Mass Gainer or Whey Protein For Skinny Guys: Which Is Best?

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Mass gainers and whey protein are recommended for building muscle and gaining weight. However, the two supplements are not the same, so it’s essential to understand the differences and their unique benefits to see which one makes the most sense for you. 

Key Takeaways

Prefer to watch? Check out our video of Mass Gainer vs Whey Protein.
  • You should consume up to 200 calories above your maintenance calories to gain weight and build muscle. Getting calories from a mass gainer on top of your whole foods diet can help you achieve this intake more easily for steady weight gain.
  • Whey protein powder primarily consists of protein and has almost no carbs or fat. Because of that, it offers fewer calories than a mass gainer and would be the better option if you only want to get extra protein and can otherwise maintain a calorie surplus with your diet alone.
  • You can take mass gainers and whey protein together. For example, have a serving of a mass gainer on days when you don’t feel as hungry and struggle to eat enough calories and supplement with whey protein when you only need to add extra protein to your meals.

Medical Disclaimer: The material presented in this article aims to offer informational insights. It should not be perceived as medical guidance. The views and writings are not designed for diagnosing, preventing, or treating health issues. Always consult with your physician prior to starting any new dietary or supplement routine.

4 Differences Between Mass Gainer & Whey Protein

Differences Between Mass Gainer and Whey Protein

1. Calories Per Serving

One of the differences between mass gainers and whey protein is the number of calories per serving. 

Mass gainer has significantly more calories per serving––typically 500 to 1300, depending on the brand.

Whey protein powders range from 115 calories to 150 calories per serving, also depending on the brand.

A higher-calorie supplement is better for those who want to add mass and struggle to eat enough calories from food to support their goals.

A lower-calorie supplement is best for those who only want to gain lean mass and limit fat mass and those who don’t struggle to eat enough calories from food to support their goals.

2. Macronutrient Contributions

Another key difference between mass gainer and whey protein powder is their macronutrient distribution. 

Mass gainers are higher in carbs and fats than protein, but whey protein is higher in protein than carbs and fats.

For example, a serving of the Transparent Labs Mass Gainer (two scoops, 197 grams) has:

Transparent Labs Mass Gainer
  • 53 grams of protein
  • 109 grams of carbs
  • 12 grams of fats
  • 740 calories

In contrast, a serving of Transparent Labs Whey Protein (one scoop, 32 grams) has:

  • 28 grams of protein
  • 2 grams of carbs
  • 0 grams of fats

Mass gainer is more of a meal replacement because it has all three macronutrients.

Whey protein powder is likely only one component of a meal or a snack itself because it only has protein and very few carbs and fats.

3. Extra Calories vs. Extra Protein

A mass gainer is intended for people who struggle to eat enough calories and maintain a surplus, or are hard gainers and require a lot of calories above and beyond their “maintenance calories” to bulk. 

An example would be someone naturally skinny who struggles to maintain a calorie surplus on a relatively clean diet. A serving of mass gainer would more easily supply the calories to create a surplus.

Aiming for a surplus of 50 to 200 calories over maintenance calories is generally recommended. 

For example, if you maintain your body weight at 2,500 calories, start with up to 2,700 calories and monitor your body weight.

A bigger surplus might seem enticing, but it’s generally not a good idea because it leads to significant fat gains without helping you build more muscle.

Given whey protein’s lower calorie content per serving (around 120 calories), it’s ideal to help reach the muscle-gaining target of 1.6-2.2 grams of protein per kilogram of body weight if you can maintain a calorie surplus through diet alone. 

4. Cost And Affordability

Given their unique nutritional profile and intended use, mass gainers cost more per serving than whey protein. 

To use Transparent Labs as an example again, a serving of their whey protein costs around $2, whereas a serving of their mass gainer costs approximately $5.30.

Of course, it’s worth noting that a serving of a mass gainer can be 5-6 times bigger than that of a whey protein.

When Should You Take Mass Gainer? My Recommendation As A Former Skinny Guy

Take a mass gainer if you struggle to maintain a calorie surplus and gain weight. 

For example, if your maintenance is 2,500 and you add 200 to create a surplus, you’d need to eat 2,700 calories.

If that’s unsustainable (for example, you feel stuffed all the time), having a mass gainer serving can provide 500+ calories, making it easier to reach your daily target.

It’s important to know that drinking a mass gainer alone won’t automatically make you gain weight, though.  

You need to understand your maintenance calories (use this calculator) and then strategically track your calories (use this app) to ensure you’re achieving the necessary surplus.

When Should You Supplement With Whey Protein If You Want To Bulk?

Consider whey protein if you can comfortably eat enough food to maintain a calorie surplus but need help reaching the recommended 1.6-2.2 grams of protein per kilogram of body weight (0.7-1 gram per pound).

If you can eat enough calories but struggle to hit your protein target, you’re at risk of gaining more fat than muscle because your body isn’t getting enough building blocks (amino acids) to encourage protein synthesis, a precursor for muscle gain.

For example, if you weigh 200 lbs, that would mean eating 140 to 200 grams of protein daily. A scoop of your average protein powder would provide around 24 grams of protein or 12 to 17% of your protein needs.

Another way to look at the ideal protein intake is to get around 25-30% of your total calories from that nutrient.

Can You Take Both Mass Gainer & Whey Protein When Bulking?

You could decide to take a mass gainer and whey protein together if there are some days when you’re struggling to meet your calorie goals and other days when you find it easier. 

On the days when you’re behind on calories, you could take the mass gainer, but on the days when your calories are naturally higher from food, you could just take the protein powder.

Other than to reach your calorie goals, there probably aren’t many situations when you would need both mass gainer and whey protein because they’re pretty even in regards to their protein content.

Mass Gainer 101

What Is Mass Gainer?

Mass gainers help add mass because they are high in calories, which is crucial. After all, you must eat more calories than your body needs (calorie surplus) to gain weight and build muscle optimally.

Mass gainers have many calories per serving, more carbs than protein, and some fats. This is good because carbs are your body’s preferred fuel source, and fats are energy-dense (nine calories per gram as opposed to four per gram from protein and carbs).

The protein in mass gainers typically comes from whey powder. 

In contrast, carbs typically come from a combination of two sources:

  • Maltodextrin – a processed starch typically derived from corn, wheat, potatoes, and rice
  • Dextrose – a simple carb with a high glycemic index that digests quickly and elevates blood sugar levels; it’s essentially the same as glucose

Finally, fats. 

Here is some insight from Jake Dickson, NASM-CPT:

“While not present in such dense quantities as carbohydrates, the fat content in most mass gainers is markedly higher than standard protein powders, mostly in the form of dairy additives.”

Some dairy additives found in mass gainers include milk fat globule membrane (MFGM), whole milk powder, and cream and butterfat powder.

Benefits of Mass Gainer

benefits of mass gainer

1. Mass Gainer Is High In Calories

One of the main benefits of mass gainers is that they help you gain weight because they’re high in calories.

For example, if you need 3,500 calories but struggle to eat more than 2,600-2,700 from your diet, having a serving of a mass gainer daily on top of that can solve your problem.

2. Mass Gainer Is High In Protein,

Another benefit of a mass gainer is that it has enough protein per serving to help encourage muscle gain, which is important if you want to gain muscle along with fat when you’re bulking up.

The average mass gainer has around 30 to 60 grams of protein per serving, equal to or more than whey protein powder.

If a mass gainer didn’t have a protein component and you weren’t consuming enough protein throughout the day while achieving a calorie surplus, then you’d be much more likely only to put on fat.

3. Mass Gainer Provides Fuel For Training

The calories in the mass gainer come primarily from carbs and fats, which are beneficial for gym performance.

The carbs are beneficial because they’re your body’s preferred energy source, especially when working out, so they’ll provide you with the energy you need to train optimally.

Making the most of your gym workouts can help encourage muscle gain as you gain weight.

I recommend taking your mass gainer pre- or post-workout because this is when the carbs would support performance and recovery the most.

Here is some insight from Elliot Reimers, M.Sc.,:

“Most mass gainers are (significantly) higher in carbs compared to whey protein…Typically, the carbs in mass gainer formulas provide an easily digestible source of energy for high-intensity workouts and muscle recovery.”

Drawbacks of Mass Gainer

drawbacks of mass gainer

1. Mass Gainer May Cause Digestive Issues

Mass gainers are known to cause some digestive issues like bloating, cramping, and diarrhea

There are a few reasons that might happen:

  • It’s too many calories at once. If your body has difficulty digesting this many calories at once, you may experience gas and bloating.
  • It’s too high in fiber. If the mass gainer has a significant amount of fiber, it could overwhelm your digestive system and cause issues.

Also, here is some insight from my colleague and certified nutrition coach Colby Roy:

“Certain ingredients like lactose, gluten, artificial sweeteners, and creatine can be tough for some people to digest and can result in diarrhea,  Taking smaller servings of mass gainer more often throughout the day can help ease the burden on your digestive system.”

If you’re still experiencing digestive discomfort, switching brands of mass gainers may be worth it. 

I recommend looking for one with digestive enzymes, which can help improve digestion. Digestive enzymes to look for include:

2. Mass Gainer Is Often Overused

A mass gainer is often overused because it’s so convenient and serves as a meal replacement for calories and macronutrients. However, the quality and variety of the nutrients aren’t as good as those from whole food.

So if you’re having mass gainer for more than one meal a day, you’re going to be lacking essential micronutrients (vitamins & minerals) your body needs to function optimally.

For the best results, you should only use a mass gainer once daily and focus on getting most of your meals and snacks from whole foods.

How To Pick A High-Quality Mass Gainer?

At FeastGood, we have 9 criteria for ranking mass gainers:

  • Nutrition label transparency – The label should be easy to decipher and have all the ingredients listed.
  • Ingredient quality – The product should have fewer ingredients and come from familiar sources (think whey, coconut sugar, and micellar casein); it should also be free of flavoring and coloring agents, preservatives, and gums.
  • Protein percent of calories – A quality weight gainer will offer at least 15 grams of protein per scoop.
  • Carb-to-protein ratio – The optimal ratio for recovery is around 4-to-1 (e.g., 80 grams of carbs and 20 grams of protein)
  • Taste – While subjective, good taste is also important because it makes it easier and more pleasurable to have a weight gainer as part of your diet
  • Mixability – The product should mix smoothly when blended; bonus points if it mixes well when shaken.
  • Thickness – This is based on preference, as some people prefer a thinner shake that goes down more easily, whereas others prefer a thicker consistency. 
  • Satiety – You don’t want a mass gainer that makes you uncomfortably full, which prevents you from getting additional calories from whole foods later in the day.
  • Cost – Good products generally cost around $0.50 per 100 calories.

Two mass gainer products that cover these criteria are Transparent Labs Mass Gainer and Rival Nutrition Clean Gainer.

Transparent Labs Mass Gainer
Rival Nutrition Clean Gainer

Whey Protein 101

What Is Whey Protein?

Whey protein is a powder supplement you can take if you struggle to consume enough protein. It comes from whey––a clear liquid that’s a byproduct of cheese production.

One unique benefit of whey protein is that it’s rich in cysteine, a non-essential amino acid that’s involved in numerous processes, including making proteins (such as for muscle growth and repair).

Whey protein is lower in calories, carbs, and fats but high in protein, which is why it’s more supportive of lean muscle gain.

To gain muscle without fat, you need to consume enough calories so that your body has the resources to put towards muscle growth, but not so many calories that excess energy is just stored as fat for later use.

Generally speaking, this would be 50 to 200 calories over the number of calories it takes to maintain weight).

Benefits of Whey Protein

benefits of whey protein

1. Whey Protein Is High In Protein

The main benefit of whey protein powder is that it’s very high in protein. Most brands have 20 to 35 grams of protein per scoop.

Protein powder is so convenient because it’s much easier to have a scoop of protein than to eat the equivalent amount of protein from food (examples: 1 cup of Greek yogurt, 4 ounces of chicken breast, 4.5 ounces of steak).

If your goal is to gain muscle, you should eat around 0.7-1 gram of protein per pound of body weight. If you weigh 170 lbs, you should be eating 119-170 grams of protein per day

This could be difficult for those who have a hard time getting enough protein from food sources because they get too full, which is why protein powder can help.

2. Whey Protein Is Best For Maintaining/Gaining Lean Mass

Whey protein helps you more easily get the recommended 1.6-2.2 grams of protein per kilogram, which is necessary for building and maintaining muscle.

That said, whey protein is low in fats and carbs, so it doesn’t provide as many calories as a mass gainer.

So, for optimal results, you also need to get enough calories and additional protein from your diet to maintain a surplus.

Drawbacks of Whey Protein

drawbacks of whey protein

Whey Protein Is Low In Calories

Whey protein is lower in calories, so it may not be the best option for those who want to gain mass at a faster rate or struggle to eat enough food.

How To Pick A High-Quality Whey Protein?

At FeastGood, we have 8 criteria for ranking whey protein powders:

  • Nutrition label transparency – The label should clearly outline the ingredients and their respective quantities.
  • Fat content transparency – There should be information on how much fat the product has per scoop and 100 grams.
  • Effective ingredients – The product should ideally consist of whey isolate (the more refined option with more protein and close to no fats and carbs) and natural sweeteners like stevia. Some products also have leucine peptides, which could further support muscle protein synthesis.
  • Protein percent of calories – A quality protein powder will have 85% or more of the calories coming from protein.
  • Mixability – The product should mix well in a shaker bottle without having to use a blender.
  • Satiety – The product should keep you full for at least a couple of hours, especially if you mix it with milk and add other ingredients like oats or yogurt

Transparent Labs Whey Protein is our #1 pick because it covers all of these criteria.

Frequently Asked Questions

Can Women Also Benefit From Mass Gainers And Whey Protein?

Mass gainers and whey protein powders are ideal for women looking to gain weight and increase their protein intake.

Are There Any Side Effects Of Consuming These Supplements Daily?

Whey protein and mass gainers are safe and suitable for daily consumption, so long as they don’t cause stomach distress and you also eat a rich and varied diet that provides all the nutrients your body needs


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About The Author

Amanda Parker

Amanda Parker is an author, nutrition coach, and Certified Naturopath.  She works with bodybuilders, Olympic weightlifters, and powerlifters to increase performance through nutrition and lifestyle coaching.

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