Mass Gainers for Bulking: Are They Worth It?
Mass gainers promise an easy route to size: one shake, more than a thousand calories, and the scale finally moves. For some lifters they genuinely solve a problem; for others they simply add body fat. Our editorial team examined what research says about calorie surpluses and muscle gain, what gainers actually contain, and who is likely to benefit.
What a mass gainer is
A mass gainer is a powdered blend designed to deliver a large number of calories in a single serving. The main ingredients are usually carbohydrates, typically maltodextrin, dextrose or oat flour, combined with protein such as whey concentrate, milk protein or casein, and sometimes added fats.
A serving can range from roughly 400 to more than 1,200 calories depending on the product and the number of scoops. The carbohydrate-to-protein ratio is commonly between 2:1 and 5:1, which distinguishes gainers from standard protein powders.
Many gainers also include creatine, vitamins, minerals, digestive enzymes or medium-chain triglycerides. These additions vary widely in usefulness, and doses are not always meaningful.
| Product type | Calories per serving (approx.) | Protein | Main purpose |
|---|---|---|---|
| Whey protein | 100–150 | 20–30 g | Increase protein intake |
| Lean gainer | 400–600 | 30–40 g | Moderate calorie boost |
| Classic mass gainer | 800–1,300 | 40–60 g | Large calorie surplus |
In the US, gainers are sold as conventional foods or dietary supplements. Their nutritional content is no different in principle from a large meal; the convenience of liquid calories is the main selling point.
How much of a surplus muscle growth needs
Building muscle requires energy. A review by Slater and colleagues (2019) concluded that an energy surplus supports muscle hypertrophy during resistance training, but that larger surpluses mainly increase fat gain rather than proportionally increasing muscle gain.
A study in elite athletes by Garthe and colleagues (2013) compared a nutrition plan providing a surplus of roughly 500 calories per day with self-selected intake. The surplus group gained more lean mass, but also more fat, and the extra muscle gain was more pronounced in some individuals than others.
Iraki and colleagues (2019), in a review of off-season bodybuilding nutrition, suggested aiming for a modest weekly gain of about 0.25 to 0.5 percent of body weight for most trained lifters. Beginners can gain faster, as they build muscle more readily.
Protein needs remain the same with or without a gainer. The ISSN recommends 1.4 to 2.0 grams per kilogram per day for most exercising individuals (Jäger et al., 2017). A gainer helps only if it fills an energy gap that regular meals cannot.
Who benefits from a gainer
Gainers are most useful for people who genuinely struggle to eat enough. This group includes so-called "hardgainers" with small appetites, young athletes with high energy demands, endurance athletes trying to maintain weight during heavy training blocks, and people with very busy schedules.
- Low appetite: liquid calories are easier to consume than large meals.
- High energy expenditure: athletes in heavy training who lose weight unintentionally.
- Limited time: a shake can replace a missed meal on demanding days.
- Weight-class athletes moving up: structured gain under supervision.
For most recreational lifters with normal appetites, a gainer is unnecessary. Adding a meal or snack with whole foods achieves the same surplus with more fiber, micronutrients and satiety.
A practical test is to track intake for a week. If you consistently fall short of your calorie target despite trying to eat more, a gainer may be a reasonable tool. If you meet your target with food, you do not need one.
Downsides and common mistakes
The most common mistake is adding a full-size gainer serving on top of an already adequate diet. That can easily create a surplus of 1,000 calories or more per day, leading to rapid fat gain that later requires a long cutting phase.
Many gainers rely heavily on maltodextrin and sugar. Large, rapid carbohydrate loads can cause blood sugar spikes and, in some people, digestive discomfort, bloating or diarrhea. People with diabetes or insulin resistance should consult a physician or dietitian before using high-carbohydrate gainers.
Gainers made with whey concentrate or milk powders contain lactose, which can be a problem for lactose-intolerant individuals. Added sweeteners, gums and sugar alcohols can also upset sensitive stomachs.
Quality and labeling concerns apply as they do to protein powders. Amino spiking, inaccurate calorie claims and undeclared ingredients have been reported in the supplement market. Athletes in tested sport should choose products certified by independent programs such as NSF Certified for Sport or Informed Sport.
Choosing or building a better shake
If you decide to use a gainer, look at the full label. Prioritize products with at least 30 to 40 grams of protein per serving, a reasonable carbohydrate source such as oat flour, and minimal added sugars. Starting with a half serving lets you control the surplus.
A homemade shake is often cheaper and more nutritious. Blending milk, oats, a banana, peanut butter and a scoop of whey can provide 700 to 900 calories with a balanced mix of protein, carbohydrates, fats and fiber.
Timing is flexible. Many people find it easiest to drink a gainer between meals or after training, when appetite is lower. Drinking it right before a main meal may reduce how much you eat at that meal.
Monitor progress every two to four weeks with body weight, waist measurements, photos and training performance. If weight rises much faster than planned or waist measurements jump, reduce the serving size.
The Editorial Team's Conclusions
Mass gainers are a convenient way to add calories, but they are not necessary for most lifters. Muscle growth requires a modest surplus, not a huge one.
They make the most sense for people with low appetites or very high energy expenditure who cannot reach their calorie targets with food.
Whole-food meals or a homemade shake often provide the same benefit with better nutrition and lower cost. Whatever the source, controlling the size of the surplus is key to limiting fat gain.
To learn more, see our articles on calculating your calorie needs for a bulk, on whey protein for athletes, and on planning a cut after a bulking phase.
References
- Slater GJ, Dieter BP, Marsh DJ, et al. Is an energy surplus required to maximize skeletal muscle hypertrophy associated with resistance training? Front Nutr. 2019;6:131.
- Garthe I, Raastad T, Refsnes PE, Sundgot-Borgen J. Effect of nutritional intervention on body composition and performance in elite athletes. Eur J Sport Sci. 2013;13(3):295–303.
- Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 2019;7(7):154.
- Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. J Int Soc Sports Nutr. 2017;14:20.
- Thomas DT, Erdman KA, Burke LM. American College of Sports Medicine joint position statement: nutrition and athletic performance. Med Sci Sports Exerc. 2016;48(3):543–568.
- Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376–384.
