If young guys who lift weights drink a protein shake with 35 grams of casein every day — and keep training — they could gain about 2 to 2.8 kilos of muscle in 10 weeks.
See the scientific wording
In young resistance-trained males, daily consumption of 35 grams of casein protein, as part of a total protein intake of 1.8 g/kg body weight, increases lean soft tissue mass by 2.0–2.8 kg over a 10-week period when combined with a supervised resistance training program.
Very strong evidence
Randomized trialsOne moderate-quality study supports this claim, so treat this as an early signal rather than settled science.
What the research says
1 study reviewedSupporting (1)
Randomized Controlled TrialHuman2018
The study gave young men 35 grams of casein protein every day for 10 weeks while they lifted weights, and they gained about 2 to 2.8 kilograms of muscle, just like the claim says.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting study
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If young guys who lift weights drink a protein shake with 35 grams of casein every day — and keep training — they could gain about 2 to 2.8 kilos of muscle in 10 weeks.
Evidence from Studies
Supporting (1)
Community contributions welcome
Daytime and nighttime casein supplements similarly increase muscle size and strength in response to resistance training earlier in the day: a preliminary investigation
The study gave young men 35 grams of casein protein every day for 10 weeks while they lifted weights, and they gained about 2 to 2.8 kilograms of muscle, just like the claim says.
Contradicting (0)
Community contributions welcome
Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review and Meta-Analysis of Casein Protein Supplementation on Lean Mass in Resistance-Trained Young Men
A systematic review and meta-analysis of double-blind, placebo-controlled RCTs evaluating casein protein (35g/day) on lean soft tissue in young resistance-trained males over 10 weeks, with total protein intake controlled at ~1.8 g/kg/day.
Double-Blind RCT of 35g Daily Casein on Muscle Mass in Young Men Undergoing 10 Weeks of Supervised Resistance Training
A double-blind, placebo-controlled, randomized trial with young resistance-trained males assigned to either 35g/day casein or isocaloric placebo, matched for total protein (1.8 g/kg/day), over 10 weeks of supervised resistance training, measuring lean soft tissue via DEXA.
Prospective Cohort Study of Casein Intake and Lean Mass Changes in Young Men Following Resistance Training Programs
A prospective cohort study tracking young resistance-trained males consuming varying amounts of casein, with detailed dietary and training logs, measuring changes in lean soft tissue over 10 weeks, adjusting for total protein intake and training volume.
Case-Control Study Comparing Casein Intake in Young Men with High vs. Low Lean Mass Gains After 10 Weeks of Resistance Training
A case-control study comparing young resistance-trained males who gained ≥2.0 kg lean mass (cases) versus those who gained less (controls), assessing past casein intake and total protein consumption during a 10-week training period.
Cross-Sectional Analysis of Casein Intake and Lean Body Mass in Young Resistance-Trained Males
A cross-sectional survey and body composition analysis (e.g., DEXA) of young resistance-trained males, assessing current casein intake, total protein, and lean soft tissue mass.