Vitamin D

vitamin
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Vitamin D is a fat-soluble nutrient that helps maintain calcium and phosphate levels, which are essential for forming and maintaining strong bones and teeth. It also plays a role in supporting cell growth, neuromuscular function, and a healthy inflammatory response. The body can produce this vitamin when skin is exposed to UVB rays from sunlight, though it is also found in fatty fish and fortified foods. Once consumed or produced, it is converted into its active form primarily in the kidneys, a process that is supported by nutrients like magnesium. In its active state, it acts similarly to a hormone to influence various physiological processes. Beyond its role in skeletal health, this nutrient is often used to support immune system modulation, cardiovascular health, and mood regulation. Maintaining adequate levels is associated with better general well-being and supports many systems throughout the body.

Natural sources
Sunlight exposure (UVB)Fatty fish (salmon, mackerel, tuna)Cod liver oilFortified dairy products (milk, yogurt)Fortified cerealsEgg yolksMushrooms (especially those exposed to UV light)

Ingredient forms

No public comparison lists found.

Timing & Intake
AnytimePreferred: MorningWith foodTake with A meal containing fats for optimal absorption, especially beneficial with Magnesium, Calcium, and Vitamin K.
Since this vitamin is fat-soluble, taking it with a meal containing some fat may help improve absorption. While many people prefer taking it in the morning for consistency, it can be taken at any time of day.
Daily Intake
RDA (Men)600 IU
RDA (Women)600 IU
RDI800 IU
Optimal Dosage
Minimum2000 IU
Maximum4000 IU
Safety & Toxicity
Upper Limit (UL)4000 IU
Toxicity Threshold10000 IU
Toxicity Effecthypercalcemia, kidney stones
4 safety notes
  • Do not exceed recommended doses, as excessive intake can lead to Vitamin D toxicity (hypercalcemia).
  • Individuals with pre-existing kidney disease, sarcoidosis, or hyperparathyroidism should consult a healthcare professional before supplementing.
  • Monitor Vitamin D levels with a blood test if taking high doses or if concerns about deficiency/excess exist.
  • Pregnant or breastfeeding individuals should consult a healthcare professional.
Goals
Anti-Aging
Anti-Aging
Impact
Highest effect
Typical dose:1000–4000 IU
Vitamin D deficiency is linked to osteoporosis, a weakened immune system (immunosenescence), and cognitive decline. Supplementation is one of the most effective ways to maintain adequate levels, supporting calcium absorption for strong bones and modulating immune responses.

Study evidence

50 studies

Low Vitamin D levels are associated with several signs of less healthy aging, but these links do not prove that supplements slow aging. Preliminary findings on biological-age markers are encouraging, especially in deficiency, while clear benefits for longevity or broad age-related function remain unestablished.

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Anti-Inflammatory Support
Anti-Inflammatory Support
Impact
Highest effect
Typical dose:1000–4000 IU
Vitamin D deficiency is strongly correlated with increased systemic inflammation and autoimmune conditions. It helps calm overactive immune cells and reduces the expression of pro-inflammatory messengers. Maintaining adequate levels is essential for keeping the body's inflammatory baseline in check.

Study evidence

101 studies

Vitamin D may reduce selected inflammation markers in some people with deficiency or inflammatory illness, but it does not consistently reduce inflammation. The available research does not establish routine supplementation as a general anti-inflammatory treatment, even when blood vitamin D levels rise.

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Bone Health
Bone Health
Impact
Highest effect
Typical dose:20–100 mcg
Without sufficient Vitamin D, the body cannot effectively absorb calcium from the diet, rendering calcium intake less effective. It is a critical hormone-like vitamin that directly regulates calcium and phosphorus homeostasis, which is fundamental to bone mineralization and maintaining density.

Study evidence

202 studies

Vitamin D is essential for bone mineralization, but extra supplementation does not reliably strengthen bones in people with adequate status. The clearest supplied fracture benefits involve Vitamin D combined with calcium in older adults; high-dose supplementation can reduce bone density.

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Brain Health
Brain Health
Impact
Highest effect
Typical dose:1000–4000 IU
Vitamin D receptors are widely distributed throughout the brain, where it helps regulate the synthesis of neurotransmitters and supports nerve growth. Correcting common deficiencies is linked to improved mood and cognitive performance, as well as reduced risk of age-related cognitive decline.

Study evidence

94 studies

Low Vitamin D levels are associated with poorer cognition and greater dementia risk, but supplementation has not reliably improved brain health. Some pooled analyses and trials report cognitive benefits, while substantial controlled research remains negative, including in adults with mild to moderate deficiency.

View goal
Cardiovascular Support
Cardiovascular Support
Impact
Highest effect
Typical dose:1000–4000 IU
Widespread deficiency and strong links to hypertension, inflammation, and endothelial dysfunction make Vitamin D a critical, foundational supplement.

Study evidence

170 studies

Vitamin D may modestly improve some cardiovascular risk markers in selected populations, but results are inconsistent and do not establish broad heart protection. Low vitamin D is associated with poorer cardiovascular health, yet supplementation has not reliably reduced major cardiovascular events.

View goal
Cognitive Support
Cognitive Support
Impact
Highest effect
Typical dose:1000–5000 IU
Vitamin D deficiency is widespread and has a profound negative impact on cognition. As a critical neuro-regulatory hormone, its importance is foundational, similar to Magnesium and B12.

Study evidence

118 studies

Low Vitamin D levels are often associated with poorer cognition, but supplementation has not consistently improved thinking or prevented dementia in controlled research. Some benefits appear in selected populations, while a dependable cognitive benefit for people with adequate Vitamin D remains unestablished.

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Showing 6 of 25 goals

Studies

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Sources

Up to five highest-ranked published examples per goal. Study counts and charts include all published studies for the connection.

  1. Joint association of serum 25-hydroxyvitamin D concentration and body mass index on the acceleration of clinical biomarker-based biological aging.
    Pan Z; Zeng J; Chen Z; Chen S; Yang J; Li H; Wang S; Wang J; Li N; Gong Y; Liu M; Li C · The journals of gerontology. Series A, Biological sciences and medical sciences · 2026
    Cohort study389,217 participantsAnti-Aging
  2. Serum 25-Hydroxyvitamin D Levels as an Aging Marker: Strong Associations With Age and All-Cause Mortality Independent From Telomere Length, Epigenetic Age Acceleration, and 8-Isoprostane Levels.
    Schöttker B; Hagen L; Zhang Y; Gào X; Holleczek B; Gao X; Brenner H · The journals of gerontology. Series A, Biological sciences and medical sciences · 2019
    Cohort study9,940 participantsAnti-Aging
  3. Sex-specific associations of serum 25-hydroxyvitamin D concentrations with incident sarcopenia in older adults: A 2-year follow-up study.
    Song S; Lim JY; Kim M; Won CW; Park HY · The journal of nutrition, health & aging · 2025
    Cohort study1,292 participantsAnti-Aging
  4. Vitamin D deficit is associated with accelerated brain aging in the general population.
    Terock J; Bonk S; Frenzel S; Wittfeld K; Garvert L; Hosten N; Nauck M; Völzke H; Van der Auwera S; Grabe HJ · Psychiatry research. Neuroimaging · 2022
    Cross-sectional study1,865 participantsAnti-Aging
  5. Vitamin D intake is associated with dementia risk in the Washington Heights-Inwood Columbia Aging Project (WHICAP).
    Zhao C; Tsapanou A; Manly J; Schupf N; Brickman AM; Gu Y · Alzheimer's & dementia : the journal of the Alzheimer's Association · 2021
    Cohort study1,759 participantsAnti-Aging
  6. Vitamin D deficiency and C-reactive protein: a bidirectional Mendelian randomization study.
    Zhou A; Hyppönen E · International journal of epidemiology · 2023
    Observational study294,970 participantsAnti-Inflammatory Support
  7. Vitamin D in Children With Inflammatory Bowel Disease: A Randomized Controlled Clinical Trial.
    El Amrousy D; El Ashry H; Hodeib H; Hassan S · Journal of clinical gastroenterology · 2021
    Randomized trial120 participantsAnti-Inflammatory Support
  8. Vitamin D supplementation reduces infection rate and promotes wound healing in patients with diabetic foot ulcers.
    Gao YQ; Gao YH; Xing JH · World journal of diabetes · 2025
    Randomized trial120 participantsAnti-Inflammatory Support
  9. Associations of C-reactive Protein with 25-hydroxyvitamin D in 24 Specific Diseases: A Cross-sectional Study from NHANES.
    Yang F; Sun M; Sun C; Li J; Yang X; Bi C; Wang M; Pu L; Wang J; Wang C; Xie M; Yao Y; Jin L · Scientific reports · 2020
    Cross-sectional study9,809 participantsAnti-Inflammatory Support
  10. Combined effects of vitamin D deficiency and systemic inflammation on all-cause mortality and cause-specific mortality in older adults.
    Zhang C; Cui J; Li S; Shen J; Luo X; Yao Y; Shi H · BMC geriatrics · 2024
    Cohort study3,072 participantsAnti-Inflammatory Support
  11. Pregnancy vitamin D supplementation and offspring bone mineral density in childhood follow-up of a randomized controlled trial.
    Moon RJ; D' Angelo S; Curtis EM; Ward KA; Crozier SR; Schoenmakers I; Javaid MK; Bishop NJ; Godfrey KM; Cooper C; Harvey NC; MAVIDOS Trial Group · The American journal of clinical nutrition · 2024
    Randomized trial454 participantsBone Health
  12. Vitamin D analogs and bone: preclinical and clinical studies with eldecalcitol.
    Matsumoto T; Takano T; Saito H; Takahashi F · BoneKEy reports · 2014
    Narrative reviewBone Health
  13. Efficacy of vitamin D fortified foods on bone mineral density and serum bone biomarkers: A systematic review and meta-analysis of interventional studies.
    Tangestani H; Djafarian K; Emamat H; Arabzadegan N; Shab-Bidar S · Critical reviews in food science and nutrition · 2020
    Meta-analysis1,786 participants20 studies pooledBone Health
  14. Cholecalciferol Supplementation Attenuates Bone Loss in Incident Kidney Transplant Recipients: A Prespecified Secondary Endpoint Analysis of a Randomized Controlled Trial.
    Tsujita M; Doi Y; Obi Y; Hamano T; Tomosugi T; Futamura K; Okada M; Hiramitsu T; Goto N; Isaka Y; Takeda A; Narumi S; Watarai Y · Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research · 2022
    Randomized trial193 participantsBone Health
  15. Vitamin D supplementation and bone health in post-menopausal women: a 24-month randomized controlled intervention with enhanced bioavailability formulations.
    Rasool N; Munir Y · European journal of clinical nutrition · 2026
    Randomized trial612 participantsBone Health
  16. Vitamin D and brain health: an observational and Mendelian randomization study.
    Navale SS; Mulugeta A; Zhou A; Llewellyn DJ; Hyppönen E · The American journal of clinical nutrition · 2022
    Cohort study427,690 participantsBrain Health
  17. The association between vitamin D and cognition: a systematic review.
    van der Schaft J; Koek HL; Dijkstra E; Verhaar HJ; van der Schouw YT; Emmelot-Vonk MH · Ageing research reviews · 2014
    Systematic review28 studies pooledBrain Health
  18. Vitamin D Status and Rates of Cognitive Decline in a Multiethnic Cohort of Older Adults.
    Miller JW; Harvey DJ; Beckett LA; Green R; Farias ST; Reed BR; Olichney JM; Mungas DM; DeCarli C · JAMA neurology · 2016
    Cohort study382 participantsBrain Health
  19. Vitamin D insufficiency and cognitive impairment in Asians: a multi-ethnic population-based study and meta-analysis.
    Annweiler C; Milea D; Whitson HE; Cheng CY; Wong TY; Ikram MK; Lamoureux EL; Sabanayagam C · Journal of internal medicine · 2017
    Meta-analysis2,273 participants7 studies pooledBrain Health
  20. Vitamin D status predicts new brain magnetic resonance imaging activity in multiple sclerosis.
    Mowry EM; Waubant E; McCulloch CE; Okuda DT; Evangelista AA; Lincoln RR; Gourraud PA; Brenneman D; Owen MC; Qualley P; Bucci M; Hauser SL; Pelletier D · Annals of neurology · 2012
    Cohort study469 participantsBrain Health
  21. Comparative Efficacy of Nutraceuticals on Endothelial Function: A Systematic Review and Network Meta-Analysis.
    Norouzzadeh M; Rashedi MH; Mahdavi-Mazdeh G; Kosari A; Shahinfar H · Current atherosclerosis reports · 2026
    Meta-analysisCardiovascular SupportHeart Health
  22. A Randomized Trial of Vitamin D Supplementation on Vascular Function in CKD.
    Kumar V; Yadav AK; Lal A; Kumar V; Singhal M; Billot L; Gupta KL; Banerjee D; Jha V · Journal of the American Society of Nephrology : JASN · 2017
    Randomized trial120 participantsCardiovascular Support
  23. Randomized, placebo-controlled, double-blind clinical trial on the contributions of vitamin D in the control of cardiovascular risk factors, depressive symptoms and suicide risk.
    Porto C; Petribu K; Barbosa N; Magalhães R; Lira C; Porto AB; Markman-Filho B; Lordsleem A; Calado E; Magalhães J; Sougey E; Silva T; Junio A; Bandeira F; Leão R · American heart journal plus : cardiology research and practice · 2025
    Randomized trial224 participantsCardiovascular Support
  24. Dose responses of vitamin D3 supplementation on arterial stiffness in overweight African Americans with vitamin D deficiency: A placebo controlled randomized trial.
    Raed A; Bhagatwala J; Zhu H; Pollock NK; Parikh SJ; Huang Y; Havens R; Kotak I; Guo DH; Dong Y · PloS one · 2017
    Randomized trial70 participantsCardiovascular Support
  25. Paricalcitol and endothelial function in chronic kidney disease trial.
    Zoccali C; Curatola G; Panuccio V; Tripepi R; Pizzini P; Versace M; Bolignano D; Cutrupi S; Politi R; Tripepi G; Ghiadoni L; Thadhani R; Mallamaci F · Hypertension (Dallas, Tex. : 1979) · 2015
    Randomized trial88 participantsHeart HealthCardiovascular Support
  26. The impact of vitamin D food fortification and health outcomes in children: a systematic review and meta-regression.
    Al Khalifah R; Alsheikh R; Alnasser Y; Alsheikh R; Alhelali N; Naji A; Al Backer N · Systematic reviews · 2021
    Meta-analysis20 studies pooledCognitive Support
  27. Vitamin D Supplementation Improves Cognitive Function Through Reducing Oxidative Stress Regulated by Telomere Length in Older Adults with Mild Cognitive Impairment: A 12-Month Randomized Controlled Trial.
    Yang T; Wang H; Xiong Y; Chen C; Duan K; Jia J; Ma F · Journal of Alzheimer's disease : JAD · 2021
    Randomized trial183 participantsCognitive Support
  28. Effects of vitamin D supplementation on cognitive function and blood Aβ-related biomarkers in older adults with Alzheimer's disease: a randomised, double-blind, placebo-controlled trial.
    Jia J; Hu J; Huo X; Miao R; Zhang Y; Ma F · Journal of neurology, neurosurgery, and psychiatry · 2020
    Randomized trial210 participantsCognitive Support
  29. Dietary vitamin D intake and 2-year changes in cognitive function in older adults with overweight or obesity and metabolic syndrome.
    Vázquez-Lorente H; Ni J; Paz-Graniel I; Toledo E; Corella D; Castañer O; Martínez JA; Alonso-Gómez ÁM; Wärnberg J; Vioque J; Romaguera D; López-Miranda J; Estruch R; Tinahones FJ; Lapetra J; Serra-Majem L; Bouzalmate-Hajjaj A; Tur JA; Pérez RMM; Fanlo M; Delgado-Rodríguez M; Bustelo AB; Vidal J; Vázquez C; Daimiel L; Ros E; Fernández-Aranda F; Rognoni T; Babio N; Asensio EM; Pérez-Vega KA; Garcia-Rios A; Compañ-Gabucio L; Cueto-Galán R; Zulet MA; Nafria M; Casas R; Cano-Ibáñez N; Tojal-Sierra L; Gómez-Pérez AM; Goñi N; Sorli JV; Zomeño MD; Arenas-Larriva AP; Jiménez-Sellés P; Basterra-Gortari J; Fitó M; Salas-Salvadó J · GeroScience · 2025
    Cohort study5,454 participantsCognitive Support
  30. Gestational vitamin D concentration and child cognitive development: a longitudinal cohort study in the Environmental influences on Child Health Outcomes Program.
    Melough MM; McGrath M; Palmore M; Collett BR; Kerver JM; Hockett CW; Schmidt RJ; Kelly RS; Lyall K; Zhao Q; Hipwell AE; Korrick SA; Gilbert-Diamond D; Weiss ST; Chu SH; Mirzakhani H; Porter JM; Sathyanarayana S; ECHO Cohort Consortium · The American journal of clinical nutrition · 2025
    Cohort study912 participantsCognitive Support
  31. Effect of Vitamin D Supplementation on Human Gut Microbiota: A Systematic Review of Randomized Controlled Trials.
    Zeb F; Osaili T; Hashim M; Alkalbani N; Papandreou D; Cheikh Ismail L; Naja F; Radwan H; Hasan H; Obaid RS; Savvaidis I; AlBlooshi S; Alam I · Nutrition reviews · 2026
    Systematic review1,458 participants14 studies pooledDigestive Health
  32. Vitamin D3 Induced Decrease in IL-17 and Malondialdehyde, and Increase in IL-10 and Total Antioxidant Capacity Levels in Patients with Irritable Bowel Syndrome.
    Amani R; Abbasnezhad A; Hajiani E; Cheraghian B; Abdoli Z; Choghakhori R · Iranian journal of immunology : IJI · 2018
    Randomized trial90 participantsDigestive Health
  33. Effect of vitamin D on gastrointestinal symptoms and health-related quality of life in irritable bowel syndrome patients: a randomized double-blind clinical trial.
    Abbasnezhad A; Amani R; Hajiani E; Alavinejad P; Cheraghian B; Ghadiri A · Neurogastroenterology and motility · 2018
    Randomized trial90 participantsGeneral HealthDigestive Health
  34. Maternal vitamin D intakes during pregnancy and child health outcome.
    Nasantogtokh E; Ganmaa D; Altantuya S; Amgalan B; Enkhmaa D · The Journal of steroid biochemistry and molecular biology · 2023
    Randomized trial311 participantsDigestive Health
  35. Vitamin D metabolites and the gut microbiome in older men.
    Thomas RL; Jiang L; Adams JS; Xu ZZ; Shen J; Janssen S; Ackermann G; Vanderschueren D; Pauwels S; Knight R; Orwoll ES; Kado DM · Nature communications · 2020
    Cross-sectional study567 participantsDigestive Health
  36. Effect of Vitamin D Supplementation on Fatigue in Multiple Sclerosis: A Systematic Review and Meta-Analysis.
    López-Muñoz P; Torres-Costoso AI; Fernández-Rodríguez R; Guzmán-Pavón MJ; de Arenas-Arroyo SN; Basco-López JÁ; Reina-Gutiérrez S · Nutrients · 2023
    Meta-analysis345 participants5 studies pooledEnergy
  37. Vitamin D Supplementation in Adolescents and Young Adults With Juvenile Systemic Lupus Erythematosus for Improvement in Disease Activity and Fatigue Scores: A Randomized, Double-Blind, Placebo-Controlled Trial.
    Lima GL; Paupitz J; Aikawa NE; Takayama L; Bonfa E; Pereira RM · Arthritis care & research · 2016
    Randomized trial40 participantsEnergy
  38. Vitamin D in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome After COVID-19 or Vaccination: A Randomized Controlled Trial.
    Kodama S; Nakata M; Konishi N; Yoshino M; Fujisawa A; Naganuma M; Kobayashi Y; Hirai Y; Kitagawa A; Miyokawa M; Mishima R; Teramukai S; Fukushima M · Nutrients · 2026
    Randomized trial91 participantsEnergy
  39. The effects of vitamin D supplementation on disease activity and fatigue in Libyan rheumatoid arthritis patients.
    Elfituri S · Reumatologia · 2024
    Randomized trial68 participantsEnergy
  40. The effect of home-based aerobic training and vitamin D supplementation on fatigue and quality of life in patients with multiple sclerosis during COVID-19 outbreak.
    Bahmani E; Hoseini R; Amiri E · Science & sports · 2022
    Randomized trial40 participantsEnergy
  41. Effect of Calcifediol on Physical Performance and Muscle Strength Parameters: A Systematic Review and Meta-Analysis.
    Barbagallo M; Veronese N; Di Prazza A; Pollicino F; Carruba L; La Carrubba A; Dominguez LJ · Nutrients · 2022
    Meta-analysis5,446 participants7 studies pooledMuscle GainFitness
  42. Effects of vitamin D supplementation on upper and lower body muscle strength levels in healthy individuals. A systematic review with meta-analysis.
    Tomlinson PB; Joseph C; Angioi M · Journal of science and medicine in sport · 2016
    Meta-analysis310 participants7 studies pooledFitness
  43. Influence of Sunlight and Oral D3 Supplementation on Serum 25(OH)D Concentration and Exercise Performance in Elite Soccer Players.
    Michalczyk MM; Gołaś A; Maszczyk A; Kaczka P; Zając A · Nutrients · 2021
    Randomized trial33 participantsFitness
  44. Effects of Vitamin D Supplementation in Elite Athletes: A Systematic Review.
    Wyatt PB; Reiter CR; Satalich JR; O'Neill CN; Edge C; Cyrus JW; O'Connell RS; Vap AR · Orthopaedic journal of sports medicine · 2024
    Systematic review482 participants14 studies pooledFitness
  45. Association between serum vitamin D levels and cardiorespiratory fitness in the adult population of the USA.
    Marawan A; Kurbanova N; Qayyum R · European journal of preventive cardiology · 2020
    Cross-sectional study1,995 participantsFitness
  46. Vitamin D supplementation for prevention of mortality in adults.
    Bjelakovic G; Gluud LL; Nikolova D; Whitfield K; Wetterslev J; Simonetti RG; Bjelakovic M; Gluud C · The Cochrane database of systematic reviews · 2014
    Meta-analysis95,286 participants159 studies pooledGeneral Health
  47. The impact of vitamin D administration on mortality in COVID-19 patients: a systematic review and meta-analysis of randomized controlled trials.
    Kow CS; Ramachandram DS; Hasan SS; Wong Z; Thiruchelvam K · Inflammopharmacology · 2024
    Meta-analysis2,495 participants19 studies pooledGeneral Health
  48. Vitamin D Status and Mortality: A Systematic Review of Observational Studies.
    Heath AK; Kim IY; Hodge AM; English DR; Muller DC · International journal of environmental research and public health · 2019
    Systematic review84 studies pooledGeneral Health
  49. Meta-analysis of long-term vitamin D supplementation on overall mortality.
    Zheng Y; Zhu J; Zhou M; Cui L; Yao W; Liu Y · PloS one · 2014
    Meta-analysis42 studies pooledGeneral Health
  50. Increased prevalence of vitamin D deficiency in patients with alopecia areata: a systematic review and meta-analysis.
    Lee S; Kim BJ; Lee CH; Lee WS · Journal of the European Academy of Dermatology and Venereology : JEADV · 2018
    Meta-analysis2,039 participants14 studies pooledHair Health
  51. Intralesional vitamin D3 in treatment of alopecia areata: A randomized controlled clinical trial.
    Rashad AF; Elgamal E; Fouda I · Journal of cosmetic dermatology · 2022
    Randomized trial60 participantsHair Health
  52. Vitamin D and its Analogs in Treatment of Mild to Moderate Alopecia Areata: Systematic Review and Meta-Analysis.
    Alsaati AA; Kaliyadan F; Alsaadoun D; Alzakry LM; Alzabadin RA; Hakami TH; Rubaian NFB · Indian dermatology online journal · 2025
    Meta-analysisHair Health
  53. Topical calcipotriol vs narrowband ultraviolet B in treatment of alopecia areata: a randomized-controlled trial.
    El Taieb MA; Hegazy EM; Ibrahim HM; Osman AB; Abualhamd M · Archives of dermatological research · 2020
    Randomized trial60 participantsHair Health
  54. Serum 25 hydroxyvitamin D in non-scarring alopecia: A systematic review and meta-analysis.
    Chen Y; Dong X; Wang Y; Li Y; Xiong L; Li L · Journal of cosmetic dermatology · 2024
    Meta-analysis10,670 participants23 studies pooledHair Health
  55. Vitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysis.
    Martineau AR; Jolliffe DA; Greenberg L; Aloia JF; Bergman P; Dubnov-Raz G; Esposito S; Ganmaa D; Ginde AA; Goodall EC; Grant CC; Janssens W; Jensen ME; Kerley CP; Laaksi I; Manaseki-Holland S; Mauger D; Murdoch DR; Neale R; Rees JR; Simpson S; Stelmach I; Trilok Kumar G; Urashima M; Camargo CA; Griffiths CJ; Hooper RL · Health technology assessment (Winchester, England) · 2020
    Meta-analysis11,321 participants25 studies pooledImmunity
  56. Association Between Vitamin D and Influenza: Meta-Analysis and Systematic Review of Randomized Controlled Trials.
    Zhu Z; Zhu X; Gu L; Zhan Y; Chen L; Li X · Frontiers in nutrition · 2022
    Meta-analysis4,859 participants10 studies pooledImmunity
  57. Vitamin D3 and deconvoluting a rash.
    Ernst MK; Evans ST; Techner JM; Rothbaum RM; Christensen LF; Onay UV; Biyashev D; Demczuk MM; Nguyen CV; Honda KS; McCormick TS; Tsoi LC; Gudjonsson JE; Cooper KD; Lu KQ · JCI insight · 2023
    Randomized trial28 participantsImmunity
  58. Effect of vitamin D3 supplementation on cellular immunity and inflammatory markers in COVID-19 patients admitted to the ICU.
    Bychinin MV; Klypa TV; Mandel IA; Yusubalieva GM; Baklaushev VP; Kolyshkina NA; Troitsky AV · Scientific reports · 2022
    Randomized trial110 participantsImmunity
  59. Current opinion on the role of vitamin D supplementation in respiratory infections and asthma/COPD exacerbations: A need to establish publication guidelines for overcoming the unpublished data.
    Anitua E; Tierno R; Alkhraisat MH · Clinical nutrition (Edinburgh, Scotland) · 2022
    Meta-analysis50,554 participants65 studies pooledImmunity
  60. Three Doses of Vitamin D and Cognitive Outcomes in Older Women: A Double-Blind Randomized Controlled Trial.
    Castle M; Fiedler N; Pop LC; Schneider SJ; Schlussel Y; Sukumar D; Hao L; Shapses SA · The journals of gerontology. Series A, Biological sciences and medical sciences · 2021
    Randomized trialMental Focus
  61. Vitamin D and executive function: a preliminary report.
    Hansen AL; Dahl L; Bakke L; Thayer JF · Perceptual and motor skills · 2012
    Cross-sectional study25 participantsMental Focus
  62. Effects of Vitamin D Supplementation on Cognitive Function in Older Adults: A Grading of Recommendations Assessment, Development, and Evaluation (GRADE) Methodology-Assessed Systematic Review and Meta-Analysis of Randomized Clinical Trials.
    Behrouzi R; Shahinfar H; Jazayeri S · Nutrition reviews · 2026
    Meta-analysis9 studies pooledMental Focus
  63. Maternal vitamin D concentrations are associated with faster childhood reaction time and response speed, but not with motor fluency and flexibility, at the age of 5-6 years: the Amsterdam Born Children and their Development (ABCD) Study.
    Brouwer-Brolsma EM; Vrijkotte TGM; Feskens EJM · The British journal of nutrition · 2019
    Cohort study1,854 participantsMental Focus
  64. Serum 25-hydroxyvitamin D and cognitive decline in the very old: the Newcastle 85+ Study.
    Granic A; Hill TR; Kirkwood TB; Davies K; Collerton J; Martin-Ruiz C; von Zglinicki T; Saxby BK; Wesnes KA; Collerton D; Mathers JC; Jagger C · European journal of neurology · 2015
    Cohort study775 participantsMental Focus
  65. Effects of vitamin D supplementation on insulin resistance and lipid metabolic profiles in women with gestational diabetes mellitus: A randomized controlled trial.
    Duan Y; Zhang S; Ma X; Li L; Jia K · African journal of reproductive health · 2026
    Randomized trial120 participantsMetabolism Boost
  66. Vitamin D3 improves glucose metabolism and attenuates inflammation in prediabetic human and mice.
    Zhang Y; Ni P; Miao Y; Chen H; Tang L; Song H; Li W; Li X · The Journal of nutritional biochemistry · 2024
    Randomized trialMetabolism Boost
  67. Effects of vitamin D and calcium supplementation on pancreatic β cell function, insulin sensitivity, and glycemia in adults at high risk of diabetes: the Calcium and Vitamin D for Diabetes Mellitus (CaDDM) randomized controlled trial.
    Mitri J; Dawson-Hughes B; Hu FB; Pittas AG · The American journal of clinical nutrition · 2011
    Randomized trial92 participantsMetabolism Boost
  68. The Effects of Vitamin D Supplementation on Glycemic Control, Lipid Profiles and C-Reactive Protein Among Patients with Cardiovascular Disease: a Systematic Review and Meta-Analysis of Randomized Controlled Trials.
    Ostadmohammadi V; Milajerdi A; Ghayour-Mobarhan M; Ferns G; Taghizadeh M; Badehnoosh B; Mirzaei H; Asemi Z · Current pharmaceutical design · 2020
    Meta-analysis630 participants8 studies pooledMetabolism Boost
  69. The Effect of Improved Serum 25-Hydroxyvitamin D Status on Glycemic Control in Diabetic Patients: A Meta-Analysis.
    Mirhosseini N; Vatanparast H; Mazidi M; Kimball SM · The Journal of clinical endocrinology and metabolism · 2017
    Meta-analysis1,528 participants24 studies pooledMetabolism Boost
  70. Meta-analysis of the effect of vitamin D on depression.
    Wang L; Su S; Liu Y · Frontiers in psychiatry · 2025
    Meta-analysis20 studies pooledMood Support
  71. A randomized controlled trial of vitamin D supplementation on perinatal depression: in Iranian pregnant mothers.
    Vaziri F; Nasiri S; Tavana Z; Dabbaghmanesh MH; Sharif F; Jafari P · BMC pregnancy and childbirth · 2017
    Randomized trial169 participantsMood Support
  72. Prospective associations between vitamin D and depression in middle-aged adults: findings from the UK Biobank cohort.
    Ronaldson A; Arias de la Torre J; Gaughran F; Bakolis I; Hatch SL; Hotopf M; Dregan A · Psychological medicine · 2022
    Cohort study139,128 participantsMood Support
  73. Association Between Low Vitamin D Levels and Depression: A Systematic Review and Meta-Analysis.
    Karim S; Natche J; Babli SA; Avinash; Matakhov D; Ferdous S; Jeyakkodi H; Alamu OS; Rizwanullah U; Hameed SA · Cureus · 2026
    Meta-analysis49,931 participants15 studies pooledMood Support
  74. Vitamin D Alleviates Anxiety and Depression in Elderly People with Prediabetes: A Randomized Controlled Study.
    Zaromytidou E; Koufakis T; Dimakopoulos G; Drivakou D; Konstantinidou S; Rakitzi P; Grammatiki M; Manthou E; Notopoulos A; Iakovou I; Gotzamani-Psarrakou A; Kotsa K · Metabolites · 2023
    Randomized trial90 participantsMood SupportStress Relief
  75. Active vitamin D treatment in the prevention of sarcopenia in adults with prediabetes (DPVD ancillary study): a randomised controlled trial.
    Kawahara T; Suzuki G; Mizuno S; Tominaga N; Toda M; Toyama N; Inazu T; Kawahara C; Okada Y; Tanaka Y · The lancet. Healthy longevity · 2024
    Randomized trial1,094 participantsMuscle Gain
  76. Effects of Leucine Supplementation in Older Adults with Sarcopenia: A Meta-Analysis.
    Huang C; Hsieh MH · Nutrients · 2025
    Meta-analysis566 participantsMuscle Gain
  77. Influence of vitamin D on sarcopenia pathophysiology: A longitudinal study in humans and basic research in knockout mice.
    Mizuno T; Hosoyama T; Tomida M; Yamamoto Y; Nakamichi Y; Kato S; Kawai-Takaishi M; Ishizuka S; Nishita Y; Tange C; Shimokata H; Imagama S; Otsuka R · Journal of cachexia, sarcopenia and muscle · 2022
    Cohort study1,653 participantsMuscle Gain
  78. A randomized study on the effect of vitamin D₃ supplementation on skeletal muscle morphology and vitamin D receptor concentration in older women.
    Ceglia L; Niramitmahapanya S; da Silva Morais M; Rivas DA; Harris SS; Bischoff-Ferrari H; Fielding RA; Dawson-Hughes B · The Journal of clinical endocrinology and metabolism · 2014
    Randomized trial21 participantsMuscle Gain
  79. Effects of an 8-week high-dose vitamin D supplementation on fatigue and neuropsychiatric manifestations in post-COVID syndrome: A randomized controlled trial.
    Charoenporn V; Tungsukruthai P; Teacharushatakit P; Hanvivattanakul S; Sriyakul K; Sukprasert S; Kamalashiran C; Tungsukruthai S; Charernboon T · Psychiatry and clinical neurosciences · 2024
    Randomized trial80 participantsStress Relief
  80. The Influence of Vitamin D Intake and Status on Mental Health in Children: A Systematic Review.
    Głąbska D; Kołota A; Lachowicz K; Skolmowska D; Stachoń M; Guzek D · Nutrients · 2021
    Systematic review24 studies pooledStress Relief
  81. Vitamin D3 enhances mood in healthy subjects during winter.
    Lansdowne AT; Provost SC · Psychopharmacology · 1998
    Randomized trial44 participantsStress Relief
  82. Comparative Effects of Etelcalcetide and Maxacalcitol on Serum Calcification Propensity in Secondary Hyperparathyroidism: A Randomized Clinical Trial.
    Shoji T; Nakatani S; Kabata D; Mori K; Shintani A; Yoshida H; Takahashi K; Ota K; Fujii H; Ueda S; Nishi S; Nakatani T; Yoshiyama M; Goto K; Hamada T; Imanishi M; Ishimura E; Kagitani S; Kato Y; Kumeda Y; Maekawa K; Matsumura T; Nagayama H; Obi Y; Ohno Y; Sai Y; Sakurai M; Sasaki S; Shidara K; Shoji S; Tsujimoto Y; Yamakawa K; Yasuda H; Yodoi S; Inaba M; Emoto M · Clinical journal of the American Society of Nephrology : CJASN · 2021
    Randomized trial326 participantsStress Relief
  83. Effect of Two Different Doses of Vitamin D Supplementation on Metabolic Profiles of Insulin-Resistant Patients with Polycystic Ovary Syndrome.
    Jamilian M; Foroozanfard F; Rahmani E; Talebi M; Bahmani F; Asemi Z · Nutrients · 2018
    Randomized trial90 participantsTestosterone Support
  84. Androgens and hirsutism score of overweight women with polycystic ovary syndrome improved after vitamin D treatment: A randomized placebo controlled clinical trial.
    Al-Bayyari N; Al-Domi H; Zayed F; Hailat R; Eaton A · Clinical nutrition (Edinburgh, Scotland) · 2021
    Randomized trial60 participantsTestosterone Support
  85. Association between plasma 25-OH vitamin D and testosterone levels in men.
    Nimptsch K; Platz EA; Willett WC; Giovannucci E · Clinical endocrinology · 2012
    Case-control study1,362 participantsTestosterone Support
  86. Causal Link Between Vitamin D and Total Testosterone in Men: A Mendelian Randomization Analysis.
    Chen C; Zhai H; Cheng J; Weng P; Chen Y; Li Q; Wang C; Xia F; Wang N; Lu Y · The Journal of clinical endocrinology and metabolism · 2020
    Other4,254 participantsTestosterone Support
  87. Associations of vitamin D status and vitamin D-related polymorphisms with sex hormones in older men.
    Rafiq R; van Schoor NM; Sohl E; Zillikens MC; Oosterwerff MM; Schaap L; Lips P; de Jongh RT · The Journal of steroid biochemistry and molecular biology · 2017
    Cohort study643 participantsTestosterone Support
  88. Effect of vitamin D supplementation along with weight loss diet on meta-inflammation and fat mass in obese subjects with vitamin D deficiency: A double-blind placebo-controlled randomized clinical trial.
    Lotfi-Dizaji L; Mahboob S; Aliashrafi S; Vaghef-Mehrabany E; Ebrahimi-Mameghani M; Morovati A · Clinical endocrinology · 2020
    Randomized trial44 participantsWeight Loss
  89. Vitamin D Supplementation and Genetic Polymorphisms Impact on Weight Loss Diet Outcomes in Caucasians: A Randomized Double-Blind Placebo-Controlled Clinical Study.
    Xenos K; Papasavva M; Raptis A; Katsarou MS; Drakoulis N · Frontiers in medicine · 2022
    Randomized trial125 participantsWeight Loss
  90. Effect of Vitamin D Supplementation in Early Life on Children's Growth and Body Composition: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.
    Ma K; Wei SQ; Bi WG; Weiler HA; Wen SW · Nutrients · 2021
    Meta-analysis3,960 participants11 studies pooledWeight Loss
  91. Can Vitamin D supplementation enhance the effectiveness of exercise-induced weight loss in overweight or obese adults? Evidence from integrated transcriptomic and meta-analysis.
    Peng T; Zhang Z; Liang W; Zhang J · Frontiers in nutrition · 2025
    Meta-analysis481 participants8 studies pooledWeight Loss
  92. Vitamin D receptor Cdx-2-dependent response of central obesity to vitamin D intake in the subjects with type 2 diabetes: a randomised clinical trial.
    Shab-Bidar S; Neyestani TR; Djazayery A · The British journal of nutrition · 2016
    Randomized trial60 participantsWeight Loss
  93. Vitamin D supplementation for cardiometabolic risk markers in pregnant women based on the gestational diabetes mellitus or obesity status : a randomized clinical trial.
    Yin WJ; Wang P; Ma SS; Tao RX; Hu HL; Jiang XM; Zhang Y; Tao FB; Zhu P · European journal of nutrition · 2024
    Randomized trial1,537 participantsHeart Health
  94. Vitamin D Supplementation, Serum 25(OH)D Concentrations and Cardiovascular Disease Risk Factors: A Systematic Review and Meta-Analysis.
    Mirhosseini N; Rainsbury J; Kimball SM · Frontiers in cardiovascular medicine · 2020
    Meta-analysis81 studies pooledHeart Health
  95. Does vitamin D supplementation modulate metabolic risk factors of cardiovascular disease? A systematic review and meta-analysis of clinical trials.
    Abumweis S; Alqadi S; Al Tarteer A; Alrefai W; Alzoughool F; Jew S; Qudah T · Asia Pacific journal of clinical nutrition · 2026
    Meta-analysis45 studies pooledHeart Health
  96. Knee effusion-synovitis volume measurement and effects of vitamin D supplementation in patients with knee osteoarthritis.
    Wang X; Cicuttini F; Jin X; Wluka AE; Han W; Zhu Z; Blizzard L; Antony B; Winzenberg T; Jones G; Ding C · Osteoarthritis and cartilage · 2018
    Randomized trial413 participantsJoint Health
  97. Vitamin D Deficiency Leads to Poorer Health Outcomes and Greater Length of Stay After Total Knee Arthroplasty and Supplementation Improves Outcomes: A Systematic Review and Meta-Analysis.
    Vivek K; Kamal R; Perera E; Gupte CM · JBJS reviews · 2024
    Meta-analysis146,054 participants10 studies pooledJoint Health
  98. Does vitamin D improve symptomatic and structural outcomes in knee osteoarthritis? A systematic review and meta-analysis.
    Zhao ZX; He Y; Peng LH; Luo X; Liu M; He CS; Chen J · Aging clinical and experimental research · 2021
    Meta-analysis1,599 participants6 studies pooledJoint Health
  99. Baseline 25-hydroxyvitamin D levels predict the effects of vitamin D supplementation on joint symptoms and cartilage loss in patients with knee osteoarthritis.
    Wang T; Zheng S; Jin X; Cen H; Zhu Z; Han W; Wluka A; Cicuttini F; Cao P; Ding C · Rheumatology advances in practice · 2025
    Randomized trial413 participantsJoint Health
  100. The Efficacy and Safety of Disease-Modifying Osteoarthritis Drugs for Knee and Hip Osteoarthritis-a Systematic Review and Network Meta-Analysis.
    Yang W; Sun C; He SQ; Chen JY; Wang Y; Zhuo Q · Journal of general internal medicine · 2021
    Meta-analysis11,890 participants28 studies pooledJoint Health
  101. Associations Between Vitamin D Intake and Progression to Incident Advanced Age-Related Macular Degeneration.
    Merle BMJ; Silver RE; Rosner B; Seddon JM · Investigative ophthalmology & visual science · 2017
    Cohort study2,146 participantsVision Support
  102. Circulating vitamin D concentration and age-related macular degeneration: Systematic review and meta-analysis.
    Annweiler C; Drouet M; Duval GT; Paré PY; Leruez S; Dinomais M; Milea D · Maturitas · 2017
    Meta-analysis11 studies pooledVision Support
  103. Low serum vitamin D is associated with axial length and risk of myopia in young children.
    Tideman JW; Polling JR; Voortman T; Jaddoe VW; Uitterlinden AG; Hofman A; Vingerling JR; Franco OH; Klaver CC · European journal of epidemiology · 2017
    Cohort study2,666 participantsVision Support
  104. The effect of vitamin D supplementation on the outcome of treatment with bevacizumab in diabetic macular edema: a randomized clinical trial.
    Fekri S; Soheilian M; Roozdar S; Abtahi SH; Nouri H · International ophthalmology · 2022
    Randomized trial83 participantsVision Support
  105. Vitamin D Deficiency and Dry Eye Disease: A Retrospective Cohort Study.
    Shmushkevich SB; Bajrami S; Beauchamp B; Kane JS; Mutawe DL; Hollinger JC; Marks VA; Parekh PK; Rothman AL; Ansari ZA; Williams BK; Galor A · American journal of ophthalmology · 2026
    Cohort study12,095,004 participantsVision Support
  106. Recommendations for the definition, evaluation, and treatment of nail psoriasis in adult patients with no or mild skin psoriasis: A dermatologist and nail expert group consensus.
    Rigopoulos D; Baran R; Chiheb S; Daniel CR; Di Chiacchio N; Gregoriou S; Grover C; Haneke E; Iorizzo M; Pasch M; Piraccini BM; Rich P; Richert B; Rompoti N; Rubin AI; Singal A; Starace M; Tosti A; Triantafyllopoulou I; Zaiac M · Journal of the American Academy of Dermatology · 2019
    Guideline / consensusNail Health
  107. Vitamins for the Management of Nail Disease: A Literature Review.
    Curtis KL; Lipner SR · Skin appendage disorders · 2025
    Narrative reviewNail Health
  108. Nail involvement in psoriatic arthritis.
    Sobolewski P; Walecka I; Dopytalska K · Reumatologia · 2019
    Narrative reviewNail Health
  109. Psoriasis treatment in difficult locations: scalp, nails, and intertriginous areas.
    Wozel G · Clinics in dermatology · 2009
    Narrative reviewNail Health
  110. Nail psoriasis: clinical presentation and best practice recommendations.
    Edwards F; de Berker D · Drugs · 2010
    Narrative reviewNail Health
  111. Association of serum 25-hydroxyvitamin D with sleep disorders in individuals with prediabetes and diabetes: a prospective cohort study.
    Liu G; Li H; Ma Y; Shi Y; Han J; Li F; Fang L; Tian S; Cheng Y · Frontiers in endocrinology · 2025
    Cohort study81,533 participantsSleep Support
  112. A meta-analysis: Does vitamin D play a promising role in sleep disorders?
    Yan S; Tian Z; Zhao H; Wang C; Pan Y; Yao N; Guo Y; Wang H; Li B; Cui W · Food science & nutrition · 2024
    Meta-analysisSleep Support
  113. Influence of sunlight on the association between 25-hydroxyvitamin D levels and sleep quality in Brazilian adults: A population-based study.
    de Menezes-Júnior LAA; Sabião TDS; de Moura SS; Batista AP; de Menezes MC; Carraro JCC; Andrade ACS; Machado-Coelho GLL; Meireles AL · Nutrition (Burbank, Los Angeles County, Calif.) · 2023
    Cross-sectional study1,709 participantsSleep Support
  114. Serum 25(OH)D levels and obstructive sleep apnea syndrome severity in patients without comorbidities: a systematic review and meta-analysis.
    Serafin M; Vaninetti M; Mohamed I; Strambi LF; Caprioglio A · Sleep & breathing = Schlaf & Atmung · 2024
    Meta-analysis3,573 participants24 studies pooledSleep Support
  115. Vitamin D Supplementation and Sleep: A Systematic Review and Meta-Analysis of Intervention Studies.
    Abboud M · Nutrients · 2022
    Meta-analysis19 studies pooledSleep Support
  116. Vitamin D accelerates clinical recovery from tuberculosis: results of the SUCCINCT Study [Supplementary Cholecalciferol in recovery from tuberculosis]. A randomized, placebo-controlled, clinical trial of vitamin D supplementation in patients with pulmonary tuberculosis'.
    Salahuddin N; Ali F; Hasan Z; Rao N; Aqeel M; Mahmood F · BMC infectious diseases · 2013
    Randomized trial259 participantsWeight Gain
  117. Correction of neonatal vitamin D status using 1000 IU vitamin D/d increased lean body mass by 12 months of age compared with 400 IU/d: a randomized controlled trial.
    Razaghi M; Gharibeh N; Vanstone CA; Sotunde OF; Khamessan A; Wei SQ; McNally D; Rauch F; Jones G; Kimmins S; Weiler HA · The American journal of clinical nutrition · 2023
    Randomized trialWeight Gain
  118. Effect of treatment of vitamin D deficiency and insufficiency during pregnancy on fetal growth indices and maternal weight gain: a randomized clinical trial.
    Hashemipour S; Ziaee A; Javadi A; Movahed F; Elmizadeh K; Javadi EH; Lalooha F · European journal of obstetrics, gynecology, and reproductive biology · 2014
    Randomized trial130 participantsWeight Gain
  119. Effects of vitamin A and vitamin D3 supplementation on child growth and development in low- and middle-income countries: a systematic review and meta-analysis.
    Peng L; Zhao J; Duan C; Yan J; Li D; Yang Y; He D · Translational pediatrics · 2026
    Meta-analysis6,340 participants12 studies pooledWeight Gain
  120. Prevalence of hypovitaminosis D and associated factors in obese Spanish children.
    Durá-Travé T; Gallinas-Victoriano F; Chueca-Guindulain MJ; Berrade-Zubiri S · Nutrition & diabetes · 2017
    Cross-sectional study546 participantsWeight Gain