Mass Gainer Comparison: Mutant Mass vs Serious Mass (2026)

Choosing the best mass gainer in Singapore depends on your metabolic rate and caloric needs. Mutant Mass is the superior choice for clean, food-based carbs and multiple protein sources, while Optimum Nutrition Serious Mass is ideal for those who need pure, fast-digesting calories to break through extreme weight gain plateaus.

For fitness enthusiasts training hard in Jurong, Tampines, or anywhere across Singapore, selecting the right high-calorie supplement is the key to unlocking consistent muscle growth and weight gain. In this comprehensive comparison, we pit two of the world's most popular mass gainers against each other to help you decide which one deserves a spot in your supplement stack.

What is a Mass Gainer?

A mass gainer is a high-calorie supplement formulated with a blend of protein, carbohydrates, fats, and sometimes vitamins and minerals. Unlike standard whey protein powders which focus on delivering pure protein with minimal calories, mass gainers are specifically designed to help individuals achieve a caloric surplus. This surplus is essential for muscle hypertrophy and weight gain, particularly for "hardgainers" or those with exceptionally fast metabolisms who find it difficult to eat enough solid food throughout the day.

While standard protein powders like Optimum Nutrition Hydro Whey are perfect for lean muscle maintenance and post-workout recovery, mass gainers provide the calorie density required to fuel heavy lifting sessions and build size.

Mutant Mass Extreme 2500: The Food-Based Bulk

Mutant Mass is legendary in the bodybuilding community for a good reason. It is formulated with a multi-source protein blend and real food ingredients like oats, sweet potatoes, and avocado. This food-based approach provides a sustained release of nutrients, helping to minimize blood sugar spikes and bloating.

At Ultimate Sup, Mutant Mass Extreme 2500 starts from S$54 for a 6 lb bag, up to S$102 for the 12 lb bag. It is a highly cost-effective and premium-quality gainer for athletes who want clean ingredients.

Key Macro Profile (Per Serving of 4 Scoops)

• Calories: 1,100 kcal (mixes to 2,540 kcal when blended with double milk)
• Protein: 56g (from Whey Concentrate, Hydrolyzed Whey, Isolate, Casein, and Milk Protein)
• Carbohydrates: 192g (from clean carbs including maltodextrin, waxy maize, barley, sweet potato, and rolled oats)
• Fats: 12g (including MCT oil and avocado powder)

Pros of Mutant Mass

• High-Quality Protein Blend: Uses multiple sources of protein to supply amino acids to your muscles over several hours.
• Whole Food Carbohydrates: Contains sweet potato, oats, and barley, which are easier on the stomach.
• Incredible Taste: Notoriously delicious flavors, especially Triple Chocolate and Cookies & Cream.
• High MCT Fat Content: Fats from MCTs and avocados provide quick energy instead of stored body fat.

Cons of Mutant Mass

• Large Serving Size: Four large scoops can be difficult to mix without a high-powered blender.
• Slightly Thick Consistency: The inclusion of oat and barley fibers makes the shake quite thick.

Optimum Nutrition Serious Mass: The High-Calorie Monster

Optimum Nutrition Serious Mass is designed for the ultimate hardgainer. If you have an extremely fast metabolism and struggle to gain even a single kilogram, Serious Mass is formulated to provide an overwhelming dose of calories and carbohydrates to force your body into a growth state.

At Ultimate Sup, ON Serious Mass is priced from S$49 for a 6 lb bag, offering competitive value for budget-conscious gym-goers looking for simple, fast-digesting calories.

Key Macro Profile (Per Serving of 2 Scoops)

• Calories: 1,250 kcal
• Protein: 50g (from Whey Concentrate, Calcium Caseinate, and Egg Albumin)
• Carbohydrates: 252g (primarily from fast-digesting maltodextrin)
• Fats: 4.5g (low fat profile to maximize carb space)
• Added Creatine & Glutamine: 3g of creatine monohydrate per serving to boost strength.

Pros of ON Serious Mass

• Extreme Caloric Density: 1,250 calories per serving makes achieving a caloric surplus effortless.
• Added Creatine: Saves you from having to purchase a separate creatine supplement.
• Fast-Digesting Carbs: Excellent post-workout option to quickly replenish glycogen stores.
• Vitamins & Minerals: Enhanced with 25 essential vitamins and minerals to support overall health.

Cons of ON Serious Mass

• High Maltodextrin Content: Can lead to rapid blood sugar spikes and crashes if taken during the day.
• Lower Fat Content: Lacks the healthy dietary fats found in Mutant Mass.
• Potential Bloating: The high volume of simple carbs can cause mild digestive discomfort for some users.

Head-to-Head Comparison: Mutant Mass vs. Serious Mass

When we compare these two gainers, the main differences lie in the quality of ingredients and the carb-to-protein ratio.

1. Digestion and Clean Ingredients

Mutant Mass easily wins on ingredient quality. By incorporating oats, barley, and sweet potatoes, it provides complex carbohydrates that digest slowly. Optimum Nutrition Serious Mass relies heavily on maltodextrin. While maltodextrin is great for quick post-workout recovery, it can cause energy crashes if consumed at other times of the day.

2. Muscle Recovery and Protein Blend

Mutant Mass provides 56g of protein from five different sources, including fast-absorbing whey isolate and slow-digesting micellar casein. This ensures your muscles receive a steady flow of amino acids over several hours. ON Serious Mass offers 50g of protein from three sources, which is still highly effective but less comprehensive than Mutant's blend.

Alternative Choice: PVL Clean Mass XL

If you are looking for an alternative in-stock option that bridges the gap between clean ingredients and massive calorie counts, PVL Clean Mass XL is a phenomenal Choice.

PVL Clean Mass XL provides 560 calories, 30g of protein, and a clean food-based carbohydrate blend featuring fermented pea starch, organic quinoa, and brown rice. It is certified by Informed-Choice, meaning it is tested for banned substances and is incredibly gentle on the stomach. For athletes who prioritize clean nutrition and premium certifications, you can also read our PVL Iso Gold Whey Protein Review.

Where to Buy Authentic Mass Gainers in Singapore?

To avoid counterfeit supplements and ensure you are buying 100% authentic products, buy directly from Ultimate Sup. We are Singapore's premier online supplement store, offering direct distribution, competitive pricing, and fast shipping.

Whether you choose the clean food macros of the Mutant Collection or the sheer calorie density of the Mass Gainer Collection, Ultimate Sup delivers your supplements straight to your doorstep across Singapore with next-day delivery options.

Frequently Asked Questions

Which gainer is better for beginners in Singapore?

Mutant Mass is generally better for beginners because its food-based carbohydrates are easier on the stomach and less likely to cause bloating compared to the high-maltodextrin formula of ON Serious Mass.

Can I take a half serving of these mass gainers?

Yes, taking a half serving (e.g., 2 scoops of Mutant Mass or 1 scoop of Serious Mass) is highly recommended for beginners to assess tolerance and prevent digestive discomfort.

Does Serious Mass contain creatine?

Yes, ON Serious Mass contains 3 grams of creatine monohydrate per full serving. Mutant Mass does not contain creatine, so you will need to supplement it separately if strength is your goal.

Does Ultimate Sup offer next-day delivery in Singapore?

Yes, Ultimate Sup offers fast, reliable next-day delivery across Singapore, ensuring you never run out of your favorite mass gainers during a bulk.

About the Author

Hailey Pham is a Dietetics & Performance Specialist at Ultimate Sup. She holds a degree in Human Nutrition and specializes in sports dietetics, helping competitive athletes and everyday gym-goers optimize their meal plans, caloric intakes, and supplement stacks for peak athletic performance.