Researchers combined results from seven studies to see if vitamin D supplements help people over 60 build muscle and get stronger. They found that vitamin D didn’t help people gain muscle or grip strength, but it might have helped reduce body fat slightly. The studies included older adults with low vitamin D levels who took supplements for 3 to 36 months. While the results are interesting, scientists say more research is needed to fully understand how vitamin D affects older bodies.

The Quick Take

  • What they studied: Whether taking vitamin D supplements helps older adults (age 60+) build muscle, gain strength, and lose fat
  • Who participated: Seven different research studies involving 50 to 1,094 older adults per study, with an average age between 60 and 74 years. All participants started with low vitamin D levels in their blood
  • Key finding: Vitamin D supplements did not help older adults build muscle or increase grip strength. However, there was a small hint that vitamin D might help reduce body fat, though this finding needs more research to confirm
  • What it means for you: If you’re an older adult hoping vitamin D alone will help you build muscle and get stronger, this research suggests it probably won’t. However, vitamin D is still important for bone health and other body functions. Talk to your doctor about whether you need vitamin D supplements for overall health, not just for building muscle

The Research Details

Scientists searched three major medical databases for high-quality studies testing vitamin D in older adults. They only included randomized controlled trials, which are the gold standard in research because they randomly assign people to either take vitamin D or a placebo (fake pill). This random assignment helps ensure fair comparisons. The researchers looked at seven studies that measured muscle mass, body fat, and grip strength in older adults who took vitamin D for anywhere from 3 months to 3 years.

The studies they reviewed included older adults with low starting vitamin D levels (between 15 and 33 ng/mL, which is considered deficient). Some studies used regular vitamin D supplements, while others used a special form called active vitamin D. The researchers analyzed the results separately to see if the type of vitamin D made a difference.

By combining results from multiple studies, researchers can see the bigger picture instead of relying on just one study. This approach is stronger because individual studies can have different results due to chance or small differences in how they were done. A meta-analysis helps answer the question: ‘What does all the evidence together tell us?’ This is especially important for older adults because muscle loss is a real health problem that affects independence and quality of life.

This meta-analysis is reliable because it only included randomized controlled trials, which are considered the most trustworthy type of research. The studies were fairly large (ranging from 50 to over 1,000 participants) and lasted long enough to see real changes (3 months to 3 years). However, the number of studies was small (only seven), and they varied in how they measured results and how much vitamin D they gave people. This variation makes it harder to draw firm conclusions.

What the Results Show

The main finding was clear: vitamin D supplements did not help older adults build muscle mass or increase their grip strength. When researchers looked at muscle mass specifically (measured as skeletal muscle mass index), the vitamin D group showed no significant improvement compared to the control group. Similarly, handgrip strength—a simple test of overall strength—did not improve with vitamin D supplements.

The one possible positive finding was a small decrease in body fat in the vitamin D group. However, this finding was modest and the researchers noted it needs more research to confirm it’s real and meaningful. When they excluded studies using the special ‘active’ form of vitamin D and only looked at regular vitamin D supplements, even this small fat loss benefit disappeared.

The studies lasted between 3 months and 3 years, so the researchers had enough time to observe changes. The participants started with low vitamin D levels, which means they were the type of people who might benefit most from supplementation. Despite this, vitamin D alone did not produce the muscle-building effects some people hope for.

When researchers separated the analysis by type of vitamin D used, they found that regular vitamin D (the kind most people take) showed no benefits for muscle, strength, or fat loss. The studies using active vitamin D (a prescription form) also showed no improvement in muscle mass or strength. This suggests that the form of vitamin D doesn’t change the main conclusion. The studies measured outcomes at different time points, but even the longer studies (up to 3 years) didn’t show muscle-building benefits from vitamin D alone.

Previous research has suggested that vitamin D might help with muscle function, which is why this question is important. However, this comprehensive review of the best available evidence suggests that vitamin D supplements alone—without other interventions like exercise or protein intake—don’t significantly improve muscle mass or strength in older adults. This doesn’t mean vitamin D is useless; it remains important for bone health, immune function, and other body processes. It simply means that if your goal is to build muscle and strength, vitamin D alone probably isn’t enough.

The main limitation is that only seven studies met the criteria for inclusion, which is a relatively small number. The studies varied in important ways: some lasted 3 months while others lasted 3 years, some gave different doses of vitamin D, and they measured results using slightly different methods. This variation makes it harder to combine the results confidently. Additionally, most studies didn’t look at whether exercise or protein intake (which are known to help build muscle) affected the results. The studies also didn’t always report all the information researchers needed, which limited the analysis. Finally, most participants were from developed countries, so the results might not apply to all older adults worldwide.

The Bottom Line

Based on this research, vitamin D supplements alone are not recommended as a strategy to build muscle or increase strength in older adults (moderate confidence level). However, vitamin D remains important for overall health, especially bone health. If you’re deficient in vitamin D (which many older adults are), your doctor may recommend supplements for general health reasons. To build muscle and strength, the evidence strongly supports combining vitamin D (if deficient) with regular exercise, especially strength training, and adequate protein intake. These combined approaches are much more effective than vitamin D alone.

This research is most relevant to older adults (60+) who are considering vitamin D supplements specifically to build muscle or increase strength. It’s also important for doctors and health professionals advising older patients. If you have low vitamin D levels, you should still consider supplementation for bone health and overall wellness, but don’t expect it to build muscle on its own. People with certain medical conditions affecting vitamin D absorption or metabolism should discuss supplementation with their doctor, as they may benefit differently.

If you start taking vitamin D supplements, don’t expect to see muscle growth or strength improvements within weeks or even months. The studies reviewed lasted 3 months to 3 years, and even with that much time, vitamin D alone didn’t produce these benefits. However, vitamin D’s benefits for bone health and immune function may take several months to become apparent. If you want to build muscle and strength, combine vitamin D (if needed) with regular strength training and adequate protein—you should start noticing strength improvements within 4-8 weeks of consistent exercise.

Want to Apply This Research?

  • Track your vitamin D intake (in IU or micrograms) daily and measure grip strength monthly using a hand dynamometer or by noting how easily you can open jars and carry groceries. Also track body weight and waist circumference weekly to monitor body composition changes
  • If you’re deficient in vitamin D, set a daily reminder to take your supplement at the same time each day (perhaps with breakfast). More importantly, add 2-3 days per week of strength training exercises to your routine—this combination is what actually builds muscle in older adults
  • Create a monthly check-in where you record grip strength, body weight, and how you feel physically (energy level, ability to do daily activities). Track your vitamin D supplement adherence daily. After 3 months, review whether you’ve added strength training to your routine, as this is the key factor for building muscle, not vitamin D alone

This research summary is for educational purposes only and should not replace professional medical advice. Vitamin D supplementation decisions should be made in consultation with your healthcare provider, who can assess your individual vitamin D levels, overall health status, and medical history. This meta-analysis shows vitamin D alone doesn’t build muscle, but vitamin D may still be important for your bone health and overall wellness. If you’re considering starting supplements or changing your current regimen, please discuss it with your doctor first. This information is current as of the publication date but medical understanding evolves as new research emerges.