Vitamin D has recently become one of the most talked-about supplements in health and fitness. Some people swear it improves strength, others claim it builds muscle, and if you've ever searched online, you've probably seen dozens of articles promising both.

But what does the science actually say?

A large meta-analysis published in The Journal of Clinical Endocrinology & Metabolism examined whether taking vitamin D supplements actually improves muscle strength, muscle mass, physical performance, and quality of life. The answer? Lets read on

Vitamin D is often called the "sunshine vitamin" because your body produces it when your skin is exposed to sunlight. For the general population, it is the preferred method of getting this essential vitamin.

It plays several important roles, including:

• Helping your body absorb calcium
• Supporting bone health
• Supporting immune function
• Assisting normal muscle function

Because vitamin D receptors are found in muscle tissue, researchers have wondered whether increasing vitamin D levels could improve strength and athletic performance.

The Study

Instead of looking at just one experiment, researchers combined data from four randomized, placebo-controlled clinical trials. In total, they analyzed more than 400 participants, making this stronger evidence than relying on a single study alone. Participants received either a daily vitamin D3 supplement(s) or a placebo.

Researchers measured:

• Muscle strength
• Muscle mass
• Physical performance
• Quality of life



The intervention lasted between 3 and 9 months.

What they found: a surprisingly simple takeaway

For most people...

Vitamin D supplementation did not significantly improve:

• Muscle strength
• Muscle size
• Physical performance

Or, in other words, If you're already healthy and have adequate vitamin D levels, taking more vitamin D probably won't suddenly make you stronger.

Two interesting points

1. People with Vitamin D deficiency

Participants who started with low vitamin D levels experienced improvements in quality of life after supplementation. Well, that makes sense right? If your body is missing something it needs, replacing it will 9 our of 10 times help. But this doesn't mean people with normal vitamin D levels will experience the same benefits.

2. People with severe obesity

Researchers also found some improvements in muscle strength among participants with severe obesity, but, the exact reason isn't completely understood. It may be because vitamin D is stored in fat tissue, making it less available for the rest of the body. Supplementation may help correct that imbalance. More research is needed before drawing firm conclusions

SO, what does this mean for your fitness goals?

Well, if your goal to build muscle, get stronger, or improve athletic performance, vitamin D should not be viewed as a shortcut. The biggest drivers of muscle growth are still:

• Progressive strength training
• Eating enough protein
• Getting enough calories
• Sleeping well
• Recovering properly

Vitamin D supports your health, but it does not replace those fundamentals.

Vitamin D is an important nutrient for overall health. But despite its popularity in the fitness world, this large review found little evidence that vitamin D supplements improve muscle strength or muscle mass in healthy adults with adequate vitamin D levels.

If you're deficient (spend little time outdoors, live in northern climates or a healthcare provider reommends it), correcting that deficiency is important and may improve how you feel. If you're already sufficient, don't expect vitamin D supplements to replace consistent training, quality nutrition, and good recovery.

Sometimes the biggest improvements don't come from adding another supplement. They come from getting the basics right.

We have the guides, resources, and coaching to help you out! Check out our Coaching Packages where we can give you the tools, the training, and regimen to keep you fit for life.

Blessings and blue skies,

Alexander

Sources

Bislev LS, et al. Effect of Daily Vitamin D3 Supplementation on Muscle Health: An Individual Participant Meta-analysis.The Journal of Clinical Endocrinology & Metabolism. 2022. Researchers concluded that daily vitamin D3 supplementation had no overall effect on muscle strength, muscle mass, or physical performance in the general study population, although some benefits were observed in people with vitamin D deficiency or severe obesity.