Clinical trials
Vitamin D clinical trials
Below are recruiting vitamin d clinical trials, each written for real people, not researchers. We’re tracking 119 recruiting studies, each written for real people, not researchers, below.
Recruiting studies
- NCT07681115Recruiting
Vitamin D and pregnancy after frozen embryo transfer
This study looks at how vitamin D levels affect pregnancy success after a frozen embryo transfer. If you are a woman planning this procedure at Fakih IVF, you may be able to join to help researchers understand the link between vitamin D and pregnancy outcomes.
Abu DhabiAges 18–40 - NCT04650880Recruiting
Vitamin D study for irregular periods from PCOS
This trial studies whether taking vitamin D can improve ovulation (the release of an egg) in people with PCOS who have long, irregular menstrual cycles. It may help some participants have more regular ovulation and cycle timing, but you would be monitored with vaginal ultrasound and blood tests.
Hong KongAges 18–40 - NCT07448974RecruitingPhase 3
Vitamin D for Preventing Type 2 Diabetes
This study tests if taking extra vitamin D can help people with prediabetes keep their blood sugar in a healthy range and lower the chance of developing type 2 diabetes. Participants will take high-dose or standard vitamin D and be monitored for about 2 years.
Boston, MassachusettsAges 30–74 - NCT07866391Enrolling by invitation
Vitamin D levels in Zhejiang province
This study looks at vitamin D levels in people in Zhejiang province, China. It aims to understand what factors affect vitamin D levels.
Hangzhou, ZhejiangAges Any age - NCT06919718Recruiting
Vitamin D supplements for new mothers in Idaho
This trial tests whether taking vitamin D supplements can improve mental health and change the nutrients in breast milk for mothers living in Idaho.
Coeur d'Alene, IdahoAges 18–64 - NCT06791044Recruiting
Vitamin D and bone health in neurological patients
This trial looks at how vitamin D levels relate to bone strength and daily function in people with neurological disorders. If you have a neurological condition or are healthy, you may join to help understand how vitamin D affects bone health.
Nea Liosia, AthensAges 20–85 - NCT07400757Recruiting
Statin and vitamin D for active thyroid eye disease
This trial tests whether a statin (a cholesterol-lowering medicine) combined with vitamin D can improve active thyroid eye disease. It may help if you have both eye inflammation and high cholesterol.
Taipei, TaiwanAges 20 years+ - NCT07115342Recruiting
Probiotics and vitamin D for hay fever relief
This study tests whether taking a combination of probiotics (good bacteria) and vitamin D can help reduce hay fever symptoms. It may be a good option if your vitamin D is low and you haven't used probiotics recently.
Tanta, Gharbia GovernorateAges 18–65 - NCT06736002Recruiting
Vitamin D for epilepsy: fewer seizures, less fatigue
This trial tests whether high doses of vitamin D can help reduce seizures and improve fatigue and quality of life in adults with refractory epilepsy who have not responded well to at least two medications.
TainanAges Any age - NCT07241585Recruiting
Vitamin D and light therapy for skin cancer
This trial tests whether taking vitamin D before a special light therapy (photodynamic therapy) can help your body fight nonmelanoma skin cancers like basal or squamous cell cancer. You may join if you are scheduled for surgery to remove a skin tumor.
Cleveland, OhioAges 18 years+ - NCT06061848RecruitingPhase 2/Phase 3
Grass pollen allergy shot with vitamin D
This study tests if adding vitamin D to a new type of allergy shot (ILIT) works better than standard allergy drops for grass pollen allergy. It may help if you have moderate to severe seasonal allergy symptoms.
LundAges 18–60 - NCT07293910RecruitingPhase 2
Comparing stomach acid drugs for clearing H. pylori infection
This trial tests different combinations of stomach acid-reducing drugs, vitamin D or probiotics, to see which works best for clearing an H. pylori infection. H. pylori is a common stomach bacteria that can cause ulcers or stomach discomfort.
Shibīn al KawmAges 18–80 - NCT05838716RecruitingPhase 3
Vitamin D During Hormone Therapy for Prostate Cancer
This trial studies whether taking vitamin D while you are on prostate hormone therapy (ADT) affects your health outcomes. It may help by keeping vitamin D levels in a safe range during treatment.
Newark, DelawareAges 50 years+ - NCT07085598Recruiting
Vitamin D3 for heart nerve health in men with epilepsy
This study tests whether taking vitamin D3 supplements can improve how well the nerves controlling your heart work in men with epilepsy who have low vitamin D levels. If you have low vitamin D from taking certain epilepsy medicines, this trial may help understand if vitamin D can support your heart health.
Dhaka, ShahbagAges 20–40 - NCT07859280Recruiting
Vitamin D in eggs for healthy adults
This study tests whether eating eggs enriched with vitamin D can help raise vitamin D levels in healthy adults. If it works, it could be a simple way to improve vitamin D without supplements.
Ithaca, New YorkAges 18–40 - NCT06745817Enrolling by invitation
Nutrition study for women of childbearing age
This study looks at how well women in their reproductive years get enough nutrients from their diet. It will compare the nutrition of women who eat a regular diet, a vegetarian diet, or a vegan diet.
LjubljanaAges 20–49 - NCT05937789Recruiting
Vitamin D3 during early ICU care to help critically ill adults
This trial tests whether starting vitamin D3 soon after ICU admission helps critically ill adults with low vitamin D levels. It may help correct low vitamin D and possibly improve recovery, depending on your health situation.
TaipeiAges 18 years+ - NCT07199829Recruiting
Vitamin D and K for military healthcare workers
This study tests whether taking vitamin D3 and K2 supplements can improve health in military healthcare workers who have low vitamin D levels. If you qualify, you will stop any current vitamin D or K supplements and take the study supplement for 4.5 months.
Tacoma, WashingtonAges 18–69 - NCT07084597Recruiting
Vitamin D3 for Heart Health in Parkinson's Men
This study tests whether taking vitamin D3 supplements can improve the nerve function that controls your heartbeat in men with Parkinson's disease who have low vitamin D levels. If you have mild to moderate Parkinson's and are on levodopa, this trial may help understand if vitamin D can support your heart health.
Dhaka, ShahbagAges 51–70 - NCT07096414Recruiting
Vitamin D3 and brain waves in men with epilepsy and low vitamin D
This trial tests whether taking vitamin D3 supplements changes brain wave activity in men with epilepsy who also have low vitamin D levels. It aims to see if vitamin D could help improve brain function.
Dhaka, Shahbag, DhakaAges 20–40 - NCT06551337RecruitingPhase 4
Vitamin D for bronchiectasis patients
This trial tests if taking vitamin D can help people with bronchiectasis have fewer flare-ups. It is only for patients who were in an earlier study that checked their vitamin D levels.
Hong KongAges 18 years+ - NCT07012161RecruitingEarly Phase 1
Vitamin D for fibroid symptoms in women with low vitamin D
This trial tests whether taking vitamin D3 can help reduce symptoms like heavy bleeding or pressure from uterine fibroids. It is for women who have fibroids and are also low in vitamin D.
Dhaka, SahabagAges 18–50 - NCT04036188RecruitingEarly Phase 1
Vitamin D and triamcinolone for plaque psoriasis
This early study tests whether taking vitamin D together with triamcinolone (a steroid used on skin) works better for plaque psoriasis than a standard approach. It aims to see if the combination helps clear psoriasis plaques and is safe.
Fairborn, OhioAges 18 years+ - NCT07096336Recruiting
Vitamin D3 and brain waves in Parkinson's study
This study tests whether taking vitamin D3 can improve brain wave patterns in men with Parkinson's disease who have low vitamin D levels. It may help understand if vitamin D supports brain health.
Dhaka, ShahbagAges 51–70
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Common questions
- Are there clinical trials for vitamin d?
- Yes. Clin2 currently lists 119 recruiting vitamin d studies from the U.S. registry, each rewritten for real people, not researchers, so you can see what it’s testing and who it’s for.
- How do I know if I qualify for a vitamin d trial?
- Each study lists its eligibility criteria — rules about age, diagnosis, and prior treatments. On every Clin2 trial page we explain these in words written for real people and offer a short, optional pre-screen for a fit read. The study team makes the final decision.
- Does it cost anything to join a vitamin d trial?
- Using Clin2 is always free. Many trials cover the cost of the study treatment and related visits; some reimburse travel. The study team explains exactly what’s covered before you decide.
Related conditions
Clin2 helps you find and understand clinical trials and does not provide medical advice. Study data comes from ClinicalTrials.gov. Talk with your doctor about whether a specific trial is right for you.