For the general understanding, mass gainers increase body weight by increasing bodily fat and muscles.

On the other hand, whey protein especially builds muscles. The chemical composition of mass gainers vs. whey protein is tabulated below. The content percentage can vary for different brands.

• Weight Gain: Mass gainers are calorie-rich, mostly containing carbohydrates, fats, and less protein. High calories cause weight gain. Mass gainers can be a perfect staple for individuals with high BMR who struggle with weight gain.
• Stamina enhancement: When combined with resistance exercise, mass gainers can alleviate sarcopenia, especially in older age. ⁽¹⁾

• Fat Gain: High calories and carbohydrates may predispose an individual to weight gain. ⁽²⁾
• Gastric discomfort: Some individuals might experience gastric discomfort and bloating due to high calories in the mass gainers.

• Muscle building: Whey protein contains all nine essential amino acids and is rich in branched chain amino acids which help in muscle building and recovery. ^(3,4)
• Weight loss: Due to less calories, whey protein can assist in weight loss. Moreover, when muscle mass increases, it increase BMR. ⁽⁵⁾
• Add-on: Whey protein can be used as an add-on in several recipes i.e. fruit smoothies, lemon water etc. ⁽⁶⁾

• Bloating: Some people are allergic to protein compounds, which may cause indigestion and discomfort. Whey protein can unusually cause gastric phytobezoar. ⁽⁷⁾

The choice between mass gainers vs. whey protein depends on the health and fitness goals.

• In this scenario, gainers will be better suited for weight gain accompanied by light to medium-resistance exercise.
• Whey protein will be beneficial if you want to achieve body-building goals and maintain muscle mass.

1. Liao, C.-D.; Chen, H.-C.; Huang, S.-W.; Liou, T.-H. The Role of Muscle Mass Gain Following Protein Supplementation Plus Exercise Therapy in Older Adults with Sarcopenia and Frailty Risks: A Systematic Review and Meta-Regression Analysis of Randomized Trials. Nutrients2019, 11, 1713. https://doi.org/10.3390/nu11081713
2. Leaf A, Antonio J. The Effects of Overfeeding on Body Composition: The Role of Macronutrient Composition – A Narrative Review. Int J Exerc Sci. 2017 Dec 1;10(8):1275-1296. doi: 10.70252/HPPF5281. PMID: 29399253; PMCID: PMC5786199.
3. Lopez MJ, Mohiuddin SS. Biochemistry, Essential Amino Acids. [Updated 2024 Apr 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK557845/
4. Duarte NM, Cruz AL, Silva DC, Cruz GM. Intake of whey isolate supplement and muscle mass gains in young healthy adults when combined with resistance training: a blinded randomized clinical trial (pilot study). J Sports Med Phys Fitness. 2020 Jan;60(1):75-84. doi: 10.23736/S0022-4707.19.09741-X. Epub 2019 Sep 23. PMID: 31565912.
5. Frestedt, Joy & Zenk, John & Kuskowski, Michael & Ward, Loren & Bastian, Eric. (2008). A whey-protein supplement increases fat loss and spares lean muscle in obese subjects: A randomized human clinical study. Nutrition & metabolism. 5. 8. 10.1186/1743-7075-5-8.
6. Tlais, A.Z.A.; Trossolo, E.; Tonini, S.; Filannino, P.; Gobbetti, M.; Di Cagno, R. Fermented Whey Ewe’s Milk-Based Fruit Smoothies: Bio-Recycling and Enrichment of Phenolic Compounds and Improvement of Protein Digestibility and Antioxidant Activity. Antioxidants2023, 12, 1091. https://doi.org/10.3390/antiox12051091
7. Klair JS, Girotra M, Dranoff JA, Aduli F. Protein Shakes: An Unusual Cause of Gastric Phytobezoar. ACG Case Rep J. 2015 Jul 9;2(4):196-7. doi: 10.14309/crj.2015.54. PMID: 26203434; PMCID: PMC4508936.