Optimum Nutrition Serious Mass Review

Quick Summary

• 🍫 1250 calories per serving – perfect for hardgainers and those in bulking phases.
• 💪 50g of protein from a sustained-release blend (whey, casein, egg, dairy).
• 🍞 254g of carbohydrates – mostly from maltodextrin for rapid glycogen replenishment.
• ⚡ 3g of creatine monohydrate to support strength and size.
• 🧠 Choline, inositol & MCTs included for added energy and metabolic support.
• 🧪 25+ vitamins and minerals to fill dietary gaps.
• 🥤 Tastes great and blends smoothly (best in a blender).
• 📦 Available in 2.72kg, 5.45kg, and 10.9kg tubs at Mr Supplement.

What is Optimum Nutrition Serious Mass?

Serious Mass by Optimum Nutrition is a calorie-packed mass gainer designed for anyone struggling to put on weight. Owned by Glanbia, one of the world’s largest whey manufacturers, Optimum Nutrition delivers quality formulas—and Serious Mass is no exception.

Why Use Serious Mass?

Whether you’re an ectomorph, a hard-training athlete, or simply someone with a fast metabolism, this shake offers:

• 🔥 1250 calories per serve
• 🧬 50g of high-quality protein
• 🥔 254g of carbohydrates (only 21g from sugars)
• ⚡ 3g of creatine monohydrate
• 🧠 Nutrients like glutamine, choline, inositol, and MCTs
• 🥦 A complete vitamin/mineral complex

It’s more than a protein shake—Serious Mass is a full meal in a scoop (or two).

First Impressions & Nutritional Breakdown

You can’t call Serious Mass a typical protein powder—it’s a full-on calorie bomb 💣. It delivers more than double the calories of a standard meal. The protein blend includes:

• Whey Protein Concentrate
• Calcium Caseinate
• Egg Albumin
• Sweet Dairy Whey

This combo provides fast, medium, and slow-digesting protein sources—perfect for prolonged muscle support.

🧁 The carb-to-protein ratio is about 5:1, making it ideal for recovery, growth, and glycogen replenishment.

Standout Ingredients

Flavour & Mixability

Despite being a large serving (336g), it mixes surprisingly well in a blender. 🌀 The texture is smooth and creamy—especially when mixed with milk. Shaker bottles work for smaller serves.

🍫 Chocolate is the most popular flavour, but other options are available depending on your preference.

How to Use Serious Mass

Use Serious Mass in a few different ways based on your goals:

• 🏋️ Post-Workout: Drink ½ to 1 serve 30–45 mins after training
• 🥪 Between Meals: Maintain a high daily calorie intake
• 🌙 Before Bed: Promote overnight recovery and muscle growth

👉 Beginners should start with ½ serving per day, increasing gradually.

💡 Pro Tip: Blend it with milk, oats, banana, or peanut butter for even more calories and flavour.

Who Is It For?

Serious Mass is ideal for:

• 🧍‍♂️ Hardgainers or those with a fast metabolism
• 🏋️‍♂️ Athletes during bulking phases
• 🚗 Busy people needing a meal replacement
• 🤕 Individuals recovering from injury or illness

It’s not recommended for anyone on low-carb diets or prone to fat gain.

Any Downsides?

While Serious Mass is effective, here are a couple of things to consider:

• ❌ High maltodextrin content – quick-digesting, but may spike blood sugar
• 🥜 Low in healthy fats – could benefit from added unsaturated fats for nutrient balance

Available Sizes at Mr Supplement

📦 Choose the size that suits you:

• 🥄 2.72kg (6lb) – perfect for beginners
• 🧴 5.45kg (12lb) – great value for regular users
• 🏋️ 10.9kg (24lb) – serious size for serious gainers

Explore Serious Mass on the Optimum Nutrition brand page, or browse other options in our Mass Gainer category.

Final Verdict

💯 Optimum Nutrition Serious Mass lives up to its name. It’s one of the most calorie-dense, feature-packed mass gainers on the market. For those who’ve tried eating more and still can’t gain, this shake is your new best friend.

High in carbs, loaded with protein, and full of additional support ingredients—it’s a premium option for real results.

References

• Phillips, S. M., Tang, J. E., & Moore, D. R. (2009). The role of milk- and soy-based protein in support of muscle protein synthesis. American Journal of Clinical Nutrition, 90(3), 738S–743S.
• Kreider, R. B., et al. (2007). ISSN exercise & sport nutrition review: research & recommendations. Journal of the International Society of Sports Nutrition, 4(1), 1–43.
• Karpinski, C., et al. (2017). Nutrition recommendations for bodybuilders in the off-season: A narrative review. Sports, 5(4), 76.
• Saunders, M. J., Kane, M. D., & Todd, M. K. (2004). Effects of a carbohydrate-protein beverage on cycling endurance and muscle damage. Medicine & Science in Sports & Exercise, 36(7), 1233–1238.
• Bilsborough, S., & Mann, N. (2006). A review of issues of dietary protein intake in humans. International Journal of Sport Nutrition and Exercise Metabolism, 16(2), 129–152.
• Ziegenfuss, T. N., et al. (2002). Safety and efficacy of creatine pyruvate and creatine citrate. Journal of Strength and Conditioning Research, 16(4), 525–528.

Optimum Serious Mass FAQs

Is Serious Mass good for skinny guys?

Yes, Optimum Nutrition Serious Mass is one of the best supplements for skinny guys (ectomorphs) who find it hard to gain weight. With over 1,200 calories and 250+ grams of carbs per serve, it helps create a calorie surplus needed for muscle and size gains. Its high carb-to-protein ratio supports both weight gain and recovery after intense workouts.

How fast can I gain weight with Serious Mass?

Weight gain results vary, but many users report gaining 0.5 to 1.5kg per week when combining Serious Mass with consistent eating and resistance training. To gain weight effectively, it's best to use Serious Mass daily while also consuming whole food meals and training 3–5 times per week.

Can Serious Mass be used as a meal replacement?

Yes, Serious Mass can act as a high-calorie meal replacement for people with busy schedules or those who struggle to consume enough food. Each shake provides protein, carbs, healthy fats, and essential micronutrients. However, it should supplement—not replace—your whole food diet for best long-term results.

When is the best time to take Serious Mass?

The best times to take Serious Mass are:

• 🏋️ After workouts – to replenish glycogen and kickstart recovery
• 🍽️ Between meals – to increase daily calorie intake
• 🌙 Before bed – to support overnight muscle recovery and growth

Starting with half a serving and working up to a full serving is recommended for new users.

Is Serious Mass safe for long-term use?

Yes, Serious Mass is generally safe for long-term use when taken as directed. It’s important to balance it with whole foods, stay active, and monitor your weight gain to avoid adding excess body fat. Those with health conditions (e.g., diabetes or kidney issues) should consult a healthcare professional before use.

What makes Serious Mass different from other mass gainers?

Serious Mass stands out because of its ultra-high calorie content, large carbohydrate base, and added functional ingredients like creatine, glutamine, MCTs, and a full vitamin/mineral blend. Its 5:1 carb-to-protein ratio makes it more effective for extreme hardgainers than many lower-calorie alternatives.