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If you’re trying to gain weight, you’ll need to consume more calories than you burn on a daily basis.

For those who struggle to eat enough during the day, mass gainer supplements offer a convenient and effective way to boost calorie intake.

Unlike typical protein supplements, mass gainers are rich not only in protein but also in carbs and sometimes in other ingredients, such as healthy fats.

However, some mass gainers are higher-quality than others.

To help you decide what product to buy, we rounded up the best options based on the following criteria:

  • Ingredient and nutritional quality. The products listed below are hand-picked by a registered dietitian based on the quality of their ingredients and nutritional content.
  • Customer reviews. All the products included have mostly favorable reviews.
  • Third-party testing. Most of the supplements listed below are third-party tested for purity and quality.
  • Vetting results. All the products included have been vetted to ensure that they meet Healthline’s medical and business standards.

Here are the 10 best weight and mass gainer supplements of 2021.

Here are the 6 best products if you’re looking for a mass gainer with fewer than 1,000 calories per serving.

Best under 1,000 calories per serving

Transparent Labs Mass Gainer

  • Approximate price per serving: $4.60
  • Largest size available: 6.18 pounds (2.8 kg)
  • Protein source: whey
  • Flavors available: Cookies N Cream, Sweet Vanilla

Transparent Labs is a trusted brand in the supplement industry because all its products are third-party tested by Analytical Resource Laboratories.

Plus, Transparent Labs’ website includes a certificate of analysis for each of its products, allowing you to access third-party test results.

The company’s mass gainer is our overall best pick because it’s made from quality ingredients and is free of artificial preservatives and colors.

It’s also non-GMO verified and sweetened with stevia and monk fruit, both of which are derived from plants.

The Sweet Vanilla flavor is certified gluten-free, but the Cookies N Cream flavor does contain gluten.

Depending on the flavor, one serving contains around 53 grams of 100% grass-fed whey protein, and carb sources include tapioca, oat, and sweet potato, making this one of the most natural products on the list.

Here are the nutrition facts for each 2-scoop (196.8-gram) serving of Transparent Labs Mass Gainer Cookies N Cream:

  • Calories: 790
  • Protein: 53 grams
  • Carbs: 114 grams
  • Fat: 14 grams

Best lower-carb gainer

True Athlete Natural Gainer

  • Approximate price per serving: $2.50
  • Largest size available: 4.78 pounds (2.2 kg)
  • Protein source: whey, casein
  • Flavors available: Chocolate, Vanilla

True Athlete Natural Gainer is a great option if you’re looking to add a smaller number of calories to your day, because it contains just 510 calories per serving.

The product is sweetened naturally with stevia and monk fruit, so if avoiding artificial sweeteners is important to you, this may be a good choice.

With 70 grams of carbs from sources such as buckwheat, quinoa, and oat bran, it’s also the lowest-carb option on our list.

True Athlete is third-party tested by NSF Certified for Sport, meaning it doesn’t contain unsafe levels of contaminants, banned substances, or masking agents and that what’s listed on the label matches what’s actually in the final product.

Here’s the nutrition information for each 4-scoop (135.5-gram) serving of True Athlete Natural Gainer Chocolate:

  • Calories: 510
  • Protein: 35 grams
  • Carbs: 70 grams
  • Fat: 8 grams

Most flavors

Rival Nutrition Clean Gainer

  • Approximate price per serving: $1.11
  • Largest size available: 12 pounds (5.4 kg)
  • Protein source: whey, casein
  • Flavors available: Chocolate Fudge, Soft Serve Vanilla, Cookies and Cream, Chocolate Peanut Butter, Cinnamon Toast Cereal, Campfire Smores

Like True Athlete, Rival Nutrition Clean Gainer is lower in calories and protein, with 560 and 30 grams per serving, respectively.

Of all the products on this list, this one has the most flavor options. Six flavors are available, all sweetened by sucralose and stevia leaf extract.

The supplement also includes healthy fats from flaxseed, avocado, and sunflower powders.

This product carries the Informed Choice seal and is third-party tested by Nutrivo, LLC.

Here are the nutrition facts for each 2-scoop (149-gram) serving of Rival Nutrition Clean Gainer Chocolate Fudge:

  • Calories: 560
  • Protein: 30 grams
  • Carbs: 99 grams
  • Fat: 5 grams

Best affordable under 1,000 calories per serving

Universal Real Gains Weight Gainer

  • Approximate price per serving: $1.73
  • Largest size available: 10.6 pounds (4.8 kg)
  • Protein source: whey, casein
  • Flavors available: Vanilla Ice Cream, Banana

Universal Nutrition has been producing muscle gainer supplements for years.

This product in particular delivers more than 50 grams of high quality protein and 600 calories per serving.

The gainer gets its sweetness from sucralose and acesulfame potassium, so if you prefer to avoid artificial sweeteners, this may not be the best choice for you.

It’s also important to note that the company doesn’t mention whether its products are third-party tested.

Here’s the nutrition information for each 3.5-scoop (155-gram) serving of Universal Real Gains Weight Gainer Vanilla Ice Cream flavor:

  • Calories: 601
  • Protein: 52 grams
  • Carbs: 87 grams
  • Fat: 5 grams

Customer favorite under 1,000 calories per serving

Optimum Nutrition Pro Gainer

  • Approximate price per serving: $2.46
  • Largest size available: 10 pounds (4.5 kg)
  • Protein source: whey, casein, egg
  • Flavors available: Double Rich Chocolate, Banana

Optimum Nutrition produces an award-winning line of supplements that are highly rated by consumers.

Optimum Nutrition Pro Gainer contains a whopping 60 grams of dairy and egg protein — both of which are considered high quality proteins.

Like Universal Real Gains, it’s sweetened with sucralose and acesulfame potassium.

Optimum Nutrition products carry the Informed Choice seal and are Certified for Sport by NSF International, which means they don’t contain any banned substances.

Additionally, Optimum Nutrition’s facility meets Food and Drug Administration standards for current Good Manufacturing Practice (cGMP) regulations.

Here are the nutrition facts for each 1-scoop (165-gram) serving of Optimum Nutrition Pro Gainer Double Rich Chocolate:

  • Calories: 650
  • Protein: 60 grams
  • Carbs: 85 grams
  • Fat: 8 grams

Best with creatine

MuscleMeds Carnivor Mass

  • Approximate price per serving: $2.32
  • Largest size available: 10.5 pounds (5.8 kg)
  • Protein source: beef
  • Flavors available: Vanilla Caramel, Chocolate Fudge, Chocolate Peanut Butter, Strawberry

While most protein supplements rely on dairy proteins such as whey and casein, MuscleMeds Carnivor Mass uses protein isolated from beef.

Not only is this product made with a unique protein source, but it also contains 5 grams of added creatine monohydrate.

Creatine is known to be one of the most effective supplements for improving muscular strength and power (1).

While creatine supplements are relatively inexpensive on their own, those who want both a mass gainer and creatine may find a combined supplement like this one convenient.

Like the above products, this gainer is sweetened with artificial sweeteners, sucralose and acesulfame potassium.

MuscleMeds Carnivor Mass is third-party certified by Informed Choice, so you can trust the quality of its ingredients.

Here are the nutrition facts for each 4-scoop (192-gram) serving of MuscleMeds Carnivor Mass Chocolate Peanut Butter:

  • Calories: 710
  • Protein: 50 grams
  • Carbs: 125 grams
  • Fat: 2 grams

If you have a tough time gaining weight and are considering a mass gainer supplement, you might want a higher-calorie option.

Here are the top 4 mass gainers that boast more than 1,000 calories per serving.

Best affordable over 1,000 calories per serving

Optimum Nutrition Serious Mass

  • Approximate price per serving: $2.71
  • Largest size available: 12 pounds (5.4 kg)
  • Protein source: whey, casein, egg
  • Flavors available: Chocolate, Banana, Chocolate Peanut Butter

Optimum Nutrition Serious Mass has almost twice as many calories per serving as its lower-calorie counterpart.

Just like the company’s Pro Gainer, this supplement has been third-party tested and carries the Informed Choice seal. It’s also Certified for Sport by NSF International.

As with nearly all other mass gainers, the calories come primarily from carbs — and this product has more than 250 grams of carbs per serving.

There are three flavors to choose from, all of which are sweetened with acesulfame potassium.

Here’s the nutrition information for each 2-scoop (336-gram) serving of Optimum Nutrition Serious Mass Chocolate:

  • Calories: 1,250
  • Protein: 50 grams
  • Carbs: 252 grams
  • Fat: 4.5 grams

Best with vegan options

Naked Nutrition Naked Mass

  • Approximate price per serving: $5.90
  • Largest size available: 8 pounds (3.63 kg)
  • Protein source: pea, brown rice
  • Flavors available: Unflavored, Chocolate, Vanilla, Vegan Unflavored, Vegan Chocolate, Vegan Vanilla

Naked Nutrition is known for producing high quality products with short ingredient lists.

All the company’s supplements are third-party tested by Eurofins Scientific and manufactured in cGMP-certified facilities.

Additionally, all the flavors of this mass gainer are certified gluten-free, GMO-free, and soy-free.

One of the standout features of this product is the option to buy both vegan and unflavored powders.

Plus, unlike others on this list, the flavored varieties of this product are sweetened naturally with coconut sugar.

The vegan mass gainers contain pea and brown rice protein, while the nonvegan gainers get their protein from whey and casein.

Both the vegan and the nonvegan products contain 50 grams of protein and more than 1,000 calories per serving.

Here are the nutrition facts for each 4-scoop (315-gram) serving of Naked Mass Vegan Unflavored:

  • Calories: 1,230
  • Protein: 50 grams
  • Carbs: 248 grams
  • Fat: 4 grams

Customer favorite over 1,000 calories per serving

Dymatize Super Mass Gainer

  • Approximate price per serving: $2.82
  • Largest size available: 12 pounds (5.4 kg)
  • Protein source: whey, casein, egg
  • Flavors available: Gourmet Vanilla, Chocolate Cake Batter, Cookies & Cream

Dymatize Super Mass Gainer has more than 5,000 5-star reviews online and is third-party tested by Informed Choice to ensure quality and purity.

While it contains 1 gram of creatine monohydrate per serving, this dose may be lower than needed for maximum benefits, so you may want to consider an additional creatine supplement.

Like many other mass gainers on the market, this product gets its sweetness from acesulfame potassium and sucralose.

Here’s the nutrition information for each 2.5-cup (333-gram) serving of Dymatize Super Mass Gainer Gourmet Vanilla:

  • Calories: 1,280
  • Protein: 52 grams
  • Carbs: 246 grams
  • Fat: 9 grams

Best high calorie gainer for competitive sports

MusclePharm Combat XL

  • Approximate price per serving: $3.50
  • Largest size available: 12 pounds (5.4 kg)
  • Protein source: whey, casein
  • Flavors available: Vanilla, Chocolate Milk, Chocolate Peanut Butter

Banned substance tested and certified by Informed Choice, MusclePharm Combat XL is a great option for competitive athletes because both the supplement’s manufacturing process and its actual contents have been tested for substances banned in sports.

The gainer is available in three flavors, all of which are sweetened with acesulfame potassium and sucralose.

Because the powder tends to clump, customers recommend using a blender to ensure a smooth consistency.

Here are the nutrition facts for each 4-scoop (332-gram) serving of MusclePharm Combat XL Chocolate:

  • Calories: 1,270
  • Protein: 50 grams
  • Carbs: 252 grams
  • Fat: 7 grams

When looking for a gainer supplement, there are a few things to consider.

First, it’s best to choose a product that has been third-party tested to ensure you’re getting the best quality.

Some well known third-party testing organizations are:

  • NSF International
  • Informed Choice
  • Eurofins Scientific
  • Analytical Resource Laboratories
  • USP

Additionally, it’s a good idea to consider your goals and how many extra calories you’re looking to add to your day, because the products listed above vary from 510 to 1,360 calories per serving.

Another important consideration is the serving size. While some powders are more concentrated, others require you to add up to 4 scoops of power per serving.

If having a natural product is important to you, you may want to opt for one that is sweetened with stevia or natural sugar rather than artificial sweeteners such as sucralose and acesulfame potassium.

On a similar note, there are plant-based products available, so if you prefer to avoid dairy or animal products, be sure to choose a vegan mass gainer.

If you’re having trouble gaining weight, you may not be consuming enough calories.

While it’s possible to meet your calorie needs through food alone, some people find mass gainer supplements helpful for achieving their weight goals.

To find the product that’s right for you, you’ll want to consider a variety of factors, including nutritional quality, serving size, available flavors, and third-party testing.

We also recommend talking with a healthcare professional before adding a new supplement to your daily routine.