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Protein Supplementation: Animal vs. Plant Protein Sources

animal vs plant protein powder

The role of protein in muscle health and overall well-being cannot be overstated. In the world of nutrition, fitness, and health, a significant debate exists regarding the efficacy of animal versus plant protein sources. In this article we are breaking down the nuances of this debate, exploring the impact of animal vs plant protein sources on muscle strength, lean mass, and the influence of factors like resistance training.

Muscle health is a cornerstone of physical performance, metabolic stability, and overall health. Muscle tissue not only supports movement and strength but also plays a vital role in metabolic functions such as glucose storage and hormone regulation[1]. With aging, there's a natural decline in muscle mass and strength, a condition termed sarcopenia, which has been linked to increased health risks and reduced quality of life[1].

The Nutritional Profile of Protein Sources

Protein sources are broadly categorized into two groups: animal and plant proteins. Animal proteins, including whey, casein, eggs, meat, and dairy products, are characterized by their complete amino acid profiles and high bioavailability[2]. They have been traditionally favored in muscle building due to their comprehensive essential amino acids (EAAs) and efficient stimulation of muscle protein synthesis (MPS). MPS is the biological process where amino acids are assembled into muscle proteins which results in muscle growth and repair.

Plant proteins, derived from sources like soy, peas, rice, and various legumes, have risen in popularity due to lifestyle preferences, such as a vegan and vegetarian diets, and associations with improved cardiovascular health[3]. However, they often lack one or more EAAs and are considered to have lower digestibility, leading to perceptions of inferiority in supporting muscle growth and maintenance compared to animal proteins[4].

To thoroughly understand the impact of these protein sources, we draw upon a broad array of systematic reviews and meta-analyses of randomized controlled trials. These studies offer a comprehensive comparison of the effects of animal and plant proteins on muscle mass and strength.

Effects on Muscle Mass and Strength

An important aspect of the debate is the effect of protein sources on muscle mass and strength. The review of literature reveals that while both animal and plant protein sources can contribute to increases in lean muscle mass, animal proteins exhibit a more pronounced effect on percent lean mass, especially in younger adults[5]. This finding can be attributed to their higher EAA content and digestibility.

Regarding muscle strength, the findings are more complex. No significant difference is observed in muscle strength gains between animal and plant protein sources, indicating that factors beyond protein type, such as exercise routines and overall dietary patterns, are crucial in determining muscle strength[3][5].

Resistance Training and Protein Sources

Resistance training is a well-established enhancer of muscle growth and strength. While the importance of protein in conjunction with resistance training is established, the impact of the protein source (animal vs. plant) in this context has been a subject of extensive research. A meta-analysis by Morton et al[6]., published in the British Journal of Sports Medicine, found that dietary protein supplementation significantly enhanced changes in muscle strength and size during prolonged resistance training in healthy adults. However, the source of protein did not significantly alter these outcomes.

This finding suggests that the type of protein—whether animal-based like whey or casein, or plant-based like soy or pea—may not significantly influence the muscle gains from resistance training. It underscores that the critical factor is the presence of adequate protein, rather than its source, combined with consistent resistance exercise.

Overview of Protein Supplements in the Market

The supplement market today offers a diverse range of protein products, catering to various dietary needs and preferences. These supplements are primarily categorized into animal-based and plant-based proteins, each with unique characteristics and benefits.

Animal Protein Supplements

  1. Whey Protein: Whey protein, a by-product of cheese production, is one of the most popular protein supplements. It's highly favored for its rapid absorption and high concentration of the branched-chain amino acid, leucine[1][7]. Leucine plays a crucial role in initiating muscle protein synthesis, making whey protein a preferred choice for athletes and bodybuilders seeking quick muscle recovery post-exercise. Studies, such as one published by Park et al.,[8] have highlighted whey's effectiveness in promoting muscle growth and recovery.
  2. Casein Protein: In contrast to whey, casein protein, which is also derived from milk, digests more slowly[9]. This slow digestion rate results in a prolonged release of amino acids, making casein an ideal supplement for sustained protein delivery, especially during fasting periods like sleep. Research in the Journal of Nutrition journal[10] suggests that casein's anti-catabolic properties make it beneficial for long-term muscle maintenance.

Plant Protein Supplements

Plant-based protein supplements have undergone significant advancements in recent years. These include:

  1. Soy Protein: Soy protein is one of the most common plant-based protein supplements and is considered a complete protein, providing all essential amino acids. It's a viable option for those following vegetarian or vegan diets. A study but Paul et al.,[11] found that soy protein can be as effective as animal-based proteins in supporting muscle health when consumed in adequate amounts.
  2. Pea and Rice Protein Blends: An evolution in plant-based protein supplements is the combination of different protein sources, such as pea and rice protein, to create a complete amino acid profile. This combination strategy compensates for the limiting amino acids in each protein source. Research from Luc Van Loon’s lab[12] indicates that blends of plant proteins can effectively support muscle repair and growth, similar to their animal counterparts.

Choosing Between Animal and Plant Protein Supplements

The choice between animal and plant protein supplements should be based on individual dietary preferences and tolerances. For example:

  • Dietary Restrictions: Individuals following a vegan diet will prefer plant-based protein supplements like soy, pea, or rice protein.
  • Lactose Intolerance: Individuals who are lactose intolerant may opt for a plant-based protein supplement. However, a 100% whey protein isolate like Build Whey Protein contains nearly zero grams of lactose per serving and is a great choice even for those with lactose intolerance.
  • Muscle Recovery Needs: Athletes and fitness enthusiasts aiming for rapid muscle recovery might prefer whey protein for its quick absorption and high leucine content.
  • Sustained Protein Delivery: Those seeking a sustained release of amino acids, perhaps to prevent muscle breakdown during longer periods without food, might choose casein protein.


In summary, both animal and plant protein sources are effective in supporting muscle health, but they offer different benefits. Animal protein supplements, like whey and casein, might be more efficient in promoting lean muscle mass due to their complete amino acid profiles and high digestibility. Plant protein supplements, such as soy, pea, and rice, have evolved to offer balanced amino acid profiles and are a viable option for those with dietary restrictions. The choice between animal and plant protein should be guided by individual dietary preferences, as both can effectively support muscle strength and overall fitness when combined with resistance training. The key is ensuring adequate and quality protein intake, tailored to personal needs and ethical viewpoints.


Build Whey Protein Powder

Build Whey Protein

Outwork Build contains 100% whey protein isolate with ~3g of leucine per serving to help you recover from hard training and build more muscle. 💪 




1. Argilés, J. M.; Campos, N.; Lopez-Pedrosa, J. M.; Rueda, R.; Rodriguez-Mañas, L. Skeletal Muscle Regulates Metabolism via Interorgan Crosstalk: Roles in Health and Disease. J. Am. Med. Dir. Assoc. 2016, 17 (9), 789–796.

2. Schaafsma, G. The Protein Digestibility-Corrected Amino Acid Score (PDCAAS)--a Concept for Describing Protein Quality in Foods and Food Ingredients: A Critical Review. J. AOAC Int. 2005, 88 (3), 988–994.

3. Lynch, H.; Johnston, C.; Wharton, C. Plant-Based Diets: Considerations for Environmental Impact, Protein Quality, and Exercise Performance. Nutrients 2018, 10 (12), E1841.

4. Pinckaers, P. J.; Domić, J.; Petrick, H. L.; Holwerda, A. M.; Trommelen, J.; Hendriks, F. K.; Houben, L. H.; Goessens, J. P.; van Kranenburg, J. M.; Senden, J. M.; de Groot, L. C.; Verdijk, L. B.; Snijders, T.; van Loon, L. J. Higher Muscle Protein Synthesis Rates Following Ingestion of an Omnivorous Meal Compared with an Isocaloric and Isonitrogenous Vegan Meal in Healthy, Older Adults. J. Nutr. 2023.

5. Lim, M. T.; Pan, B. J.; Toh, D. W. K.; Sutanto, C. N.; Kim, J. E. Animal Protein versus Plant Protein in Supporting Lean Mass and Muscle Strength: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients 2021, 13 (2).

6. Morton, R. W.; Murphy, K. T.; McKellar, S. R.; Schoenfeld, B. J.; Henselmans, M.; Helms, E.; Aragon, A. A.; Devries, M. C.; Banfield, L.; Krieger, J. W.; Phillips, S. M. 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.

7. Norton, L. E.; Layman, D. K. Leucine Regulates Translation Initiation of Protein Synthesis in Skeletal Muscle after Exercise. J. Nutr. 2006, 136 (2), 533S-537S.

8. Park, Y.; Park, H.-Y.; Kim, J.; Hwang, H.; Jung, Y.; Kreider, R.; Lim, K. Effects of Whey Protein Supplementation Prior to, and Following, Resistance Exercise on Body Composition and Training Responses: A Randomized Double-Blind Placebo-Controlled Study. J. Exerc. Nutr. Biochem. 2019, 23 (2), 34.

9. Jäger, R.; Kerksick, C. M.; Campbell, B. I.; Cribb, P. J.; Wells, S. D.; Skwiat, T. M.; Purpura, M.; Ziegenfuss, T. N.; Ferrando, A. A.; Arent, S. M.; Smith-Ryan, A. E.; Stout, J. R.; Arciero, P. J.; Ormsbee, M. J.; Taylor, L. W.; Wilborn, C. D.; Kalman, D. S.; Kreider, R. B.; Willoughby, D. S.; Hoffman, J. R.; Krzykowski, J. L.; Antonio, J. International Society of Sports Nutrition Position Stand: Protein and Exercise. J. Int. Soc. Sports Nutr. 2017, 14 (1), 20.

10. Churchward-Venne, T. A.; Snijders, T.; Linkens, A. M.; Hamer, H. M.; van Kranenburg, J.; van Loon, L. J. Ingestion of Casein in a Milk Matrix Modulates Dietary Protein Digestion and Absorption Kinetics but Does Not Modulate Postprandial Muscle Protein Synthesis in Older Men1, 2, 3. J. Nutr. 2015, 145 (7), 1438–1445.

11. Paul, G.; Mendelson, G. J. Evidence Supports the Use of Soy Protein to Promote Cardiometabolic Health and Muscle Development. J. Am. Coll. Nutr. 2015, 34 Suppl 1, 56–59.

12. Pinckaers, P. J. M.; Trommelen, J.; Snijders, T.; van Loon, L. J. C. The Anabolic Response to Plant-Based Protein Ingestion. Sports Med. 2021, 51 (1), 59–74.

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