Best Mass Gainers for Skinny Guys (UK): Complete Guide
Gaining weight as a skinny guy can be frustrating. You eat constantly, train hard—but the scale barely moves. That’s where mass gainers come in.
These high-calorie weight gain supplements are made for hardgainers with fast metabolisms. They pack in the protein, carbs, and calories your body needs to build muscle and size—without force-feeding yourself all day.
In this complete UK guide, we’ll review the best mass gainers for skinny guys — covering top brands like Mutant Mass, Serious Mass, and Applied Nutrition. Whether you’re trying to bulk fast, build lean muscle, or gain weight on a budget, this guide has you covered.
👉 Related: Beginner Workout Plan for Skinny Guys to maximise your gains with these supplements.
What Are Mass Gainers and How Do They Help Skinny Guys?
A mass gainer (also called a weight gainer) is a high-calorie supplement packed with protein, carbs, and healthy fats. They’re ideal for skinny guys who struggle to eat enough to gain muscle.
Mass gainers help you create a calorie surplus — the #1 rule for building size.
How to Choose the Best Mass Gainer for Your Body Type
✅ Fast Metabolism? Choose high-calorie mass gainers for rapid weight gain.
✅ Slower Metabolism? Go for lower-calorie, nutrient-dense bulking powders to stay lean.
✅ Struggling to Eat Enough? A weight gainer shake makes it easier to hit your daily calorie target without stuffing yourself.
Best Mass Gainers for Skinny Guys (UK)
🏆 1. Mutant Mass Extreme – Best Overall Mass Gainer for Skinny Guys
- Why it’s the best: Massive calories, high protein, essential fats for maximum size.
- Perfect for: Hardgainers needing fast results.
- Top Stack: Combine with Mutant Creakong CX8 for insane strength gains.
💥 2. Applied Nutrition Critical Mass Original – Best Budget Mass Gainer
- Why we love it: Great calorie count, easy to mix, loaded with essential nutrients.
- Top Stack: Boost gains by adding Applied Nutrition Creatine.
💪 3. USN Hyperbolic Mass – Best for Size & Strength
- Perfect for fast metabolisms: High in carbs and added creatine to fuel monster workouts.
- Top Tip: Great for skinny guys aiming for both weight and muscle.
Best Weight Gainer for Skinny Guys Wanting Lean Muscle
If you want to gain quality muscle without getting fluffy:
🔥 1. USN Muscle Fuel Anabolic – Best Lean Mass Gainer
- Why it works: Lower calorie, nutrient-dense formula for controlled bulking.
- Perfect for: Building size without excessive fat.
🚀 2. Optimum Nutrition Serious Mass – Great Lean Mass Gainer
- Why choose it: A great all round muscle building formular.
- Tip: Start with a half serving if you’re new to mass gainers.
Fast vs Controlled Weight Gain: What’s Best for You?
Fast Gains:
✔ Mutant Mass Extreme
✔ Serious Mass
✔ Critical Mass
➡ Drink your protein for skinny guy immediately post-workout for maximum recovery and muscle growth.
Controlled Gains:
✔ USN Muscle Fuel Anabolic
✔ Whey Protein + Creatine stack
➡ Tip: Add BCAA or amino acid drinks to protect lean muscle if you’re eating lighter.
Understanding Mass Gainers vs Weight Gainers
| Mass Gainer | Weight Gainer | |
| Calories | 300–700 | 500–1,200+ |
| Protein | High (30–50g) | Moderate (15–25g) |
| Carbs | Balanced | Very High |
| Best for | Lean muscle building | Rapid size increases |
Summary:
- Choose a mass gainer if you want lean muscle and controlled bulking.
- Choose a weight gainer if you need to put on weight fast (even if it includes a little fat).
When Should Skinny Guys Take Mass Gainers?
📅 Best Times:
- Post-workout to speed up recovery and muscle growth
- As a meal replacement when you’re too busy to cook
- Before bed if you need extra calories
Final Thoughts: Best Mass Gainers and Bulking Powders for Skinny Guys
Choosing the right protein or bulking powder for a skinny guy depends on your goals:
✅ Best Overall Mass Gainer: Mutant Mass Extreme
✅ Best for Muscle Size: USN Hyperbolic Mass
✅ Best for Lean Muscle: USN Muscle Fuel Anabolic
✅ Best Budget Pick: Applied Nutrition Critical Mass
All of these mass gainers for skinny guys are loaded with calories, high-quality protein, and complex carbs—everything you need to crush your bulking goals.
Start today — your future bigger, stronger self will thank you. 💪