Mass Gainer vs Whey Protein — Which Should You Take?

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12 May, 2026
Posted by: Buffalo Nutrition

It’s one of the most common questions we get asked in-store: “Should I take a mass gainer or a whey protein?” The short answer depends entirely on your goals, your diet and how your body responds to training. Here’s how to think about it.

What Is Whey Protein?

Whey protein is a pure protein supplement derived from milk. A typical serving delivers 20–32g of protein with relatively low calories — usually 100–150kcal per scoop. It’s designed to help you hit your daily protein target conveniently and efficiently, without adding significant extra calories to your diet.

It’s the most widely used supplement in sports nutrition and one of the most comprehensively researched — the evidence for its role in supporting muscle growth and recovery is overwhelming.

What Is a Mass Gainer?

A mass gainer is a high-calorie supplement that combines protein with large amounts of carbohydrates and sometimes fats. A single serving typically delivers 500–1,250 calories, 50–100g+ of carbohydrates and 30–55g of protein. It’s essentially a calorie-dense meal in shake form.

Mass gainers exist for one specific purpose: helping people gain body weight when they struggle to eat enough calories through food alone.

The Key Differences

Calories per serving: Whey = 100–150kcal. Mass gainer = 500–1,250kcal.
Carbohydrates: Whey = 3–5g per serving. Mass gainer = 50–100g+ per serving.
Primary purpose: Whey = hit protein targets. Mass gainer = hit calorie targets for weight gain.
Cost per gram of protein: Whey protein is significantly cheaper per gram of protein delivered.

Who Should Take Whey Protein?

Whey protein is the right choice if:

You’re eating enough calories but struggling to hit your daily protein target
You’re in a fat loss or body recomposition phase
You’re a healthy weight or above it
You find it hard to eat large meals after training
You want a clean, lower-calorie supplement option

The vast majority of gym-goers — whether cutting, maintaining or in a modest calorie surplus — will get better results from whey protein than from a mass gainer.

Who Should Take a Mass Gainer?

Mass gainers are genuinely useful if:

You’re a classic hardgainer — someone who eats a lot but genuinely struggles to put on weight
You have a very fast metabolism and find it almost impossible to maintain a calorie surplus through food alone
You need to gain significant weight for a sport (rugby, powerlifting, strongman)
You don’t have time to eat enough meals throughout the day and need convenient high-calorie options

Mass gainers are frequently over-used. If you can eat enough through whole foods, you don’t need one. A quality whey protein is better value, easier on your digestion and more flexible.

Our Honest Recommendation

Most people who ask us about mass gainers don’t actually need them. If you’re training hard, eating well and staying consistent, a quality whey protein combined with a modest calorie surplus from real food will deliver better results with fewer digestive issues and less unnecessary fat gain.

That said, if you’re a genuine hardgainer who has been training consistently for months without gaining weight, a mass gainer can be a useful tool to push your daily calorie intake over the line.

Top Picks at Buffalo Nutrition

Best Whey Proteins

Optimum Nutrition Gold Standard Whey — the world benchmark, 24g protein, trusted globally for over a decade
Dymatize ISO100 — high-purity hydrolysed isolate, 25g protein, minimal calories and virtually zero lactose
Applied Nutrition Critical Whey — 32g protein per serving, excellent flavours and outstanding value

Best Mass Gainers

Optimum Nutrition Serious Mass — the gold standard for mass gainers, 1,250kcal per serving, 50g protein
USN Hyperbolic Mass — a popular choice in UK gyms, high-calorie with added creatine
Mutant Mass — a loaded formula for those with serious size and weight gain goals

Both ranges are available in-store and online. Shop whey protein or browse mass gainers.

Not Sure? Ask Us In-Store

Come into Buffalo Nutrition at 132 Cricklewood Broadway, London NW2 3EE and we’ll give you a straight answer based on your goals, training and diet — no upselling, no jargon.