The Claim

In older, mobility-limited women with vitamin D insufficiency, daily supplementation with 4000 IU of vitamin D₃ for 4 months increases intramyonuclear vitamin D receptor (VDR) concentration by approximately 30% compared to placebo, suggesting a direct effect of vitamin D on muscle cell signaling.

Source: A randomized study on the effect of vitamin D₃ supplementation on skeletal muscle morphology and vitamin D receptor concentration in older women.

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
61score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

How it works
1 study reviewed
In plain English

For older women who have trouble moving and don’t have enough vitamin D, taking a daily vitamin D pill for four months can boost a key protein inside their muscle cells by about 30%, which might mean vitamin D directly helps muscle cells communicate better.

See the scientific wording

In older, mobility-limited women with vitamin D insufficiency, daily supplementation with 4000 IU of vitamin D₃ for 4 months increases intramyonuclear vitamin D receptor (VDR) concentration by approximately 30% compared to placebo, suggesting a direct effect of vitamin D on muscle cell signaling.

What the research says

1 study
  1. Study: A randomized study on the effect of vitamin D₃ supplementation on skeletal muscle morphology and vitamin D receptor concentration in older women.

    The study gave older women with low vitamin D a daily pill of 4000 IU for 4 months and found their muscle cells increased a key vitamin D receptor by about 30%, just like the claim said.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.