Vitamin D Helps Muscles Get Better at Using Strength, Not Just Getting Bigger
Does vitamin-D intake during resistance training improve the skeletal muscle hypertrophic and strength response in young and elderly men? – a randomized controlled trial
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Taking extra vitamin D while doing leg workouts didn't make muscles bigger or stronger overall, but it helped older men get more strength from each unit of muscle, and helped younger men shift their muscle fibers to a more powerful type.
Surprising Findings
Vitamin D reduced myostatin mRNA in young men—despite no increase in muscle size.
Myostatin is a known muscle growth blocker; lowering it should lead to bigger muscles. But here, it didn’t—suggesting other factors (like training volume or protein intake) may override this signal.
Practical Takeaways
If you’re over 60 and lifting weights, consider 48 mcg (1920 IU) of vitamin D3 daily during training to improve muscle quality and reduce fall risk.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Taking extra vitamin D while doing leg workouts didn't make muscles bigger or stronger overall, but it helped older men get more strength from each unit of muscle, and helped younger men shift their muscle fibers to a more powerful type.
Surprising Findings
Vitamin D reduced myostatin mRNA in young men—despite no increase in muscle size.
Myostatin is a known muscle growth blocker; lowering it should lead to bigger muscles. But here, it didn’t—suggesting other factors (like training volume or protein intake) may override this signal.
Practical Takeaways
If you’re over 60 and lifting weights, consider 48 mcg (1920 IU) of vitamin D3 daily during training to improve muscle quality and reduce fall risk.
Publication
Journal
Nutrition & Metabolism
Year
2015
Authors
J. Agergaard, J. Trøstrup, J. Uth, J. V. Iversen, A. Boesen, J. Andersen, P. Schjerling, H. Langberg
Related Content
Claims (6)
Taking a lot of vitamin D might help your muscles grow bigger by turning down a natural brake that stops them from growing.
When older men lift weights for 12 weeks and take a daily vitamin D3 pill, their muscles get stronger relative to their size compared to men who only take calcium — even though their muscles don’t get bigger or stronger in absolute terms.
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.
Doing strength training for 12 weeks can make your thigh muscles bigger and stronger, whether you're young or old—but taking vitamin D pills won’t make that improvement any better.
Taking vitamin D pills while doing weight training doesn’t change the levels of a specific protein in your muscles that helps vitamin D work, which means vitamin D probably isn’t helping your muscles grow by using this protein.