach. Enzymes could make it easier to digest.

Overall, the ingredient list is pretty solid, but there's room for improvement, especially in terms of digestive aids and natural sweeteners.

Reviewed Product
 Serious Mass
Reviewed Flavor
Product Ingredients
Maltodextrin, Protein Blend (Whey Protein Concentrate [MILK], Calcium Caseinate [MILK], Egg Albumin, Sweet Dairy Whey [MILK])(Emulsifier: Soy Lecithin), Cocoa Powder (Emulsifier: Soy Lecithin), Flavors, Vitamin and Mineral Blend (Potassium Citrate, Magnesium Aspartate, Dipotassium Phosphate, Dicalcium Phosphate Anhydrous, Ascorbic Acid, Ferrous Fumarate, Zinc Sulfate, Vitamin E Succinate, Niacinamide, Beta Carotene, Manganese Sulfate, D-Biotin, Copper Gluconate, Selenomethionine, Pyridoxine HCl, Calcium d-Pantothenate, Riboflavin, Thiamin Mononitrate, Cholecalciferol, Potassium Iodide,Chromium Chloride, Cyanocobalamin, Folic Acid, Sodium Molybdate), L-Glutamine, Creatine Monohydrate, Sweeteners (955, 950), Medium Chain Triglycerides Powder.
Label Endorsed As
milk, soy



When it comes to effectiveness, Optimum Nutrition's Serious Mass is designed to do one thing exceptionally well: help you gain mass. And the nutritional profile suggests it's well-equipped for the job. With a hefty 1250 calories per serving, it's clear that this product is not messing around. The 50g of protein per serving is a substantial amount, aimed at supporting muscle growth and repair, especially when you consider the blend of fast and slow-digesting proteins.


Whey protein concentrate is quick to absorb, making it ideal for post-workout recovery. Calcium caseinate releases amino acids more slowly, providing a sustained protein supply. This combination ensures that you're getting a steady influx of essential amino acids, which is crucial for muscle synthesis and recovery.

The 252g of carbohydrates, primarily from maltodextrin, serve as a quick energy source. This is particularly useful for those who have high caloric needs or struggle to consume enough calories through whole foods alone. The carb content is balanced with a modest 4.5g of total fat, ensuring that the focus remains on muscle gain rather than fat accumulation.

The product also includes Creatine Monohydrate and L-glutamine, which are known for their roles in muscle recovery and performance. Creatine helps in quick energy replenishment during high-intensity workouts, while L-glutamine aids in muscle recovery, making the product even more effective in achieving its intended purpose.



Ah, the Chocolate flavor of Optimum Nutrition's Serious Mass. Let me tell you, it's a classic for a reason. First off, the taste is rich and satisfying without being overly sweet. I've tried my fair share of chocolate-flavored protein powders, and this one strikes a nice balance. It doesn't have that artificial aftertaste that you get with some others.

It's smooth but not too thick, which is a win in my book. Some mass gainers can feel like you're drinking cement, but not this one. It's creamy enough to feel indulgent but not so much that you can't finish a serving.

Mixability is another strong point. I've mixed it with both water and milk, and it dissolves well in both. With water, it's a bit lighter, which is great if you're in a rush or don't want something too heavy. With milk, it becomes a creamy delight, almost like a milkshake. Either way, you're not going to be left with clumps at the bottom of your shaker.

Compared to other products, I'd say Serious Mass holds its own in the taste department. It's not gourmet chocolate, but for a mass gainer, it's pretty darn good.

The only slight drawback is that it can be a bit too rich for some people, especially if you're not a fan of strong chocolate flavors. But hey, that's a personal preference.



When it comes to value, Optimum Nutrition's Serious Mass is a standout, especially considering its cost-to-volume ratio. Despite being one of the more affordable options on the market, it doesn't skimp on quality or effectiveness. With 1250 calories, 50g of protein, and a comprehensive vitamin and mineral blend per serving, the value you're getting is exceptional.

Relative Cost

In terms of market positioning, I'd place it squarely in the mid-range category, making it an even more attractive option for those looking to gain mass without breaking the bank. The protein blend is robust, combining whey concentrate, calcium caseinate, and egg albumin—all high-quality sources. Add to that the extras like Creatine and L-Glutamine, and you've got a product that offers incredible bang for your buck.

Compared to other similar products, Serious Mass is a clear winner in the value department. Many mass gainers either cut corners on protein quality or lack the additional nutrients that this product offers.



Optimum Nutrition's Serious Mass in Chocolate flavor is a compelling option for those looking to gain mass effectively. With a well-rounded protein blend of whey concentrate, calcium caseinate, and egg albumin, it offers both quick and sustained amino acid release. The product also excels in its comprehensive nutritional profile, including a robust vitamin and mineral blend, Creatine, and L-Glutamine.

When compared to the competition, Serious Mass not only holds its own but excels, particularly in terms of ingredient quality and cost-effectiveness. It's one of the more affordable options out there, making it an excellent choice for those on a budget without compromising on nutritional benefits.

Optimum Nutrition Serious Mass

Where to buy?

We recommend Amazon, as they consistently provide the best prices and quickest shipping.

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