Vitamin D

    Written by:
    Morgan Pfiffner, Bill Willis

    Fact-checked

    by:

    Nick Milazzo
    Last Updated: January 21, 2025

    Vitamin D is a fat-soluble vitamin that our skin synthesizes when exposed to the sun. It benefits us in many ways, from bone health to mood.

    Overview

    Dosage information

    IU vs. μg

    Historically, it’s been more common to see vitamin D dosed in international units (IU), rather than micrograms (μg). In 2016, however, the US Food and Drug Administration (FDA) announced that, by 2021, supplement labels had to display vitamin D content in μg.[1] IU is still commonly seen alongside μg, so it’s good to become familiar with both units: 40 IU is equivalent to 1 μg.

    How many grams of vitamin D should I take per day?

    The ideal daily dose of vitamin D should correspond to its recommended daily allowance (RDA), which is currently 400–800 IU (10–20 μg) a day, but this may be too low for many adults. For moderate supplementation, a standard daily dose of 1,000–2,000 IU (25–50 μg) of vitamin D3 is sufficient to meet the needs of most people. Higher daily doses are in the range of 20–80 IU (0.5–2 μg) per kilogram of body weight.

    Vitamin D should be taken daily with meals or a source of fat.[2][3]

    Regarding the daily recommended dose for babies and children, please refer to the question “Should vitamin D supplements be given to infants and children?”.

    What is the ideal daily dose of vitamin D for pregnant women?

    The recommended daily dose of vitamin D for pregnant women varies across different countries. In the US, pregnant women are recommended to take 600 IU (15 μg) of vitamin D daily, unless they have a vitamin D deficiency, which will require higher doses.[4] In the UK, the recommended dosage is slightly lower, 400 IU (10 μg) daily.[5].

    What is the ideal dose of vitamin D for menopausal women?

    The recommended daily dose of vitamin D for women during menopause has not yet been established. However, research has shown that daily doses of 2000–4800 IU (50–120 μg) taken regularly were effective at correcting vitamin D deficiencies and maintaining vitamin D levels.[6]

    What is the maximum dose of vitamin D?

    The Upper Tolerable Intake Level, which is the maximum daily dose of a nutrient that is unlikely to cause side effects, is 4,000 IU (100 μg) per day in the United States and Canada.[4] This is considered a high dose of vitamin D; however, doses above this level are sometimes used for short periods of time (e.g., to reverse a severe vitamin D deficiency quickly), with safety likely determined by the dose and duration of supplementation. High-dose vitamin D supplementation should be done under medical supervision in order to monitor blood levels and watch for signs of vitamin D toxicity (e.g., hypercalcemia).

    What types of vitamin D are there?

    Vitamin D3 supplementation (cholecalciferol) is recommended over D2 supplementation (ergocalciferol), because D3 tends to raise blood levels more effectively.

    Vitamin D is usually available in a wide range of doses and forms (e.g., tablets, capsules, soft gels, drops, powder). Which form to choose and how much to take will depend on the vitamin D content in each supplement and the individual’s specific requirements. For instance, for an adult wanting to take 2000 IU (50 μg) a day of vitamin D, the correct daily dose of a vitamin D drops supplement containing 1000 IU (25 μg) per drop would be 2 drops a day.

    Factors that influence vitamin D levels

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    Frequently asked questions

    Update History

    Examine Database References

    1. Upper Respiratory Tract Infection Symptoms - Martineau AR, MacLaughlin BD, Hooper RL, Barnes NC, Jolliffe DA, Greiller CL, Kilpin K, McLaughlin D, Fletcher G, Mein CA, Hoti M, Walton R, Grigg J, Timms PM, Rajakulasingam RK, Bhowmik A, Rowe M, Venton TR, Choudhury AB, Simcock DE, Sadique Z, Monteiro WR, Corrigan CJ, Hawrylowicz CM, Griffiths CJDouble-blind randomised placebo-controlled trial of bolus-dose vitamin D3 supplementation in adults with asthma (ViDiAs)Thorax.(2015 May)
    2. Upper Respiratory Tract Infection Symptoms - Denlinger LC, King TS, Cardet JC, Craig T, Holguin F, Jackson DJ, Kraft M, Peters SP, Ross K, Sumino K, Boushey HA, Jarjour NN, Wechsler ME, Wenzel SE, Castro M, Avila PC, NHLBI AsthmaNet InvestigatorsVitamin D Supplementation and the Risk of Colds in Patients with AsthmaAm J Respir Crit Care Med.(2016 Mar 15)
    3. Asthma Symptoms - Fedora K, Setyoningrum RA, Aina Q, Rosyidah LN, Ni'mah NL, Titiharja FFVitamin D supplementation decrease asthma exacerbations in children: a systematic review and meta-analysis of randomized controlled trials.Ann Med.(2024 Jul 3)
    4. Endometriosis-associated pelvic pain - James L Nodler, Amy D DiVasta, Allison F Vitonis, Sarah Karevicius, Maggie Malsch, Vishnudas Sarda, Ayotunde Fadayomi, Holly R Harris, Stacey A MissmerSupplementation with vitamin D or ω-3 fatty acids in adolescent girls and young women with endometriosis (SAGE): a double-blind, randomized, placebo-controlled trialAm J Clin Nutr.(2020 Jul 1)
    5. Endometriosis-associated pelvic pain - Fariba Almassinokiani, Sepideh Khodaverdi, Masoud Solaymani-Dodaran, Peyman Akbari, Abdolreza PazoukiEffects of Vitamin D on Endometriosis-Related Pain: A Double-Blind Clinical TrialMed Sci Monit.(2016 Dec 17)
    6. Low-density lipoprotein (LDL) - Abolfazl Mehdizadehkashi, Samaneh Rokhgireh, Kobra Tahermanesh, Neda Eslahi, Sara Minaeian, Mansooreh SamimiThe effect of vitamin D supplementation on clinical symptoms and metabolic profiles in patients with endometriosisGynecol Endocrinol.(2021 Jan 29)
    7. Pelvic Pain - Zhou IW, Zhang AL, Tsang MS, Xue CCVitamin D for primary dysmenorrhea and endometriosis-related pain - A systematic review of registered RCTs.PLoS One.(2025)
    8. Upper Respiratory Tract Infection Risk - 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 RLVitamin D supplementation to prevent acute respiratory infections: individual participant data meta-analysisHealth Technol Assess.(2019 Jan)
    9. Upper Respiratory Tract Infection Risk - Ginde AA, Blatchford P, Breese K, Zarrabi L, Linnebur SA, Wallace JI, Schwartz RSHigh-Dose Monthly Vitamin D for Prevention of Acute Respiratory Infection in Older Long-Term Care Residents: A Randomized Clinical TrialJ Am Geriatr Soc.(2017 Mar)
    10. Upper Respiratory Tract Infection Risk - Camargo CA Jr, Ganmaa D, Frazier AL, Kirchberg FF, Stuart JJ, Kleinman K, Sumberzul N, Rich-Edwards JWRandomized trial of vitamin D supplementation and risk of acute respiratory infection in MongoliaPediatrics.(2012 Sep)
    11. Upper Respiratory Tract Infection Risk - Aloia J, Islam S, Mikhail MVitamin D and Acute Respiratory Infections—The PODA TrialOpen Forum Infect. Dis..()
    12. Upper Respiratory Tract Infection Risk - Grant CC, Kaur S, Waymouth E, Mitchell EA, Scragg R, Ekeroma A, Stewart A, Crane J, Trenholme A, Camargo CA JrReduced primary care respiratory infection visits following pregnancy and infancy vitamin D supplementation: a randomised controlled trialActa Paediatr.(2015 Apr)
    13. Multiple Sclerosis Symptoms - Ghasem Mosayebi, Ali Ghazavi, Keyvan Ghasami, Yahya Jand, Parviz KokhaeiTherapeutic effect of vitamin D3 in multiple sclerosis patientsImmunol Invest.(2011)
    14. Multiple Sclerosis Symptoms - Margitta T Kampman, Linn H Steffensen, Svein I Mellgren, Lone JørgensenEffect of vitamin D3 supplementation on relapses, disease progression, and measures of function in persons with multiple sclerosis: exploratory outcomes from a double-blind randomised controlled trialMult Scler.(2012 Aug)
    15. Multiple Sclerosis Symptoms - Pierrot-Deseilligny C, Rivaud-Péchoux S, Clerson P, de Paz R, Souberbielle JCRelationship between 25-OH-D serum level and relapse rate in multiple sclerosis patients before and after vitamin D supplementationTher Adv Neurol Disord.(2012 Jul)
    16. Multiple Sclerosis Symptoms - J Killestein, E L J Hoogervorst, M Reif, N F Kalkers, A C Van Loenen, P G M Staats, R W Gorter, B M J Uitdehaag, C H PolmanSafety, tolerability, and efficacy of orally administered cannabinoids in MSNeurology.(2002 May 14)
    17. Multiple Sclerosis Symptoms - P Fox, P G Bain, S Glickman, C Carroll, J ZajicekThe effect of cannabis on tremor in patients with multiple sclerosisNeurology.(2004 Apr 13)
    18. Multiple Sclerosis Symptoms - Raymond Hupperts, Joost Smolders, Reinhold Vieth, Trygve Holmøy, Kurt Marhardt, Myriam Schluep, Joep Killestein, Frederik Barkhof, Manolo Beelke, Luigi M E Grimaldi, SOLAR Study GroupRandomized trial of daily high-dose vitamin D 3 in patients with RRMS receiving subcutaneous interferon β-1aNeurology.(2019 Nov 12)
    19. Multiple Sclerosis Symptoms - William Camu, Philippe Lehert, Charles Pierrot-Deseilligny, Patrick Hautecoeur, Anne Besserve, Anne-Sophie Jean Deleglise, Marianne Payet, Eric Thouvenot, Jean Claude SouberbielleCholecalciferol in relapsing-remitting MS: A randomized clinical trial (CHOLINE)Neurol Neuroimmunol Neuroinflamm.(2019 Aug 6)
    20. Multiple Sclerosis Symptoms - Jody Corey-Bloom, Tanya Wolfson, Anthony Gamst, Shelia Jin, Thomas D Marcotte, Heather Bentley, Ben GouauxSmoked cannabis for spasticity in multiple sclerosis: a randomized, placebo-controlled trialCMAJ.(2012 Jul 10)
    21. Multiple Sclerosis Symptoms - Vahid Shaygannejad, Mohsen Janghorbani, Fereshteh Ashtari, Hamed DehghanEffects of adjunct low-dose vitamin d on relapsing-remitting multiple sclerosis progression: preliminary findings of a randomized placebo-controlled trialMult Scler Int.(2012)
    22. Upper Respiratory Tract Infection Symptoms - Dubnov-Raz G, Rinat B, Hemilä H, Choleva L, Cohen AH, Constantini NWVitamin D supplementation and upper respiratory tract infections in adolescent swimmers: a randomized controlled trialPediatr Exerc Sci.(2015 Feb)
    23. Upper Respiratory Tract Infection Symptoms - Murdoch DR, Slow S, Chambers ST, Jennings LC, Stewart AW, Priest PC, Florkowski CM, Livesey JH, Camargo CA, Scragg REffect of vitamin D3 supplementation on upper respiratory tract infections in healthy adults: the VIDARIS randomized controlled trialJAMA.(2012 Oct 3)
    24. Upper Respiratory Tract Infection Symptoms - Goodall EC, Granados AC, Luinstra K, Pullenayegum E, Coleman BL, Loeb M, Smieja MVitamin D3 and gargling for the prevention of upper respiratory tract infections: a randomized controlled trialBMC Infect Dis.(2014 May 19)
    25. Upper Respiratory Tract Infection Symptoms - Shimizu Y, Ito Y, Yui K, Egawa K, Orimo HIntake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison StudyJ Nutr Health Aging.(2018)
    26. Upper Respiratory Tract Infection Symptoms - Jung HC, Seo MW, Lee S, Kim SW, Song JKVitamin D₃ Supplementation Reduces the Symptoms of Upper Respiratory Tract Infection during Winter Training in Vitamin D-Insufficient Taekwondo Athletes: A Randomized Controlled TrialInt J Environ Res Public Health.(2018 Sep 14)
    27. Upper Respiratory Tract Infection Symptoms - Li-Ng M, Aloia JF, Pollack S, Cunha BA, Mikhail M, Yeh J, Berbari NA randomized controlled trial of vitamin D3 supplementation for the prevention of symptomatic upper respiratory tract infectionsEpidemiol Infect.(2009 Oct)
    28. Upper Respiratory Tract Infection Symptoms - Laaksi I, Ruohola JP, Mattila V, Auvinen A, Ylikomi T, Pihlajamäki HVitamin D supplementation for the prevention of acute respiratory tract infection: a randomized, double-blinded trial among young Finnish menJ Infect Dis.(2010 Sep 1)
    29. Upper Respiratory Tract Infection Risk - Aglipay M, Birken CS, Parkin PC, Loeb MB, Thorpe K, Chen Y, Laupacis A, Mamdani M, Macarthur C, Hoch JS, Mazzulli T, Maguire JL, TARGet Kids! CollaborationEffect of High-Dose vs Standard-Dose Wintertime Vitamin D Supplementation on Viral Upper Respiratory Tract Infections in Young Healthy ChildrenJAMA.(2017 Jul 18)
    30. Upper Respiratory Tract Infection Risk - Avenell A, Cook JA, Maclennan GS, Macpherson GCVitamin D supplementation to prevent infections: a sub-study of a randomised placebo-controlled trial in older people (RECORD trial, ISRCTN 51647438)Age Ageing.(2007 Sep)
    31. Upper Respiratory Tract Infection Risk - Rees JR, Hendricks K, Barry EL, Peacock JL, Mott LA, Sandler RS, Bresalier RS, Goodman M, Bostick RM, Baron JAVitamin D3 supplementation and upper respiratory tract infections in a randomized, controlled trialClin Infect Dis.(2013 Nov)
    32. Upper Respiratory Tract Infection Risk - Camargo CA, Sluyter J, Stewart AW, Khaw KT, Lawes CMM, Toop L, Waayer D, Scragg REffect of monthly high-dose vitamin D supplementation on acute respiratory infections in older adults: A randomized controlled trialClin Infect Dis.(2019 Aug 17)
    33. Upper Respiratory Tract Infection Risk - Bergman P, Norlin AC, Hansen S, Rekha RS, Agerberth B, Björkhem-Bergman L, Ekström L, Lindh JD, Andersson JVitamin D3 supplementation in patients with frequent respiratory tract infections: a randomised and double-blind intervention studyBMJ Open.(2012 Dec 13)
    34. Upper Respiratory Tract Infection Risk - Loeb M, Dang AD, Thiem VD, Thanabalan V, Wang B, Nguyen NB, Tran HTM, Luong TM, Singh P, Smieja M, Maguire J, Pullenayegum EEffect of Vitamin D supplementation to reduce respiratory infections in children and adolescents in Vietnam: A randomized controlled trialInfluenza Other Respir Viruses.(2019 Mar)
    35. Upper Respiratory Tract Infection Risk - Simpson S, Mei I, Stewart N, Blizzard L, Tettey P, Taylor BWeekly cholecalciferol supplementation results in significant reductions in infection risk among the vitamin D deficient: results from the CIPRIS pilot RCTBMC Nutr.()
    36. Upper Respiratory Tract Infection Risk - Hauger H, Ritz C, Mortensen C, Mølgaard C, Metzdorff SB, Frøkiær H, Damsgaard CTWinter cholecalciferol supplementation at 55°N has little effect on markers of innate immune defense in healthy children aged 4-8 years: a secondary analysis from a randomized controlled trialEur J Nutr.(2019 Jun)
    37. Low-density lipoprotein (LDL) - Zittermann A, Frisch S, Berthold HK, Götting C, Kuhn J, Kleesiek K, Stehle P, Koertke H, Koerfer RVitamin D supplementation enhances the beneficial effects of weight loss on cardiovascular disease risk markersAm J Clin Nutr.(2009 May)
    38. Interleukin 5 - Barker T, Martins TB, Hill HR, Kjeldsberg CR, Henriksen VT, Dixon BM, Schneider ED, Dern A, Weaver LKDifferent doses of supplemental vitamin D maintain interleukin-5 without altering skeletal muscle strength: a randomized, double-blind, placebo-controlled study in vitamin D sufficient adultsNutr Metab (Lond).(2012 Mar 9)
    39. Tuberculosis Symptoms - Ganmaa D, Giovannucci E, Bloom BR, Fawzi W, Burr W, Batbaatar D, Sumberzul N, Holick MF, Willett WCVitamin D, tuberculin skin test conversion, and latent tuberculosis in Mongolian school-age children: a randomized, double-blind, placebo-controlled feasibility trialAm J Clin Nutr.(2012 Aug)
    40. Upper Respiratory Tract Infection Symptoms - Martineau AR, Hanifa Y, Witt KD, Barnes NC, Hooper RL, Patel M, Stevens N, Enayat Z, Balayah Z, Syed A, Knight A, Jolliffe DA, Greiller CL, McLaughlin D, Venton TR, Rowe M, Timms PM, Clark D, Sadique Z, Eldridge SM, Griffiths CJDouble-blind randomised controlled trial of vitamin D3 supplementation for the prevention of acute respiratory infection in older adults and their carers (ViDiFlu)Thorax.(2015 Oct)
    41. Upper Respiratory Tract Infection Symptoms - Manaseki-Holland S, Qader G, Isaq Masher M, Bruce J, Zulf Mughal M, Chandramohan D, Walraven GEffects of vitamin D supplementation to children diagnosed with pneumonia in Kabul: a randomised controlled trialTrop Med Int Health.(2010 Oct)
    42. Pneumonia Symptoms - Choudhary N, Gupta PVitamin D supplementation for severe pneumonia--a randomized controlled trialIndian Pediatr.(2012 Jun)
    43. Risk Of Cardiovascular Disease - Wang L, Manson JE, Song Y, Sesso HDSystematic review: Vitamin D and calcium supplementation in prevention of cardiovascular eventsAnn Intern Med.(2010 Mar 2)
    44. Pain - McAlindon T, LaValley M, Schneider E, Nuite M, Lee JY, Price LL, Lo G, Dawson-Hughes BEffect of vitamin D supplementation on progression of knee pain and cartilage volume loss in patients with symptomatic osteoarthritis: a randomized controlled trialJAMA.(2013 Jan 9)
    45. Glycemic Control - Carrillo AE, Flynn MG, Pinkston C, Markofski MM, Jiang Y, Donkin SS, Teegarden DImpact of vitamin D supplementation during a resistance training intervention on body composition, muscle function, and glucose tolerance in overweight and obese adultsClin Nutr.(2012 Aug 31)
    46. Glycemic Control - Harris SS, Pittas AG, Palermo NJA randomized, placebo-controlled trial of vitamin D supplementation to improve glycaemia in overweight and obese African AmericansDiabetes Obes Metab.(2012 Sep)
    47. Muscle Mass - Salehpour A, Hosseinpanah F, Shidfar F, Vafa M, Razaghi M, Dehghani S, Hoshiarrad A, Gohari MA 12-week double-blind randomized clinical trial of vitamin D3 supplementation on body fat mass in healthy overweight and obese womenNutr J.(2012 Sep 22)
    48. Blood glucose - Rajakumar K, Moore CG, Khalid AT, Vallejo AN, Virji MA, Holick MF, Greenspan SL, Arslanian S, Reis SEEffect of vitamin D3 supplementation on vascular and metabolic health of vitamin D-deficient overweight and obese children: a randomized clinical trial.Am J Clin Nutr.(2020-Apr-01)
    49. Type 2 Diabetes Incidence - Tobias DK, Pradhan AD, Duran EK, Li C, Song Y, Buring JE, Cook NR, Mora S, Manson JEVitamin D supplementation vs. placebo and incident type 2 diabetes in an ancillary study of the randomized Vitamin D and Omega-3 Trial.Nat Commun.(2025 Apr 8)
    50. Fibromyalgia Symptoms - Florian Wepner, Raphael Scheuer, Birgit Schuetz-Wieser, Peter Machacek, Elisabeth Pieler-Bruha, Heide S Cross, Julia Hahne, Martin FriedrichEffects of vitamin D on patients with fibromyalgia syndrome: a randomized placebo-controlled trialPain.(2014 Feb)
    51. Fibromyalgia Symptoms - J F de Carvalho, F A G da Rocha Araújo, L M A da Mota, R B Aires, R P de AraujoVitamin D Supplementation Seems to Improve Fibromyalgia Symptoms: Preliminary ResultsIsr Med Assoc J.(2018 Jun)
    52. Fibromyalgia Symptoms - Atalay Dogru, Ayse Balkarli, Veli Cobankara, Sevket Ercan Tunc, Mehmet SahinEffects of Vitamin D Therapy on Quality of Life in Patients with FibromyalgiaEurasian J Med.(2017 Jun)
    53. Fever - Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida HRandomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildrenAm J Clin Nutr.(2010 May)
    54. Upper Respiratory Tract Infection Symptoms - Zhou J, Du J, Huang L, Wang Y, Shi Y, Lin HPreventive Effects of Vitamin D on Seasonal Influenza A in Infants: A Multicenter, Randomized, Open, Controlled Clinical TrialPediatr Infect Dis J.(2018 Aug)
    55. Influenza Risk - Jorde R, Witham M, Janssens W, Rolighed L, Borchhardt K, de Boer IH, Grimnes G, Hutchinson MSVitamin D supplementation did not prevent influenza-like illness as diagnosed retrospectively by questionnaires in subjects participating in randomized clinical trialsScand J Infect Dis.(2012 Feb)
    56. Influenza Risk - Urashima M, Mezawa H, Noya M, Camargo CA JrEffects of vitamin D supplements on influenza A illness during the 2009 H1N1 pandemic: a randomized controlled trialFood Funct.(2014 Sep)
    57. Testosterone - Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann AEffect of vitamin D supplementation on testosterone levels in menHorm Metab Res.(2011 Mar)
    58. Risk Of Cardiovascular Disease - Dobnig H, Pilz S, Scharnagl H, Renner W, Seelhorst U, Wellnitz B, Kinkeldei J, Boehm BO, Weihrauch G, Maerz WIndependent association of low serum 25-hydroxyvitamin d and 1,25-dihydroxyvitamin d levels with all-cause and cardiovascular mortalityArch Intern Med.(2008 Jun 23)
    59. COVID-19 Severity - Igor H Murai, Alan L Fernandes, Lucas P Sales, Ana J Pinto, Karla F Goessler, Camila S C Duran, Carla B R Silva, André S Franco, Marina B Macedo, Henrique H H Dalmolin, Janaina Baggio, Guilherme G M Balbi, Bruna Z Reis, Leila Antonangelo, Valeria F Caparbo, Bruno Gualano, Rosa M R PereiraEffect of a Single High Dose of Vitamin D3 on Hospital Length of Stay in Patients With Moderate to Severe COVID-19: A Randomized Clinical TrialJAMA.(2021 Mar 16)
    60. COVID-19 Severity - Shaun Sabico, Mushira A Enani, Eman Sheshah, Naji J Aljohani, Dara A Aldisi, Naif H Alotaibi, Naemah Alshingetti, Suliman Y Alomar, Abdullah M Alnaami, Osama E Amer, Syed D Hussain, Nasser M Al-DaghriEffects of a 2-Week 5000 IU versus 1000 IU Vitamin D3 Supplementation on Recovery of Symptoms in Patients with Mild to Moderate Covid-19: A Randomized Clinical TrialNutrients.(2021 Jun 24)
    61. COVID-19 Severity - Marta Entrenas Castillo, Luis Manuel Entrenas Costa, José Manuel Vaquero Barrios, Juan Francisco Alcalá Díaz, José López Miranda, Roger Bouillon, José Manuel Quesada Gomez"Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: A pilot randomized clinical study"J Steroid Biochem Mol Biol.(2020 Oct)
    62. Need for mechanical ventilation - Yang Y, Sun W, Yang F, Zhang G, Li X, Sun S, Xing YTherapeutic effects of vitamin D supplementation on COVID-19 aggravation: a systematic review and meta-analysis of randomized controlled trials.Front Pharmacol.(2024)
    63. Need for mechanical ventilation - Zhu L, Zhang Y, Li X, Zou X, Bing P, Qi M, He BVitamin D supplementation for managing COVID-19 in patients with vitamin D deficiency: a systematic review and meta-analysis of randomised controlled trials.BMJ Open.(2025 Mar 26)
    64. Length of hospitalization - Ghoreshi ZA, Charostad J, Arefinia N, Nakhaie M, Rezaei Zadeh Rukerd M, Salajegheh FEffect of vitamin D supplementation on clinical outcomes in adult patients with COVID-19: A GRADE-assessed systematic review and meta-analysis of randomized controlled trials.Pharmacol Res Perspect.(2024 Sep 3)
    65. Length of hospitalization - Sartini M, Del Puente F, Carbone A, Schinca E, Ottria G, Dupont C, Piccinini C, Oliva M, Cristina MLThe Effect of Vitamin D Supplementation Post COVID-19 Infection and Related Outcomes: A Systematic Review and Meta-Analysis.Nutrients.(2024 Nov 5)
    66. Breast Cancer Risk - Garland CF, Gorham ED, Mohr SB, Grant WB, Giovannucci EL, Lipkin M, Newmark H, Holick MF, Garland FCVitamin D and prevention of breast cancer: pooled analysisJ Steroid Biochem Mol Biol.(2007 Mar)
    67. Breast Cancer Risk - Crew KD, Gammon MD, Steck SE, Hershman DL, Cremers S, Dworakowski E, Shane E, Terry MB, Desai M, Teitelbaum SL, Neugut AI, Santella RMAssociation between plasma 25-hydroxyvitamin D and breast cancer riskCancer Prev Res (Phila).(2009 Jun)
    68. Aromatase-Inhibitor Related Joint Pain - Qamar J Khan, Pavan S Reddy, Bruce F Kimler, Priyanka Sharma, Susan E Baxa, Anne P O'Dea, Jennifer R Klemp, Carol J FabianEffect of vitamin D supplementation on serum 25-hydroxy vitamin D levels, joint pain, and fatigue in women starting adjuvant letrozole treatment for breast cancerBreast Cancer Res Treat.(2010 Jan)
    69. Low-density lipoprotein (LDL) - Seibert E, Lehmann U, Riedel A, Ulrich C, Hirche F, Brandsch C, Dierkes J, Girndt M, Stangl GIVitamin D3 supplementation does not modify cardiovascular risk profile of adults with inadequate vitamin D statusEur J Nutr.(2015 Nov 30)
    70. Inflammation - Gepner AD, Ramamurthy R, Krueger DC, Korcarz CE, Binkley N, Stein JHA prospective randomized controlled trial of the effects of vitamin D supplementation on cardiovascular disease riskPLoS One.(2012)
    71. Blood Pressure - Scragg R, Sowers M, Bell CSerum 25-hydroxyvitamin D, ethnicity, and blood pressure in the Third National Health and Nutrition Examination SurveyAm J Hypertens.(2007 Jul)
    72. Sleep Duration - Majid MS, Ahmad HS, Bizhan H, Hosein HZM, Mohammad AThe effect of vitamin D supplement on the score and quality of sleep in 20-50 year-old people with sleep disorders compared with control groupNutr Neurosci.(2018 Sep)
    73. Fibromyalgia Symptoms - David S Arvold, Marilyn J Odean, Maude P Dornfeld, Ronald R Regal, Judith G Arvold, Gene C Karwoski, David J Mast, Paul B Sanford, Robert J SjobergCorrelation of symptoms with vitamin D deficiency and symptom response to cholecalciferol treatment: a randomized controlled trialEndocr Pract.(2009 Apr)
    74. Depression Symptoms - Fu J, Zhang Y, Chen X, Yu X, Yan M, Jing B, Yu H, Li W, Guo QEfficacy of vitamin D supplementation on depressive symptoms in older patients: a meta-analysis of randomized controlled trials.Front Med (Lausanne).(2024 Oct 10)
    75. Parathyroid Hormone - David D Chandy, Jahnavi Kare, Shakal N Singh, Anjoo Agarwal, Vinita Das, Urmila Singh, V Ramesh, Vijayalakshmi BhatiaEffect of vitamin D supplementation, directly or via breast milk for term infants, on serum 25 hydroxyvitamin D and related biochemistry, and propensity to infection: a randomised placebo-controlled trialBr J Nutr.(2016 Jul)
    76. Calcium Absorption - Abrams SA, Hawthorne KM, Chen ZSupplementation with 1000 IU vitamin D/d leads to parathyroid hormone suppression, but not increased fractional calcium absorption, in 4-8-y-old children: a double-blind randomized controlled trialAm J Clin Nutr.(2013 Jan)
    77. Fracture Risk - Bischoff-Ferrari HA, Willett WC, Wong JB, Stuck AE, Staehelin HB, Orav EJ, Thoma A, Kiel DP, Henschkowski JPrevention of nonvertebral fractures with oral vitamin D and dose dependency: a meta-analysis of randomized controlled trialsArch Intern Med.(2009 Mar 23)
    78. Bone turnover markers - Wu M, Bhimavarapu A, Alvarez JA, Hunt WR, Tangpricha VChanges in bone turnover after high-dose vitamin D supplementation during acute pulmonary exacerbation in cystic fibrosis.Bone.(2023-Sep)
    79. Total Antioxidant Capacity (TAC) - Heidari H, Amani R, Feizi A, Askari G, Kohan S, Tavasoli PVitamin D Supplementation for Premenstrual Syndrome-Related inflammation and antioxidant markers in students with vitamin D deficient: a randomized clinical trialSci Rep.(2019 Oct 17)
    80. Depression Symptoms - Dadkhah H, Ebrahimi E, Fathizadeh NEvaluating the effects of vitamin D and vitamin E supplement on premenstrual syndrome: A randomized, double-blind, controlled trialIran J Nurs Midwifery Res.(2016 Mar-Apr)
    81. Anxiety Symptoms - Abdollahi R, Abiri B, Sarbakhsh P, Kashanian M, Vafa MThe Effect of Vitamin D Supplement Consumption on Premenstrual Syndrome in Vitamin D-Deficient Young Girls: A Randomized, Double-Blind, Placebo-Controlled Clinical TrialComplement Med Res.(2019)
    82. Anxiety Symptoms - Tartagni M, Cicinelli MV, Tartagni MV, Alrasheed H, Matteo M, Baldini D, De Salvia M, Loverro G, Montagnani MVitamin D Supplementation for Premenstrual Syndrome-Related Mood Disorders in Adolescents with Severe Hypovitaminosis DJ Pediatr Adolesc Gynecol.(2016 Aug)
    83. Cramps - Bahrami A, Avan A, Sadeghnia HR, Esmaeili H, Tayefi M, Ghasemi F, Nejati Salehkhani F, Arabpour-Dahoue M, Rastgar-Moghadam A, Ferns GA, Bahrami-Taghanaki H, Ghayour-Mobarhan MHigh dose vitamin D supplementation can improve menstrual problems, dysmenorrhea, and premenstrual syndrome in adolescentsGynecol Endocrinol.(2018 Aug)
    84. Glycemic Control - A M Borissova, T Tankova, G Kirilov, L Dakovska, R KovachevaThe effect of vitamin D3 on insulin secretion and peripheral insulin sensitivity in type 2 diabetic patientsInt J Clin Pract.(2003 May)
    85. Insulin - Chen W, Liu L, Hu FEfficacy of vitamin D supplementation on glycaemic control in type 2 diabetes: An updated systematic review and meta-analysis of randomized controlled trials.Diabetes Obes Metab.(2024 Oct 2)
    86. Insulin - Mitri J, Dawson-Hughes B, Hu FB, Pittas AGEffects 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 trialAm J Clin Nutr.(2011 Aug)
    87. Depression Symptoms - Putranto R, Setiati S, Nasrun MW, Witjaksono F, Immanuel S, Subekti I, Harimurti K, Siswanto A, Shatri H, Suwarto S, Megantara MAEffects of cholecalciferol supplementation on depressive symptoms, C-peptide, serotonin, and neurotrophin-3 in type 2 diabetes mellitus: A double-blind, randomized, placebo-controlled trial.Narra J.(2024 Dec)
    88. Glycemic Control - Shaban Nazarian, John V St Peter, Raymond C Boston, Sidney A Jones, Cary N MariashVitamin D3 supplementation improves insulin sensitivity in subjects with impaired fasting glucoseTransl Res.(2011 Nov)
    89. Insulin Resistance - Wallace HJ, Holmes L, Ennis CN, Cardwell CR, Woodside JV, Young IS, Bell PM, Hunter SJ, McKinley MCEffect of vitamin D3 supplementation on insulin resistance and β-cell function in prediabetes: a double-blind, randomized, placebo-controlled trial.Am J Clin Nutr.(2019-Nov-01)
    90. Aromatase-Inhibitor Related Joint Pain - Prieto-Alhambra D, Javaid MK, Servitja S, Arden NK, Martinez-García M, Diez-Perez A, Albanell J, Tusquets I, Nogues XVitamin D threshold to prevent aromatase inhibitor-induced arthralgia: a prospective cohort studyBreast Cancer Res Treat.(2011 Feb)
    91. Insulin - Sepehrmanesh Z, Kolahdooz F, Abedi F, Mazroii N, Assarian A, Asemi Z, Esmaillzadeh AVitamin D Supplementation Affects the Beck Depression Inventory, Insulin Resistance, and Biomarkers of Oxidative Stress in Patients with Major Depressive Disorder: A Randomized, Controlled Clinical TrialJ Nutr.(2016 Feb)
    92. Upper Respiratory Tract Infection Symptoms - Somnath SH, Biswal N, Chandrasekaran V, Jagadisan B, Bobby ZTherapeutic effect of vitamin D in acute lower respiratory infection: A randomized controlled trialClin Nutr ESPEN.(2017 Aug)
    93. All-Cause Mortality - Bjelakovic G, Gluud LL, Nikolova D, Whitfield K, Wetterslev J, Simonetti RG, Bjelakovic M, Gluud CVitamin D supplementation for prevention of mortality in adultsCochrane Database Syst Rev.(2011 Jul 6)
    94. Type 1 Diabetes Incidence - Mohr SB, Garland CF, Gorham ED, Garland FCThe association between ultraviolet B irradiance, vitamin D status and incidence rates of type 1 diabetes in 51 regions worldwideDiabetologia.(2008 Aug)
    95. HbA1c - Kositsawat J, Freeman VL, Gerber BS, Geraci SAssociation of A1C levels with vitamin D status in U.S. adults: data from the National Health and Nutrition Examination SurveyDiabetes Care.(2010 Jun)
    96. Tuberculosis risk - Middelkoop K, Stewart J, Walker N, Delport C, Jolliffe DA, Coussens AK, Nuttall J, Tang JCY, Fraser WD, Griffiths CJ, Kumar GT, Filteau S, Hooper RL, Wilkinson RJ, Bekker LG, Martineau ARVitamin D supplementation to prevent tuberculosis infection in South African schoolchildren: multicenter phase 3 double-blind randomized placebo-controlled trial (ViDiKids).Int J Infect Dis.(2023-Sep)
    97. Power Output - Owens DJ, Sharples AP, Polydorou I, Alwan N, Donovan T, Tang J, Fraser WD, Cooper RG, Morton JP, Stewart C, Close GLA systems-based investigation into vitamin D and skeletal muscle repair, regeneration, and hypertrophyAm J Physiol Endocrinol Metab.(2015 Dec 15)
    98. Pancreatic Cancer Risk - Skinner HG, Michaud DS, Giovannucci E, Willett WC, Colditz GA, Fuchs CSVitamin D intake and the risk for pancreatic cancer in two cohort studiesCancer Epidemiol Biomarkers Prev.(2006 Sep)
    99. Fall Risk - Bischoff-Ferrari HA, Dawson-Hughes B, Staehelin HB, Orav JE, Stuck AE, Theiler R, Wong JB, Egli A, Kiel DP, Henschkowski JFall prevention with supplemental and active forms of vitamin D: a meta-analysis of randomised controlled trialsBMJ.(2009 Oct 1)
    100. Fall Risk - Broe KE, Chen TC, Weinberg J, Bischoff-Ferrari HA, Holick MF, Kiel DPA higher dose of vitamin d reduces the risk of falls in nursing home residents: a randomized, multiple-dose studyJ Am Geriatr Soc.(2007 Feb)
    101. Fall Risk - Michos ED, Kalyani RR, Blackford AL, Sternberg AL, Mitchell CM, Juraschek SP, Schrack JA, Wanigatunga AA, Roth DL, Christenson RH, Miller ER, Appel LJThe Relationship of Falls With Achieved 25-Hydroxyvitamin D Levels From Vitamin D Supplementation: The STURDY Trial.J Endocr Soc.(2022-Jun-01)
    102. Functionality in Elderly or Injured - Guralnik JM, Sternberg AL, Mitchell CM, Blackford AL, Schrack J, Wanigatunga AA, Michos E, Juraschek SP, Szanton S, Kalyani R, Cai Y, Appel LJ,Effects of Vitamin D on Physical Function: Results From the STURDY Trial.J Gerontol A Biol Sci Med Sci.(2022-Aug-12)
    103. Alzheimer's Disease Symptoms - Jingya Jia, Jing Hu, Xiaoxu Huo, Rujuan Miao, Yanping Zhang, Fei MaEffects 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 trialJ Neurol Neurosurg Psychiatry.(2019 Dec)
    104. Blood Pressure - Witham MD, Nadir MA, Struthers ADEffect of vitamin D on blood pressure: a systematic review and meta-analysisJ Hypertens.(2009 Oct)
    105. Bone Mineral Density - Yang Y, Yang M, Su X, Xie FEfficacy of combination therapy of vitamin D and bisphosphonates in the treatment of postmenopausal osteoporosis: a systematic review and meta-analysis.Front Pharmacol.(2024 Nov 21)
    106. Otitis Media Risk - Marchisio P, Consonni D, Baggi E, Zampiero A, Bianchini S, Terranova L, Tirelli S, Esposito S, Principi NVitamin D supplementation reduces the risk of acute otitis media in otitis-prone childrenPediatr Infect Dis J.(2013 Oct)
    107. Cathelicidin - Sanders EC, Burkes RM, Mock JR, Brown TT, Wise RA, Hansel NN, Liu MC, Drummond MBBronchoalveolar Lavage and Plasma Cathelicidin Response to 25-Hydroxy Vitamin D Supplementation: A Pilot Study.Chronic Obstr Pulm Dis.(2021-Jul-28)
    108. Wound Healing - Halschou-Jensen PM, Sauer J, Bouchelouche P, Fabrin J, Brorson S, Ohrt-Nissen SImproved Healing of Diabetic Foot Ulcers After High-dose Vitamin D: A Randomized Double-blinded Clinical Trial.Int J Low Extrem Wounds.(2023-Sep)
    109. Acne Symptoms - Ruikchuchit T, Juntongjin PRole of vitamin D supplement adjunct to topical benzoyl peroxide in acne: a randomized double-blinded controlled study.Int J Womens Dermatol.(2024 Oct)
    110. Bone Mineral Density - Grove-Laugesen D, Ebbehoj E, Watt T, Hansen KW, Rejnmark LChanges in bone density and microarchitecture following treatment of Graves' disease and the effects of vitamin D supplementation. A randomized clinical trial.Osteoporos Int.(2024 Sep 12)
    111. Itching - Li CP, Huang SC, Hsiao Y, Tsai RYEvaluating the Role of Vitamin D in Alleviating Chronic Pruritus: A Meta-Analysis.Int J Mol Sci.(2024 Sep 16)
    112. Inflammation - Masbough F, Kouchek M, Koosha M, Salarian S, Miri M, Raoufi M, Taherpour N, Amniati S, Sistanizad MInvestigating the Effect of High-Dose Vitamin D3 Administration on Inflammatory Biomarkers in Patients with Moderate to Severe Traumatic Brain Injury: A Randomized Clinical Trial.Iran J Med Sci.(2024 Oct)
    113. Irritable Bowel Syndrome Symptoms - .(2024-09-04)
    114. Irritable Bowel Syndrome Symptoms - Qi S, Zhao M, Sun Y, Boro S, Arora B, Rastogi SImpact of vitamin D supplementation on symptom severity and quality of life in patients with irritable bowel syndrome: A meta-analysis.Adv Clin Exp Med.(2025 Jan 24)
    115. Upper Respiratory Tract Infection Risk - Bournot AR, Darling AL, Givens ID, Lovegrove JA, Lanham-New SA, Hart KHEffect of vitamin D status and vitamin D supplementation on immune function and prevention of acute respiratory tract infections in dark-skinned individuals: a systematic review and meta-analysis.Public Health Nutr.(2024 Oct 28)
    116. Depression Symptoms - Ghaemi S, Zeraattalab-Motlagh S, Jayedi A, Shab-Bidar SThe effect of vitamin D supplementation on depression: a systematic review and dose-response meta-analysis of randomized controlled trials.Psychol Med.(2024 Nov 18)
    117. Pre-Eclampsia Risk - Moghib K, Ghanm TI, Abunamoos A, Rajabi M, Moawad SM, Mohsen A, Kasem S, Elsayed K, Sayed M, Dawoud AI, Salomon I, Elmaghreby A, Ismail M, Amer AEfficacy of vitamin D supplementation on the incidence of preeclampsia: a systematic review and meta-analysis.BMC Pregnancy Childbirth.(2024 Dec 23)
    118. Blood glucose - Yu M, Chen S, Liu X, Dong H, Wang DCThe impact of vitamin D supplementation on glycemic control and lipid metabolism in polycystic ovary syndrome: a systematic review of randomized controlled trials.BMC Endocr Disord.(2025 Apr 21)
    119. Risk of Hypocalcemia - Canali L, Pace GM, Russell MD, Gaino F, Malvezzi L, Mazziotti G, Lania A, Spriano G, Mannstadt M, Randolph GW, Mercante GPreoperative Vitamin D Supplementation to Reduce Hypocalcemia Following Total Thyroidectomy: Systematic Review and Meta-Analysis of Randomized Clinical Trials.Head Neck.(2025 Apr 23)