The Claim
Daily supplementation with 48 μg (1920 IU) of vitamin D3 over 12 weeks of progressive resistance training in healthy young men is associated with a greater increase in type IIa muscle fiber percentage and a reduction in Myostatin mRNA expression compared to a calcium-only placebo, suggesting a potential role for vitamin D in modulating muscle fiber remodeling and protein synthesis regulation.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
Taking a daily vitamin D3 supplement while doing strength training might help young men build more of a certain type of muscle fiber and reduce a protein that limits muscle growth, compared to just taking calcium.
See the scientific wording
Daily supplementation with 48 μg (1920 IU) of vitamin D3 during 12 weeks of progressive resistance training in healthy young men is associated with a greater increase in type IIa muscle fiber percentage and a reduction in Myostatin mRNA expression compared to calcium-only placebo, suggesting a potential role for vitamin D in modulating muscle fiber remodeling and protein synthesis regulation.
What the research says
1 studyThe study gave young men vitamin D3 and had them lift weights, and found that their muscles changed in a way that makes them stronger and more efficient — exactly what the claim said would happen.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.