Vitamin DEvidence & Dosage
Serum 25-OH-D, optimal range 40–70 ng/ml, a supplementation strategy.
Evidence at a glance
- Total studies
- 1,000
- With abstract
- 49
- Meta / Systematic / RCT
- 177
- Highly cited
- 50
- Publication years
- 1982–2026
Vitamin D in the context of Vitamins & Minerals
This topic is part of our "Vitamins & Minerals" world. There you'll find methodology, evidence and the highest-impact levers — plus the order in which they sensibly build on each other.
Go to Vitamins & MineralsTop studies on Vitamin D
Ranked by influential-citation count and publication year.
Comparison of vitamin D2 and vitamin D3 supplementation in raising serum 25-hydroxyvitamin D status: a systematic review and meta-analysis.
Am J Clin Nutr2012n=1,016meta200 influential citationsBACKGROUND: Currently, there is a lack of clarity in the literature as to whether there is a definitive difference between the effects of vitamins D2 and D3 in the raising of serum 25-hydroxyvitamin D [25(OH)D]. OBJECTIVE: The objective of…
Finding: This systematic review and meta-analysis found that vitamin D3 supplementation raised serum 25(OH)D concentrations more than vitamin D2 overall.
Effects of vitamin D supplements on bone mineral density: a systematic review and meta-analysis.
Lancet2014n=4,082meta200 influential citationsBACKGROUND: Findings from recent meta-analyses of vitamin D supplementation without co-administration of calcium have not shown fracture prevention, possibly because of insufficient power or inappropriate doses, or because the intervention…
Global and regional prevalence of vitamin D deficiency in population-based studies from 2000 to 2022: A pooled analysis of 7.9 million participants.
Front Nutr2023n=7,947,359systematic200 influential citationsBACKGROUND: Vitamin D deficiency causes the bone hypomineralization disorder osteomalacia in humans and is associated with many non-skeletal disorders. We aim to estimate the global and regional prevalence of vitamin D deficiency in people…
Vitamin D: An overview of vitamin D status and intake in Europe.
Nutrition bulletin2014195 influential citationsIn recent years, there have been reports suggesting a high prevalence of low vitamin D intakes and vitamin D deficiency or inadequate vitamin D status in Europe. Coupled with growing concern about the health risks associated with low…
Vitamin D insufficiency.
Mayo Clin Proc2011review191 influential citationsVitamin D deficiency, which classically manifests as bone disease (either rickets or osteomalacia), is characterized by impaired bone mineralization. More recently, the term vitamin D insufficiency has been used to describe low levels of…
A Systematic Review Supporting the Endocrine Society Clinical Practice Guidelines on Vitamin D.
J Clin Endocrinol Metab2024n=151Systematic Review140 influential citations<h4>Context</h4>Low vitamin D status is common and is associated with various common medical conditions.<h4>Objective</h4>To support the development of the Endocrine Society's Clinical Practice Guideline on Vitamin D for the Prevention of…
High prevalence of vitamin D deficiency in Asia: A systematic review and meta-analysis.
Crit Rev Food Sci Nutr2023n=746,564Meta-Analysis135 influential citationsVitamin D deficiency is a worldwide health problem. However, the prevalence of vitamin D deficiency in Asian populations is unclear. The aims of our study were to investigate the prevalence of vitamin D deficiency and its association with…
The case against ergocalciferol (vitamin D2) as a vitamin supplement.
Am J Clin Nutr2006other112 influential citationsSupplemental vitamin D is available in 2 distinct forms: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Pharmacopoeias have officially regarded these 2 forms as equivalent and interchangeable, yet this presumption of…
Comparison of the Effect of Daily Vitamin D2 and Vitamin D3 Supplementation on Serum 25-Hydroxyvitamin D Concentration (Total 25(OH)D, 25(OH)D2, and 25(OH)D3) and Importance of Body Mass Index: A Systematic Review and Meta-Analysis.
Adv Nutr2024n=20meta89 influential citationsBACKGROUND: Two previous meta-analyses showed smaller differences between vitamin D3 and vitamin D2 in raising serum 25-hydroxyvitamin D [25(OH)D] and a consistently high heterogeneity when only including daily dosing studies. OBJECTIVE:…
Antioxidant vitamins supplementation reduce endometriosis related pelvic pain in humans: a systematic review and meta-analysis.
Reprod Biol Endocrinol2023n=589meta88 influential citationsOBJECTIVE: This study aimed to clarify the effect of antioxidant vitamins supplementation on endometriosis-related pain. METHODS: A systematic search of PubMed, Web of Science, Cochrane Library, Scopus, and China National Knowledge…
Frequently asked
What does the evidence say about Vitamin D?
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Are there safety considerations for Vitamin D?
Related articles
Which supplements actually work? RCT check 2026
Only a handful of supplements show robust effects in randomized trials: creatine monohydrate (3-5 g/day, strength and cognition), omega-3 EPA/DHA (2-4 g/day, triglyceride reduction), magnesium (in deficiency: better sleep quality), vitamin D (when deficient, not prophylactically). Multivitamins, greens powders, and most adaptogens show no relevant effects on hard endpoints in healthy adults.
Which supplement best supports self-optimization?
If you can only choose one: vitamin D3 2000-4000 IU/day — 40-80 % of Central Europeans have suboptimal 25(OH)D levels, supplementation is cheap, safe, and corrects a common deficit. For other goals: creatine (strength+cognition), omega-3 (in elevated triglycerides), magnesium bisglycinate (sleep). 'Best' depends on the deficit, not on marketing.
Vitamin K2 (MK-7): Dosage, D3 Synergy, and the Evidence Base
Vitamin K2 (MK-7) is mainly relevant for bone; the data on blood vessels are mixed. Here, dosage, MK-7 vs. MK-4, and D3 combination are classified clearly.
More topics in Vitamins & Minerals
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Melatonin Optimization
Melatonin needs, dosing (0.3-5 mg), extended-release forms, circadian rhythm, and long-term safety considerations.
Caffeine + L-Theanine
Caffeine, L-Theanine, focus, alertness and tolerance.
NAD+ Precursors
NMN, NR, NAD+, aging biology and evidence landscape.
Omega-3 Fatty Acids
EPA, DHA, ALA: daily needs, sources (fish, algae), Omega-3 index as biomarker, and cardiovascular RCT data.
Vitamin Optimization
Vitamin optimization strategies: needs assessment, bioavailability, synergies, and safety upper limits for the most relevant micronutrients.
Melatonin Signaling
Melatonin as a multi-system hormone: antioxidant, immunomodulatory, mitochondrial, and neuroprotective effects beyond sleep.
Animal vs Human Studies
Mouse ≠ human — translatability from resveratrol to rapamycin is shaky.
Bias
Sponsorship, selection bias, confirmation bias, industry funding.
Cardiovascular System
Blood pressure, heart rate, endothelium, cholesterol, cardiovascular risk factors.
Contraindications
When something must NOT be taken: pregnancy, pre-existing conditions.
Coenzyme Q10 (CoQ10 / Ubiquinol)
Mitochondria, statins, energy, and cardiovascular outcomes.
Correlation vs Causation
The classic misinterpretation of popular health studies.
Curcumin
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Digestive System
Stomach acid, enzymes, absorption, the gut-brain axis, the microbiome.
Effect Size
p-value vs. practical relevance, Cohen's d, confidence intervals.
Ferritin & Iron
Ferritin, transferrin saturation, iron deficiency vs. iron overload.
Glutathione
Master antioxidant, liposomal vs. NAC forms and detoxification.
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