Based on 3 first-hand reports and 116 meta-analyses & systematic reviews in the medical literature. Ranked #1620 of 1,974 overall.
Of reports that state an outcome, 0% are positive.
Of the people who reported each effect, the share who said it got better.
Systematic reviews and meta-analyses from PubMed, with their published conclusions.
3+ meta-analyses or systematic reviews and 10+ randomized controlled trials in humans. The grade measures how much human research exists — read the conclusions below for what it found.
Conclusion: Based on absolute risk reductions and thresholds considered clinically meaningful, this review found little to no benefits from use of calcium, vitamin D, or combined supplementation on the prevention of fractures and falls.
PubMed 42161415 ↗Conclusion: In this meta-analysis of randomized clinical trials, the use of supplements that included calcium, vitamin D, or both compared with placebo or no treatment was not associated with a lower risk of fractures among community-dwelling older adults. These findings do not support the routine use of these supplements in community-dwelling older people.
PubMed 29279934 ↗Conclusion: Continuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults without specific risk factors for vitamin D deficiency seems to be inappropriate.
PubMed 24119980 ↗Conclusion: Those with gastrointestinal malabsorption, obesity, or on medications that increase the catabolism of vitamin D and a few other specific disorders require much higher intake. This systematic review evaluates non-classical actions of vitamin D, with particular emphasis on infection and autoimmunity related to the immune system.
PubMed 37686873 ↗As stated by users — not a recommendation. Follow the label or your doctor.
How often each side effect came up across all reports.
Verbatim quotes, shortened only — each links to the original discussion.
“so just eat vitamin D pills, and don't risks getting skin cancer or skin aging (80% of it is due to photodamage) by sun exposure”
“Then we spend heaps on vitamin D supplements, red light devices etc and wonder why we're depressed.”
“Vitamin D supplements are not sunshine and there's so much more that happens in our bodies when sun is on our skin!”
User data from public discussions; research from PubMed. Information only, not medical advice — talk to a doctor before starting, stopping or combining anything. Data updated October 2, 2026. How we rate