A new 36-trial network meta-analysis ranked seven protein sources alongside resistance training. Whey finished first for lean-body-mass gains—but direct trials and newer plant-protein evidence make the real-world answer more interesting than the ranking alone.
In the new network analysis, whey ranked highest for lean-body-mass gain, followed by casein, soy and pea. Whey also had the most convincing statistical evidence versus placebo.
Yet direct trials have shown pea and soy can perform similarly to whey when doses are adequate. For someone cutting to reveal abs, the best powder is ultimately the one that helps consistently hit a high-protein diet while keeping calories and resistance training on track.
Whey’s SUCRA ranking was 0.91, the highest of all protein nodes in that analysis.
Among these four proteins, the lean-mass ranking was clear.
The 2026 Bayesian network meta-analysis included 36 randomized controlled trials, 1,552 participants and 89 trial arms. Every study combined protein supplementation with at least six weeks of supervised resistance training.
Estimated lean-mass difference versus placebo: +1.24 kg.
Estimated lean-mass difference versus placebo: +0.92 kg.
Estimated lean-mass difference versus placebo: +0.55 kg.
Estimated lean-mass difference versus placebo: +0.48 kg.
| Protein | SUCRA rank | LBM vs placebo | 95% credible interval | How confidently should we read it? |
|---|---|---|---|---|
| Whey | 0.91 | +1.24 kg | +0.61 to +1.87 kg | Strongest result of these four, but study-to-study prediction remained wide. |
| Casein | 0.72 | +0.92 kg | +0.18 to +1.66 kg | Credible benefit versus placebo, though ranked below whey. |
| Soy | 0.40 | +0.55 kg | −0.15 to +1.25 kg | Positive point estimate, but the credible interval crossed zero. |
| Pea | 0.35 | +0.48 kg | −0.20 to +1.16 kg | Only a small number of studies informed the network estimate. |
“Whey ranked first” is accurate. “Whey always beats pea and soy” is not.
Network meta-analysis combines direct comparisons with indirect comparisons across a web of studies. That makes it powerful—but its rankings are only as stable as the evidence feeding each node.
Most convincing node
Whey had the highest ranking and an effect estimate whose credible interval excluded zero.
Strong second choice
Casein also showed a statistically credible lean-mass advantage versus placebo.
More uncertainty
Soy’s mean effect was positive, but uncertainty around the estimate was wider.
Thin evidence base
Pea was informed by only three studies in the network, making its rank substantially less secure.
Even for whey, milk and casein, the 95% prediction intervals crossed zero. That means the average result favors supplementation, but a future individual study could plausibly find little or no advantage. The researchers specifically cautioned that the plant-protein evidence was low to very low certainty.
Why whey keeps finishing near the top.
Whey is rapidly digested, rich in essential amino acids and particularly rich in leucine. Those characteristics make it very effective at stimulating muscle protein synthesis after resistance exercise.
Whey produced the largest estimated increase in lean body mass in the new 36-trial network meta-analysis and ranked first for the exploratory strength outcome as well.
The study’s exploratory dose-response model suggested whey benefits began to plateau around this supplemental dose. This should not be confused with a total daily protein target.
Casein ranked below whey—but it may have the best “cutting” personality.
Casein digests more slowly than whey, producing a more prolonged rise in circulating amino acids. In the new network analysis it ranked third overall behind whey and milk, but second among the four proteins in this report.
Casein’s credible interval excluded zero, giving it a more convincing result than soy or pea in this specific long-term network.
Casein’s thicker texture and slower digestion make it a practical evening or high-satiety protein choice for some people dieting on fewer calories.
Direct trials make pea and soy look better than the network ranking alone suggests.
In a 2024 randomized 84-day resistance-training trial, pea and whey produced comparable changes in muscle mass and whole-body strength in healthy sedentary adults.
A randomized trial providing 45 g/day of either a soy-and-pea blend or whey found increases in lean mass, muscle size and leg-press strength in both groups, without significant between-group differences.
Pea can rank surprisingly high when researchers measure the hours after one workout.
A separate 2026 network meta-analysis examined 51 acute studies that measured muscle protein synthesis after resistance exercise and a single protein feeding.
| Protein source | Acute MPS ranking | Interpretation |
|---|---|---|
| Native whey | 0.81 | Highest estimated ranking, though based on limited evidence. |
| Pea protein | 0.77 | Surprisingly high estimated acute response. |
| Whole egg | 0.72 | Also ranked highly. |
| Standard whey | 0.58 | Only standard whey showed a statistically significant effect versus control in the standard network. |
Acute muscle-protein-synthesis research is mechanistically useful, but long-term hypertrophy depends on repeated training, total nutrition, recovery and adherence. A protein source can look excellent over a few hours without automatically producing the highest long-term lean-mass gain.
Which protein gives you the best chance of keeping your abs muscular while calories come down?
During a cut, the job changes slightly. You are no longer simply trying to maximize scale weight or lean-mass gain. You are trying to lose fat while preserving as much muscle, training performance and fullness as practical.
Best all-around choice when you want a high-quality, leucine-rich protein with relatively few calories and an easy post-workout serving.
Particularly attractive for an evening shake, pudding-style snack or anyone who finds slower-digesting protein helps control hunger.
A complete plant protein with direct research showing muscle gains comparable with whey when protein and leucine exposure are adequately matched.
Useful for people avoiding dairy or soy. Direct resistance-training trials have produced outcomes comparable to whey despite the weaker network ranking.
Powder choice is not priority number one.
Your total daily target matters more than whether the tub says whey or pea.
The 2026 International Society of Sports Nutrition position stand on weight reduction provides useful ranges for active people dieting while trying to preserve lean mass.
| Situation | Approximate daily protein range | What it means |
|---|---|---|
| General population losing weight | 1.2–1.6 g/kg/day | Supports weight loss, physical activity and musculoskeletal health. |
| Resistance training / muscle anabolism | 1.6–2.2 g/kg/day | A useful evidence-based range for active lifters seeking to maximize muscle anabolism. |
| Lean, resistance-trained person in a calorie deficit | 1.9–3.2 g/kg/day | Higher intakes may maximize lean-mass retention under more demanding hypocaloric conditions. |
Meat, dairy, eggs, fish, legumes, soy foods, grains and other foods all contribute. A protein supplement is simply a convenient tool for closing the gap between food intake and the desired total.
Which one wins for your actual goal?
| Goal | Whey | Casein | Soy | Pea |
|---|---|---|---|---|
| Best long-term evidence ranking | Winner | Strong | Moderate / uncertain | Limited evidence |
| Post-workout convenience | Excellent | Good | Excellent | Excellent |
| Slow digestion / evening use | Lower | Excellent | Moderate | Moderate |
| Vegan | No | No | Yes | Yes |
| Dairy-free | No | No | Yes | Yes |
| Direct evidence comparable to whey | Reference | Less direct comparison | Yes in some trials | Yes in some trials |
| Best simple default | Whey | Casein if hunger is priority | Soy if vegan | Pea if avoiding dairy/soy |
A premium whey powder cannot rescue a poorly designed cut.
The brand and source matter less when the diet is consistently missing an appropriate overall protein target.
Direct soy and pea comparisons show that adequately dosed plant protein can support excellent resistance-training adaptations.
Network rankings describe probability across studies. They do not predict exactly how many grams of lean tissue one individual will gain.
A supplement meant to preserve muscle can become counterproductive if shakes quietly push total calories high enough to erase the intended deficit.
Whey wins the new ranking. Total protein still wins the bigger argument.
If someone wants one default supplement for resistance training and has no dietary restriction, whey has the strongest case among these four. It ranked first in the new long-term network analysis, has a strong leucine profile and is supported by decades of resistance- training research.
Casein is a close practical alternative—especially during a cut when slower digestion and greater satiety may be useful.
Soy and pea should not be treated as second-rate muscle builders. Their ranking in the new network was lower and less certain, but direct trials show that adequately dosed plant protein can produce muscle and strength adaptations comparable with whey.
For revealing a six-pack, the hierarchy is therefore simple: resistance training first, adequate total daily protein second, sustainable calorie control third—and the precise powder after that.
Sources
- Li J, Qin L, Wang Y, Zhang X. Dose–structure–population interactions of protein supplementation combined with resistance training on body composition: a Bayesian network meta-analysis with dose–response modeling. Frontiers in Nutrition. 2026. PMID: 42625626.
- Impact of different protein sources on acute muscle protein synthesis following resistance training: a systematic review with standard and dose-response network meta-analyses. Journal of the International Society of Sports Nutrition. 2026. PMID: 42862730.
- Singh RG, et al. Efficacy of Pea Protein Supplementation in Combination with a Resistance Training Program on Muscle Performance in a Sedentary Adult Population. Nutrients. 2024. PMID: 38999765.
- Similar effects between animal-based and plant-based protein blend as complementary dietary protein on muscle adaptations to resistance training: findings from a randomized clinical trial. 2025. PMID: 41059835.
- Lynch HM, et al. No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program. International Journal of Environmental Research and Public Health. 2020. PMID: 32486007.
- Yimam M, et al. Long-term effects of plant vs. animal protein supplementation on body composition, muscle strength, physical performance, and cardiometabolic risk factors in adults: a systematic review and meta-analysis of randomized controlled trials. 2026. PMID: 41994089.
- Aragon AA, Campbell BI, Schoenfeld BJ, et al. International Society of Sports Nutrition position stand: diets for body weight reduction. Journal of the International Society of Sports Nutrition. 2026. PMID: 42867412.
- 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. British Journal of Sports Medicine. 2018. PMID: 28698222.
Research reviewed through October 27, 2026. Lean body mass and fat-free mass are not perfect synonyms for newly built contractile muscle; body water, glycogen and measurement method can influence body-composition estimates. Protein requirements vary by body size, energy intake, training load, age and health. This report is general fitness and nutrition information rather than individualized medical nutrition advice.
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