The Study
Muscle-Related Effect of Whey Protein and Vitamin D3 Supplementation Provided before or after Bedtime in Males Undergoing Resistance Training
This study is like a fair test where people were randomly split into groups to see if a special drink (with protein and vitamin D) helps build muscle when working out. Because it was a fair test, we can say the drink probably helped, but we don’t know if it was the protein, the vitamin D, or both working together.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Young guys who were low on vitamin D did strength training and took a drink with protein and vitamin D either at night or in the morning. Another group took a fake drink. After 6 weeks, the ones who took the real drink gained more muscle and had better hormone levels, no matter when they took it.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 554 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, the gains are meaningful—over 1.5 kg of muscle in just 6 weeks is substantial for untrained individuals, especially since the control group didn’t gain muscle despite training.
- 2- Muscle gain: 1.5–1.8 kg more lean mass
- 3- Leg muscle gain: +0.6 kg
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2022
Authors
Yan Chen, Yiheng Liang, Hang Guo, Kun Meng, Junqiang Qiu, D. Benardot
Related Content
Claims (6)
If you're getting the same amount of protein every day, it doesn't matter whether you drink a shake before bed or at another time — you'll gain the same amount of muscle and strength.
If young guys who don’t have enough vitamin D take 4000 IU of vitamin D and 25 grams of whey protein every day while doing strength training for six weeks, their vitamin D levels go up enough to get into a healthy range.
If young guys who don't get enough vitamin D lift weights and take a daily combo of whey protein and a high dose of vitamin D, they'll gain more muscle — especially in their legs — than those who just lift weights without the supplements.
If young guys who don't get enough vitamin D are working out with weights, taking a protein and vitamin D supplement at night or in the morning works just as well for building muscle and improving body shape — it doesn't matter what time they take it.
If young guys who don't have enough vitamin D lift weights and also take a combo of whey protein and a high dose of vitamin D every day for six weeks, their body's muscle-building hormones go up and muscle-limiting hormones go down—better than just lifting weights alone.
If young guys who don’t have enough vitamin D do strength training without taking extra protein or vitamin D, they can get stronger legs—but their muscles won’t grow much, and their muscle hormones won’t change.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.