Last update
4/15/2026
Reviewed By
Overview
SCIENTIFIC SCORE
Questionable
Based on 11 Researches
6.5
USERS' SCORE
Good
Based on 2 Reviews
8.5
Supplement Facts
Serving Size: 2 Tablets
Amount Per Serving
%DV
Vitamin D3 (as Cholecalciferol)
13 mcg (500 IU)
63%
Calcium (as Calcium Citrate)
630 mg
48%
Top Medical Research Studies
8
We explored the connection between vitamin D levels and coronary thrombus load in patients who experienced ST-elevation myocardial infarction (STEMI). The study included 77 patients where we measured serum vitamin D levels, thrombus degree, and other relevant factors.
Our findings revealed that a concerning 79.22% of participants showed vitamin D deficiency, with those having milder thrombus loads possessing significantly higher vitamin D levels compared to those with severe thrombus loads. Moreover, as we assessed the severity of coronary artery condition, we noted that patients with higher thrombus burden also had markedly greater scores of atherosclerosis.
Importantly, we found clear negative correlations between vitamin D levels and measures of thrombus burden. Lower vitamin D levels aligned with higher TIMI frame counts—meaning more extensive vascular obstruction—suggesting that vitamin D might play a role in blood clot formation.
Overall, we determined that low 25(OH)D3 levels could be an independent predictor of high coronary artery thrombus load in STEMI patients. These findings highlight the potential significance of monitoring and perhaps addressing vitamin D levels in this vulnerable group.
Our findings revealed that a concerning 79.22% of participants showed vitamin D deficiency, with those having milder thrombus loads possessing significantly higher vitamin D levels compared to those with severe thrombus loads. Moreover, as we assessed the severity of coronary artery condition, we noted that patients with higher thrombus burden also had markedly greater scores of atherosclerosis.
Importantly, we found clear negative correlations between vitamin D levels and measures of thrombus burden. Lower vitamin D levels aligned with higher TIMI frame counts—meaning more extensive vascular obstruction—suggesting that vitamin D might play a role in blood clot formation.
Overall, we determined that low 25(OH)D3 levels could be an independent predictor of high coronary artery thrombus load in STEMI patients. These findings highlight the potential significance of monitoring and perhaps addressing vitamin D levels in this vulnerable group.
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8
We explored the impact of different calcium infusions on clotting risks in neonates undergoing cardiac surgery. Our study involved analyzing data from 135 babies who received either calcium chloride or calcium gluconate during their treatment.
The findings highlighted a significant concern: when using calcium chloride, the incidence of thrombotic events was notably higher compared to those treated with calcium gluconate. Specifically, the odds of experiencing a blood clot were over three times greater in patients given calcium chloride.
With an overall thrombus occurrence of 9.9%, we observed that only 4.6% of the group receiving calcium gluconate developed such complications compared to 15% in the calcium chloride group. The evidence suggests that switching from calcium chloride to calcium gluconate could potentially reduce the risk of harmful blood clots in these vulnerable patients.
The findings highlighted a significant concern: when using calcium chloride, the incidence of thrombotic events was notably higher compared to those treated with calcium gluconate. Specifically, the odds of experiencing a blood clot were over three times greater in patients given calcium chloride.
With an overall thrombus occurrence of 9.9%, we observed that only 4.6% of the group receiving calcium gluconate developed such complications compared to 15% in the calcium chloride group. The evidence suggests that switching from calcium chloride to calcium gluconate could potentially reduce the risk of harmful blood clots in these vulnerable patients.
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4
We investigated the effects of high-dose vitamin D3 on blood clotting parameters in patients suffering from venous thromboembolism (VTE), specifically looking at levels of P-selectin and high-sensitive C-reactive protein (hs-CRP). The study involved 60 participants who were diagnosed with acute deep vein thrombosis or pulmonary embolism.
These patients were randomly divided into two groups—one receiving a single dose of 300,000 IU of vitamin D3 and the other group serving as a control. Over the course of four weeks, we measured the levels of vitamin D, P-selectin, and hs-CRP to assess any changes resulting from the treatment.
While we noticed a significant decline in both P-selectin and hs-CRP in those who received vitamin D3, the overall reductions were not substantial enough to indicate a major benefit. In comparison, only hs-CRP decreased significantly in the control group. Therefore, we conclude that, based on our findings, high-dose vitamin D3 does not show a strong impact on lowering P-selectin levels or hs-CRP in patients with VTE.
These patients were randomly divided into two groups—one receiving a single dose of 300,000 IU of vitamin D3 and the other group serving as a control. Over the course of four weeks, we measured the levels of vitamin D, P-selectin, and hs-CRP to assess any changes resulting from the treatment.
While we noticed a significant decline in both P-selectin and hs-CRP in those who received vitamin D3, the overall reductions were not substantial enough to indicate a major benefit. In comparison, only hs-CRP decreased significantly in the control group. Therefore, we conclude that, based on our findings, high-dose vitamin D3 does not show a strong impact on lowering P-selectin levels or hs-CRP in patients with VTE.
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Most Useful Reviews
9
Maintained blood clotting
1 people found this helpful
My husband has been on this calcium for nearly two years after his thyroid surgery. It is essential for him due to his affected parathyroid glands. With this supplement, his calcium levels remain nearly normal, unlike with other pharmacy options. The price for such quality is excellent, especially in bulk.
Read More
7.5
Balanced blood clotting
1 people found this helpful
I began taking this after my doctor identified a deficiency in vitamin D and calcium through blood tests. After several months of use, a retest showed that my calcium levels had normalised.
Read More
Medical Researches
SCIENTIFIC SCORE
Questionable
Based on 11 Researches
6.5
- All Researches
9
We explored the effects of vitamin D3 on blood clot formation in mice lacking the klotho protein, which plays a role in regulating vitamin D3 levels. In our analysis, we focused on how klotho deficiency impacts platelet function and calcium signaling, pivotal mechanisms involved in clotting.
Our findings revealed that klotho-deficient platelets exhibited significantly reduced responses to activation, indicating that they might not form clots effectively. Specifically, we observed that calcium signaling pathways, essential for platelet activation and aggregation, were notably inhibited in these mice. The investigation utilized multiple methods, including measuring calcium levels and evaluating platelet function through various biochemical and cellular techniques.
Interestingly, when klotho-deficient mice were given a low-vitamin D diet, we discovered that their platelet function improved, suggesting a direct link between vitamin D3 levels and platelet activity. The reduced activity was associated with decreased expression of critical signaling proteins involved in calcium entry, which vitamin D3 helps regulate. Overall, our study presents evidence that vitamin D3 deficiency due to klotho absence may hinder proper blood clotting mechanisms.
Our findings revealed that klotho-deficient platelets exhibited significantly reduced responses to activation, indicating that they might not form clots effectively. Specifically, we observed that calcium signaling pathways, essential for platelet activation and aggregation, were notably inhibited in these mice. The investigation utilized multiple methods, including measuring calcium levels and evaluating platelet function through various biochemical and cellular techniques.
Interestingly, when klotho-deficient mice were given a low-vitamin D diet, we discovered that their platelet function improved, suggesting a direct link between vitamin D3 levels and platelet activity. The reduced activity was associated with decreased expression of critical signaling proteins involved in calcium entry, which vitamin D3 helps regulate. Overall, our study presents evidence that vitamin D3 deficiency due to klotho absence may hinder proper blood clotting mechanisms.
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9
We evaluated the potential of vitamin D3, specifically calcitriol, in combination with other medications to prevent deep vein thrombosis (VTE) in renal transplant recipients (RTR). Focusing on how these treatments might influence the occurrence of blood clots, we followed a group of 769 RTRs over several months post-transplant.
Our findings revealed that 96 of these recipients experienced a first episode of VTE. We noticed a significant difference in rates of blood clots among those who received calcitriol alongside angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs). In fact, recipients on the combination therapy had a markedly lower rate of VTE, showing a promising 60% reduction in risk.
However, it is important to note that the isolated effect of vitamin D3 without other treatments wasn't fully determined in this study. While calcitriol showed favorable outcomes when used with blood pressure medications, further research could help clarify its individual impact on clot prevention. Overall, this research highlights the importance of collaborative strategies in managing thrombotic complications for transplant patients.
Our findings revealed that 96 of these recipients experienced a first episode of VTE. We noticed a significant difference in rates of blood clots among those who received calcitriol alongside angiotensin-converting enzyme inhibitors (ACEi) and angiotensin receptor blockers (ARBs). In fact, recipients on the combination therapy had a markedly lower rate of VTE, showing a promising 60% reduction in risk.
However, it is important to note that the isolated effect of vitamin D3 without other treatments wasn't fully determined in this study. While calcitriol showed favorable outcomes when used with blood pressure medications, further research could help clarify its individual impact on clot prevention. Overall, this research highlights the importance of collaborative strategies in managing thrombotic complications for transplant patients.
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9
We explored the role of calcium in promoting blood coagulation using a new zeolite-embedded regenerated cellulose aerogel (Z-RCA). This innovative hemostatic agent was designed to minimize common issues seen with previous zeolite-based products, like heat-induced tissue damage and unwanted blood clotting elsewhere in the body.
Our results showed that this aerogel effectively absorbed blood while releasing calcium ions, which play a crucial role in the blood clotting process. By combining the properties of zeolite and the calcium-releasing ability of the aerogel, we found that Z-RCA not only facilitated quicker blood clotting but did so safely, with less risk of adverse effects.
In animal trials, we observed that Z-RCA stopped bleeding faster than existing options like Quikclot and notably reduced blood loss by over 62%. This combination of effectiveness and safety makes Z-RCA a promising solution for achieving efficient hemostasis during emergencies.
Our results showed that this aerogel effectively absorbed blood while releasing calcium ions, which play a crucial role in the blood clotting process. By combining the properties of zeolite and the calcium-releasing ability of the aerogel, we found that Z-RCA not only facilitated quicker blood clotting but did so safely, with less risk of adverse effects.
In animal trials, we observed that Z-RCA stopped bleeding faster than existing options like Quikclot and notably reduced blood loss by over 62%. This combination of effectiveness and safety makes Z-RCA a promising solution for achieving efficient hemostasis during emergencies.
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8
We focused on how 1,25-Dihydroxyvitamin D3, or vitamin D3, affects platelet aggregation, particularly in response to the SARS-CoV-2 spike protein. Individuals with COVID-19 often experience heightened blood clotting, which can lead to serious complications. Our study aimed to uncover the mechanisms behind vitamin D3’s potential benefits in reducing this risk.
Through our experiments, we discovered that vitamin D3 helped reduce platelet aggregation triggered by the spike protein. We noticed that it inhibited certain signaling pathways inside platelets, thereby curbing their ability to clump together. Even when the spike protein was introduced, vitamin D3 managed to lessen the platelet response significantly.
Interestingly, our findings suggest that vitamin D3 works by modulating a specific integrin signaling pathway, known as integrin αIIbβ3 outside-in signaling. We observed that this process involved key proteins that play a role in platelet function. Combining vitamin D3 with a Src family kinase inhibitor showed no added benefits, indicating that vitamin D3's effects might be closely tied to these signaling pathways.
Overall, our study indicates that vitamin D3 has a beneficial role in mitigating the heightened platelet activity associated with the spike protein, offering insights into its potential use as a treatment option during COVID-19.
Through our experiments, we discovered that vitamin D3 helped reduce platelet aggregation triggered by the spike protein. We noticed that it inhibited certain signaling pathways inside platelets, thereby curbing their ability to clump together. Even when the spike protein was introduced, vitamin D3 managed to lessen the platelet response significantly.
Interestingly, our findings suggest that vitamin D3 works by modulating a specific integrin signaling pathway, known as integrin αIIbβ3 outside-in signaling. We observed that this process involved key proteins that play a role in platelet function. Combining vitamin D3 with a Src family kinase inhibitor showed no added benefits, indicating that vitamin D3's effects might be closely tied to these signaling pathways.
Overall, our study indicates that vitamin D3 has a beneficial role in mitigating the heightened platelet activity associated with the spike protein, offering insights into its potential use as a treatment option during COVID-19.
Read More
8
We explored the connection between vitamin D levels and coronary thrombus load in patients who experienced ST-elevation myocardial infarction (STEMI). The study included 77 patients where we measured serum vitamin D levels, thrombus degree, and other relevant factors.
Our findings revealed that a concerning 79.22% of participants showed vitamin D deficiency, with those having milder thrombus loads possessing significantly higher vitamin D levels compared to those with severe thrombus loads. Moreover, as we assessed the severity of coronary artery condition, we noted that patients with higher thrombus burden also had markedly greater scores of atherosclerosis.
Importantly, we found clear negative correlations between vitamin D levels and measures of thrombus burden. Lower vitamin D levels aligned with higher TIMI frame counts—meaning more extensive vascular obstruction—suggesting that vitamin D might play a role in blood clot formation.
Overall, we determined that low 25(OH)D3 levels could be an independent predictor of high coronary artery thrombus load in STEMI patients. These findings highlight the potential significance of monitoring and perhaps addressing vitamin D levels in this vulnerable group.
Our findings revealed that a concerning 79.22% of participants showed vitamin D deficiency, with those having milder thrombus loads possessing significantly higher vitamin D levels compared to those with severe thrombus loads. Moreover, as we assessed the severity of coronary artery condition, we noted that patients with higher thrombus burden also had markedly greater scores of atherosclerosis.
Importantly, we found clear negative correlations between vitamin D levels and measures of thrombus burden. Lower vitamin D levels aligned with higher TIMI frame counts—meaning more extensive vascular obstruction—suggesting that vitamin D might play a role in blood clot formation.
Overall, we determined that low 25(OH)D3 levels could be an independent predictor of high coronary artery thrombus load in STEMI patients. These findings highlight the potential significance of monitoring and perhaps addressing vitamin D levels in this vulnerable group.
Read More
User Reviews
USERS' SCORE
Good
Based on 2 Reviews
8.5
- All Reviews
- Positive Reviews
- Negative Reviews
9
Maintained blood clotting
1 people found this helpful
My husband has been on this calcium for nearly two years after his thyroid surgery. It is essential for him due to his affected parathyroid glands. With this supplement, his calcium levels remain nearly normal, unlike with other pharmacy options. The price for such quality is excellent, especially in bulk.
Read More
7.5
Balanced blood clotting
1 people found this helpful
I began taking this after my doctor identified a deficiency in vitamin D and calcium through blood tests. After several months of use, a retest showed that my calcium levels had normalised.
Read More
Frequently Asked Questions
7.5
Balanced blood clotting
1 people found this helpful
I began taking this after my doctor identified a deficiency in vitamin D and calcium through blood tests. After several months of use, a retest showed that my calcium levels had normalised.
9
Maintained blood clotting
1 people found this helpful
My husband has been on this calcium for nearly two years after his thyroid surgery. It is essential for him due to his affected parathyroid glands. With this supplement, his calcium levels remain nearly normal, unlike with other pharmacy options. The price for such quality is excellent, especially in bulk.
8
We focused on how 1,25-Dihydroxyvitamin D3, or vitamin D3, affects platelet aggregation, particularly in response to the SARS-CoV-2 spike protein. Individuals with COVID-19 often experience heightened blood clotting, which can lead to serious complications. Our study aimed to uncover the mechanisms behind vitamin D3’s potential benefits in reducing this risk.
Through our experiments, we discovered that vitamin D3 helped reduce platelet aggregation triggered by the spike protein. We noticed that it inhibited certain signaling pathways inside platelets, thereby curbing their ability to clump together. Even when the spike protein was introduced, vitamin D3 managed to lessen the platelet response significantly.
Interestingly, our findings suggest that vitamin D3 works by modulating a specific integrin signaling pathway, known as integrin αIIbβ3 outside-in signaling. We observed that this process involved key proteins that play a role in platelet function. Combining vitamin D3 with a Src family kinase inhibitor showed no added benefits, indicating that vitamin D3's effects might be closely tied to these signaling pathways.
Overall, our study indicates that vitamin D3 has a beneficial role in mitigating the heightened platelet activity associated with the spike protein, offering insights into its potential use as a treatment option during COVID-19.
Through our experiments, we discovered that vitamin D3 helped reduce platelet aggregation triggered by the spike protein. We noticed that it inhibited certain signaling pathways inside platelets, thereby curbing their ability to clump together. Even when the spike protein was introduced, vitamin D3 managed to lessen the platelet response significantly.
Interestingly, our findings suggest that vitamin D3 works by modulating a specific integrin signaling pathway, known as integrin αIIbβ3 outside-in signaling. We observed that this process involved key proteins that play a role in platelet function. Combining vitamin D3 with a Src family kinase inhibitor showed no added benefits, indicating that vitamin D3's effects might be closely tied to these signaling pathways.
Overall, our study indicates that vitamin D3 has a beneficial role in mitigating the heightened platelet activity associated with the spike protein, offering insights into its potential use as a treatment option during COVID-19.
2
Vitamin D treatment shows no benefit
In our exploration of how vitamin D might affect blood clotting, we conducted a pilot randomized clinical trial involving 40 patients diagnosed with either deep vein thrombosis or pulmonary embolism. These individuals were vitamin D deficient, which is already known to contribute to the development of blood clots.
We divided the patients into two groups: one received a high dose of vitamin D—50,000 IU weekly for eight weeks followed by less frequent doses—while the control group did not receive any vitamin D. After one and three months, we measured levels of two key biomarkers related to blood clotting: P-selectin and hs-CRP.
We discovered that there was no significant decrease in either biomarker in both groups over the study period. This suggests that treating vitamin D deficiency doesn’t meaningfully impact these specific markers of thrombosis in patients with clotting issues.
However, we did find something interesting. Those who received vitamin D treatment appeared to manage their anticoagulant therapy with warfarin more effectively, using lower doses of the medication. While our initial hypothesis about vitamin D’s direct effect on blood clot markers didn’t hold, this potential interaction with warfarin is intriguing and warrants further investigation in larger studies to better understand the relationship between vitamin D and blood clotting.
We divided the patients into two groups: one received a high dose of vitamin D—50,000 IU weekly for eight weeks followed by less frequent doses—while the control group did not receive any vitamin D. After one and three months, we measured levels of two key biomarkers related to blood clotting: P-selectin and hs-CRP.
We discovered that there was no significant decrease in either biomarker in both groups over the study period. This suggests that treating vitamin D deficiency doesn’t meaningfully impact these specific markers of thrombosis in patients with clotting issues.
However, we did find something interesting. Those who received vitamin D treatment appeared to manage their anticoagulant therapy with warfarin more effectively, using lower doses of the medication. While our initial hypothesis about vitamin D’s direct effect on blood clot markers didn’t hold, this potential interaction with warfarin is intriguing and warrants further investigation in larger studies to better understand the relationship between vitamin D and blood clotting.
4
Calcium and vitamin D3 impact on VTE
We aimed to understand how vitamin D3, when combined with calcium, might affect the risk of developing blood clots, also known as venous thromboembolism (VTE). In a notable study involving over 36,000 postmenopausal women aged between 50 to 79, participants were randomly assigned to receive either daily supplements of 1,000 mg of calcium and 400 IU of vitamin D3 or a placebo. This rigorous double-blind, placebo-controlled design lasted an average of seven years, ensuring that neither the participants nor the researchers knew who was receiving the active treatment.
Our analysis looked closely at the rates of VTE between those taking the supplements and those on the placebo. We found that there was no significant difference in the overall incidence of VTE between the two groups—320 events in the supplement group versus 348 in the placebo group. This translates to a hazard ratio of 0.92, suggesting that the combined supplementation did not lower the risk of blood clots for these generally healthy women.
Interestingly, while the overall risk didn’t change, we observed a noticeable reduction in the risk of idiopathic VTE (where there’s no clear cause) among women who took calcium and vitamin D3, with 40 events compared to 65 in the placebo group. This finding may call for deeper investigation, as it hints at a potential benefit that could be worth exploring further.
To sum up, regular supplementation with calcium and vitamin D3 does not seem to reduce the overall risk of blood clots in postmenopausal women. However, our observation of a lower risk for idiopathic blood clots in the treatment group offers a glimmer of hope for future studies on this topic.
Our analysis looked closely at the rates of VTE between those taking the supplements and those on the placebo. We found that there was no significant difference in the overall incidence of VTE between the two groups—320 events in the supplement group versus 348 in the placebo group. This translates to a hazard ratio of 0.92, suggesting that the combined supplementation did not lower the risk of blood clots for these generally healthy women.
Interestingly, while the overall risk didn’t change, we observed a noticeable reduction in the risk of idiopathic VTE (where there’s no clear cause) among women who took calcium and vitamin D3, with 40 events compared to 65 in the placebo group. This finding may call for deeper investigation, as it hints at a potential benefit that could be worth exploring further.
To sum up, regular supplementation with calcium and vitamin D3 does not seem to reduce the overall risk of blood clots in postmenopausal women. However, our observation of a lower risk for idiopathic blood clots in the treatment group offers a glimmer of hope for future studies on this topic.
References
- Wang R, Tian Z, Wang C, Zhang B, Zhu M, et al. 1,25-Dihydroxyvitamin D3 attenuates platelet aggregation potentiated by SARS-CoV-2 spike protein via inhibiting integrin αIIbβ3 outside-in signaling. Cell Biochem Funct. 2024;42:e4039. 10.1002/cbf.4039
- Uguz B, Oztas S, Zengin I, Topal D, Tiryakioglu SK, et al. Relationship between vitamin D deficiency and thrombus load in patients with ST-elevation myocardial infarction. Eur Rev Med Pharmacol Sci. 2022;26:7015. 10.26355/eurrev_202210_29885
- Hejazi ME, Modarresi-Ghazani F, Hamishehkar H, Mesgari-Abbasi M, Dousti S, et al. The Effect of Treatment of Vitamin D Deficiency on the Level of P-Selectin and hs-CRP in Patients With Thromboembolism: A Pilot Randomized Clinical Trial. J Clin Pharmacol. 2017;57:40. 10.1002/jcph.774
- Blondon M, Rodabough RJ, Budrys N, Johnson KC, Berger JS, et al. The effect of calcium plus vitamin D supplementation on the risk of venous thromboembolism. From the Women's Health Initiative Randomized Controlled Trial. Thromb Haemost. 2015;113:999. 10.1160/TH14-05-0478
- Gholami K, Talasaz AH, Entezari-Maleki T, Salarifar M, Hadjibabaie M, et al. The Effect of High-Dose Vitamin D3 on Soluble P-Selectin and hs-CRP Level in Patients With Venous Thromboembolism: A Randomized Clinical Trial. Clin Appl Thromb Hemost. 2016;22:483. 10.1177/1076029614568715
- Borst O, Münzer P, Schmid E, Schmidt EM, Russo A, et al. 1,25(OH)2 vitamin D3-dependent inhibition of platelet Ca2+ signaling and thrombus formation in klotho-deficient mice. FASEB J. 2014;28:2108. 10.1096/fj.13-239277
- Moscarelli L, Zanazzi M, Bertoni E, Caroti L, Rosso G, et al. Renin angiotensin system blockade and activated vitamin D as a means of preventing deep vein thrombosis in renal transplant recipients. Clin Nephrol. 2011;75:440. PubMed
- Jorde R, Sneve M, Torjesen P, Figenschau Y, Hansen JB. Parameters of the thrombogram are associated with serum 25-hydroxyvitamin D levels at baseline, but not affected during supplementation with vitamin D. Thromb Res. 2010;125:e210. 10.1016/j.thromres.2009.12.011
- Wu-Wong JR. Are vitamin D receptor activators useful for the treatment of thrombosis?. Curr Opin Investig Drugs. 2009;10:919. PubMed
- Jin Z, Chen L, Liu X, Xia R, Li W, et al. Zeolite firmly anchored regenerated cellulose aerogel for efficient and biosafe hemostasis. Int J Biol Macromol. 2025;304:140743. 10.1016/j.ijbiomac.2025.140743
- Tran VA, Griffin EM, Elliott JD, Scholl RL, Hill RB, et al. Thrombotic Complications Associated With Right Atrial Lines in Neonates and Infants Undergoing Cardiac Surgery. Is Calcium Chloride a Culprit?. J Cardiothorac Vasc Anesth. 2025. 10.1053/j.jvca.2025.01.008
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