Mass Gainer vs Whey Protein: Which Should You Take?

UK Fitness Pro
UK Fitness Pro
· 11 min read
Mass gainer and whey protein on a set of scales

The main difference between mass gainers and protein powders is that mass gainers contain more carbs and less protein, and protein powders contain fewer carbs and more protein. As protein can help you to feel full (1), requires more energy to metabolise (2), and doesn't spike insulin and fat storage as much as carbohydrates (3), people looking for lean muscle growth often use protein powders, whereas those who struggle to gain weight (i.e., "hard gainers") sometimes use mass gainers. 

A bag of whey protein

Below, we take a closer looker at how mass gainers (aka "weight gainers") differ from protein powders in terms of how much protein, carbs, fats, and calories they have. Although there are many types of protein powders, we'll focus on whey protein powder, a by-product of cheese production that is often considered the "gold standard" protein powder and is probably the most popular type of protein. However, we'll also consider the differences between the two main types of whey protein powders: whey protein concentrate and whey protein isolate (the purest form of whey protein). 

Differences in Protein Content

The Mayo Clinic says that those who engage in frequent strength training, resistance training, or endurance training should aim for 1.2–1.7 grams of protein per kilo of body weight per day. In the UK, the average weight of a male is 85 kilos. Someone of this weight would, therefore, aim for 102–144.5 grams of protein per day. If you're looking to develop a lean physique and lose unwanted fat, you'll want to reach your protein target by using a dietary supplement that is high in protein and, thus, low in carbs and fats. 

The table below shows how much protein is in supplements from renowned suppliers, including Myprotein (MP) and  Bodybuilding Warehouse (BW). 

Table 1. Grams of Protein in Whey Protein Concentrates and Isolates and in Mass Gainer Per 100 Grams

SupplementGrams of Protein 
BW Whey Concentrate80.1
MP Whey Concentrate73.0
Grenade Whey Concentrate77.5
BW Whey Isolate95.0
MP Whey Isolate81.0
Warrior Mass Gainer22.0
MP Weight Gainer31.0

As you can see from the table, whey concentrates (top three rows) are about three-quarters protein, whey isolates (next two rows) have even more protein, and mass/weight gainers (bottom two rows) have the least. 

For this reason, people like Chris Bumstead (a world-champion professional bodybuilder) use whey protein to ensure a high daily protein intake and to develop lean muscle mass. Whey proteins are excellent for stimulating muscle protein synthesis (4) and developing muscle (5) as they contain all amino acids, which means they contain all essential amino acids (those the body can't make itself), including the branched-chain amino acids (BCAAs). 

Differences in Carbohydrate Content

As suggested above, carbohydrates may promote weight gain more than proteins as they're less satiating (1), easier to metabolise (2), and are more likely to spike insulin and fat storage (3). Therefore, if you want to prioritise healthy weight gain over weight loss, a supplement with more carbohydrates may be a better choice. 

The table below shows how many grams of carbohydrates are in whey concentrates and isolates in comparison to mass gainers. 

Table 2. Grams of Carbohydrates in Whey Protein Concentrates and Isolates and in Mass Gainer Per 100 Grams

SupplementGrams of Carbohydrates 
BW Whey Concentrate4.7
MP Whey Concentrate6.5
Grenade Whey Concentrate4.8
BW Whey Isolate1.0
MP Whey Isolate4.6
Warrior Mass Gainer64.4
MP Weight Gainer50.0

As shown in the table, whey concentrates (top three rows) are about 5% carbs, whey isolates (next two rows) are a little less, and mass/weight gainers (bottom two rows) are at least half carbs. So, if you're trying to gain weight, go for a mass gainer, and go for a whey protein concentrate or isolate if you want to keep weight off.

If you fall into the latter camp, you might want to check out our article on the best protein supplements for weight loss. You might also be interested in Myprotein's diet whey protein blend

Differences in Fat Content

Per 1 gram, fat has about 9 calories and protein and carbs each have about 4 calories (6). Therefore, if you struggle to gain weight, you may benefit from a supplement that has more fat. 

The table below shows how many grams of fat are in whey concentrates and isolates in comparison to mass gainers. 

Table 3. Grams of Fat in Whey Protein Concentrates and Isolates and in Mass Gainer Per 100 Grams

SupplementGrams of Fat 
BW Whey Concentrate5.7
MP Whey Concentrate6.2
Grenade Whey Concentrate4.5
BW Whey Isolate1.0
MP Whey Isolate1.1
Warrior Mass Gainer3.3
MP Weight Gainer6.2

As you can see, there's little difference between whey protein concentrates (first three rows) and weight gainers (bottom two rows) in terms of how much fat they have. However, whey protein isolates tend to have a little fat, so this may be the best option for those whose priority is to avoid gaining body fat, but it might not be a great option for those who want to put on weight. 

Differences in Calories

Although it's not quite this simple, you tend to put on weight when your caloric intake is greater than the number of calories you burn (i.e., when you're in a caloric surplus), and you tend to lose weight when you consume fewer calories than you burn (i.e., when you're in a caloric deficit). The NHS recommends a daily calorie intake of approximately 2,000 calories for women and 2,500 calories for men, though the number depends on factors like age, size, and activity level. For instance, a large, active individual like Chris Bumstead eats over 4,000 calories per day to maintain his physique. 

The table below shows how many calories there are in whey concentrates and isolates in comparison to mass gainers. 

Table 4. Calories in Whey Protein Concentrates and Isolates and in Mass Gainer Per 100 Grams

BW Whey Concentrate375
MP Whey Concentrate376
Grenade Whey Concentrate370
BW Whey Isolate374
MP Whey Isolate359
Warrior Mass Gainer378
MP Weight Gainer387

As shown in the table, there's not actually much difference between whey protein supplements and mass gainer supplements in terms of calories. Thus, the major difference between these supplements is that mass gainers are much higher in carbs than protein powders. However, if you would like to increase your calorie count, you could consider different types of supplements, like the hemp protein powder from Bodybuilding Warehouse, which has over 400 calories per 100 grams. 

Alternative Sources of Calories

As suggested in our article on the best protein supplements for weight gain, you could also get extra calories from protein bars (Table 5) or nut butters (Table 6) if you get tired of taking your protein a powder form.

Table 5. Comparison of Myprotein's Milk-Based Protein Bars With Respect to Their Calories and Macronutrients 

Supplement TypeCalories per 100gProtein (g per 100g)Carbs (g per 100g)Fats (g per 100g)
Layered Protein Bar354333410
Impact Protein Bar357313213
Crispy Layered Bar353273715
Protein Break Bar526163739
Breakfast Layered Bar423263221

Myprotein's Protein Break Bar has over 500 calories and 37 grams of carbs per 100 grams, so it would be ideal for someone seeking healthy weight gain. On the other hand, their Impact Protein Bar has just 357 calories and 32 grams of carbs per 100 grams, so would be a better option for someone looking to keep the weight off. 

Table 6. Comparison of Myprotein's Nut Butters With Respect to Their Calories and Macronutrients 

Nut Butter TypeCalories per 100gProtein (g per 100g)Carbs (g per 100g)Fats (g per 100g)
All-Natural Peanut Butter615301248
All-Natural Almond Butter644246.457
All-Natural Cashew Butter637201853
All-Natural Triple Nut Butter622251350

Nut butters have a lot of healthy fats (7), so they are very high in calories and would be a great choice if you want to ensure you're getting enough calories. For instance, Myprotein's Almond Butter has 644 calories per 100 grams, meaning that each 1-kg tub has 6,440 calories! Perfect if you're a skinny guy trying to put on some mass!

The Benefits of Mass Gainers and Protein Powders

There's much more research on the benefits of whey protein protein compared to mass gainers. However, many mass gainers use whey protein as the primary protein source or use a combination of proteins that includes whey protein. For instance, "milk protein" on a list of ingredients likely indicates a combination of whey and casein proteins

Muscle Building

A study published in the International Journal of Sport Nutrition and Exercise Metabolism (5) found that supplementing with whey protein isolate led to significant muscle gain among recreational bodybuilders following a 10-week resistance training programme. Additionally, the participants lost fat and experienced significant increases in strength as assessed by one-rep max on cable pull-down, squat, and bench press.           

An image representing a man building muscle due to whey protein

The participants consumed 1.5 grams of whey protein isolate per kilo of body weight per day, which would equate to 127.5 grams for an 85-kilo individual. As a scoop of protein is about 30 grams, you'd need about four scoops to get this amount of protein. As isolates could be thought of as the "purest form of protein", you might need to consume a little more if using a whey concentrate, which will likely have about 10% less protein. 

In terms of its ratio of protein to other macronutrients, the best whey protein powder that we've considered here is the whey isolate from Bodybuilding Warehouse, which can be considered a very pure protein in that 100 grams contains 95 grams of protein. Therefore, a protein shake with 30 grams of powder would contain 28.5 grams of protein. 

Since mass gainers typically have about one-third as much protein as whey protein powders, you would likely need to consume about twelve 30-gram scoops to consume as much protein as the participants in the study. Therefore, whey protein powders represent a much more convenient way of ensuring that you get enough protein to experience significant muscle tissue growth following resistance training. 

Muscle Recovery

A study published in Nutrients (8) found that having 25 grams of whey protein immediately after and 10 hours after exercise was associated with significantly greater strength and power the following day compared to placebo, suggesting that whey protein likely assists with muscle recovery. As the amount of protein consumed by the participants in this study was quite modest, it wouldn't be unreasonable to consume an equal amount through a mass gainer instead of a whey protein powder. For example, a serving of mass gainer may contain about 30 grams of protein (e.g., a 100-gram serving of Myprotein's weight gainer has 31 grams), so you'd need less than two servings. 

Other Considerations

Artificial Sweeteners

It's common for flavoured versions of whey protein powders and mass gainers to contain artificial sweeteners such as sucralose. If you'd prefer to avoid these, you can usually find unflavoured versions that shouldn't contain artificial sweeteners. 

Maintaining a Well-Balanced Diet

Even if you hit your macros with protein powders and mass gainers, a healthy diet is one that includes real foods rich in micronutrients. Therefore, rather than making mass gainers your only carbohydrate source, incorporate natural sources into your diet like sweet potatoes, which contain beta carotene (a precursor of vitamin A, important for skin, immune, and eye health) and anthocyanins, which may minimise the risk of diabetes, cancer, and cardiovascular disease (9, 10). Likewise, rather than making protein powder your only source of protein, try to also get protein from whole foods like eggs, which contain omega-3 fatty acids (linked to reduced muscle soreness; 11) and vitamin D (linked to a reduced risk of bone and muscle pain). 

Sweet potato fries

However, during times when it's difficult to access whole foods (e.g., during travel), you could consider using a meal replacement to increase your micronutrient intake. For example, Myprotein's protein meal replacement powder is enriched with a wide range of vitamins and minerals and includes a balance of macronutrients suitable for a range of fitness goals (34 grams of protein, 34 grams of carbs, and 13 grams of fat per 100 grams). 


Thus, mass gainers and protein powders are intended for slightly different purposes. While mass gainers don't necessarily have a lot of added calories compared to protein powders, their high carbohydrate content may make them more suitable for someone with a "hard gainer" body type whose main priority is weight gain. On the other hand, protein powder may be the right supplement for someone whose main focus is on developing a lean muscular physique. 

You might also like our articles on the best protein powders for seniors, protein bars and powders, and the best protein sources for diabetics. If you're interested in other supplements that can increase athletic performance, you might like our articles on how whey protein compares to pea protein, how creatine compares to whey protein and the benefits of creatine monohydrate

About the Author

Dave Robinson, a co-founder of, has a background in psychology (BSc) and neuroscience (MSc, PhD). As well as strength training, he enjoys endurance challenges and has run ultramarathons, cycled across several countries, and completed the Three Peaks Challenge. When writing, he draws on scientific evidence to understand the pros and cons of different diets, supplements, and training regimes. 

The author riding a bike


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