5/24/2025
Last update
5/24/2025
Reviewed By
Reviewed By
Overview
SCIENTIFIC SCORE
Possibly Effective
Based on 11 Researches
7.5
USERS' SCORE
Good
Based on 3 Reviews
8.4
Supplement Facts
Serving Size: 1 Veg Capsule
Amount Per Serving
%DV
Vitamin C (as Ascorbic Acid)
320 mg
356%
Calcium (from Calcium Carbonate)
36 mg
3%
Grape Seed Extract (Vitis vinifera) (min. 90% Total Polyphenols)
100 mg
†
Top Medical Research Studies
9
Vitamin C improves sleep apnea endothelial function
We evaluated how vitamin C might improve endothelial function in patients with obstructive sleep apnea (OSA). In our study, we compared 10 individuals with untreated OSA to 10 matched control subjects without sleep issues. We measured how well blood vessels reacted to increased blood flow, known as flow-mediated dilation (FMD), using ultrasound before and after administering vitamin C.
Our findings revealed a significant difference: baseline FMD was lower in OSA patients compared to the control group. However, after an intravenous injection of vitamin C, the FMD in OSA patients improved dramatically, reaching levels similar to those seen in the healthy controls. Interestingly, vasoreactivity in the control subjects remained unchanged.
These results suggest that oxidative stress might be a key factor contributing to the endothelial dysfunction experienced by individuals with OSA. The positive response to vitamin C opens up exciting possibilities for exploring antioxidant treatments in managing cardiovascular issues related to OSA.
Our findings revealed a significant difference: baseline FMD was lower in OSA patients compared to the control group. However, after an intravenous injection of vitamin C, the FMD in OSA patients improved dramatically, reaching levels similar to those seen in the healthy controls. Interestingly, vasoreactivity in the control subjects remained unchanged.
These results suggest that oxidative stress might be a key factor contributing to the endothelial dysfunction experienced by individuals with OSA. The positive response to vitamin C opens up exciting possibilities for exploring antioxidant treatments in managing cardiovascular issues related to OSA.
Read More
9
We explored how vitamin C treatment affects individuals suffering from sleep apnea, particularly through the lens of intermittent hypoxia. In a study where male Sprague-Dawley rats were subjected to 5% oxygen levels, we observed that intermittent hypoxia led to notable changes in the body. These alterations included heightened carotid body responses to low oxygen, shifts in heart rate variability, and an increase in blood pressure.
The research specifically focused on the effects of ascorbic acid, or vitamin C, at a concentration of 1.25 g/L added to the drinking water of these rats over 21 days. What we found was quite promising: vitamin C treatment significantly reduced markers of oxidative stress in the plasma and carotid body. This antioxidant appeared to counteract the negative effects typically seen during intermittent hypoxia, including improved ventilatory responses to low oxygen levels and stabilization of heart rate and blood pressure.
Overall, our findings suggest that oxidative stress plays a crucial role in the heightened sensitivity and respiratory changes associated with sleep apnea. By mitigating these oxidative effects through vitamin C, we could potentially improve the quality of life for those affected by this condition.
The research specifically focused on the effects of ascorbic acid, or vitamin C, at a concentration of 1.25 g/L added to the drinking water of these rats over 21 days. What we found was quite promising: vitamin C treatment significantly reduced markers of oxidative stress in the plasma and carotid body. This antioxidant appeared to counteract the negative effects typically seen during intermittent hypoxia, including improved ventilatory responses to low oxygen levels and stabilization of heart rate and blood pressure.
Overall, our findings suggest that oxidative stress plays a crucial role in the heightened sensitivity and respiratory changes associated with sleep apnea. By mitigating these oxidative effects through vitamin C, we could potentially improve the quality of life for those affected by this condition.
Read More
8
We delved into an interesting question: can dietary vitamin C help alleviate sleep apnea? To explore this, we examined data from over 68,000 participants in the UK Biobank and focused on their dietary habits, particularly how much vitamin C they consumed. By using a detailed questionnaire to assess their intake and applying advanced statistical methods, we aimed to uncover any potential connections between vitamin C and sleep disorders, especially sleep apnea.
The results were quite revealing. Participants who consumed higher levels of vitamin C, particularly those in the top intake bracket (around 132.88 to 191.51 mg per day), showed a significant reduction in the risk of developing sleep disorders, including sleep apnea. Specifically, we found that this group had a 25% lower risk of sleep apnea compared to those with lower vitamin C intake.
What's even more encouraging is that this protective effect seemed particularly strong among men and those under 60 years old, suggesting that a sufficient intake of vitamin C could be a worthwhile strategy for preventing sleep apnea. Our findings highlight the importance of diet in managing sleep health and point to vitamin C as a valuable nutrient for those struggling with sleep issues.
The results were quite revealing. Participants who consumed higher levels of vitamin C, particularly those in the top intake bracket (around 132.88 to 191.51 mg per day), showed a significant reduction in the risk of developing sleep disorders, including sleep apnea. Specifically, we found that this group had a 25% lower risk of sleep apnea compared to those with lower vitamin C intake.
What's even more encouraging is that this protective effect seemed particularly strong among men and those under 60 years old, suggesting that a sufficient intake of vitamin C could be a worthwhile strategy for preventing sleep apnea. Our findings highlight the importance of diet in managing sleep health and point to vitamin C as a valuable nutrient for those struggling with sleep issues.
Read More
Most Useful Reviews
9
No more snoring
2 people found this helpful
My husband can snore, but since taking this grape seed supplement, there has been no snoring, allowing me to sleep well.
Read More
7.5
Enhanced alertness
4 people found this helpful
I've been taking this supplement for nearly a year. After starting it, I became more alert and energetic, my complexion improved, and my sleep has also enhanced.
Read More
7.5
Improved sleep quality
I recommend this product as I appreciate the quality and brand. The size is average and the packaging is good and airtight. My sleep has improved significantly, and there is no noticeable taste.
Read More
Medical Researches
SCIENTIFIC SCORE
Possibly Effective
Based on 11 Researches
7.5
- All Researches
9
We explored how vitamin C treatment affects individuals suffering from sleep apnea, particularly through the lens of intermittent hypoxia. In a study where male Sprague-Dawley rats were subjected to 5% oxygen levels, we observed that intermittent hypoxia led to notable changes in the body. These alterations included heightened carotid body responses to low oxygen, shifts in heart rate variability, and an increase in blood pressure.
The research specifically focused on the effects of ascorbic acid, or vitamin C, at a concentration of 1.25 g/L added to the drinking water of these rats over 21 days. What we found was quite promising: vitamin C treatment significantly reduced markers of oxidative stress in the plasma and carotid body. This antioxidant appeared to counteract the negative effects typically seen during intermittent hypoxia, including improved ventilatory responses to low oxygen levels and stabilization of heart rate and blood pressure.
Overall, our findings suggest that oxidative stress plays a crucial role in the heightened sensitivity and respiratory changes associated with sleep apnea. By mitigating these oxidative effects through vitamin C, we could potentially improve the quality of life for those affected by this condition.
The research specifically focused on the effects of ascorbic acid, or vitamin C, at a concentration of 1.25 g/L added to the drinking water of these rats over 21 days. What we found was quite promising: vitamin C treatment significantly reduced markers of oxidative stress in the plasma and carotid body. This antioxidant appeared to counteract the negative effects typically seen during intermittent hypoxia, including improved ventilatory responses to low oxygen levels and stabilization of heart rate and blood pressure.
Overall, our findings suggest that oxidative stress plays a crucial role in the heightened sensitivity and respiratory changes associated with sleep apnea. By mitigating these oxidative effects through vitamin C, we could potentially improve the quality of life for those affected by this condition.
Read More
9
Vitamin C improves sleep apnea endothelial function
We evaluated how vitamin C might improve endothelial function in patients with obstructive sleep apnea (OSA). In our study, we compared 10 individuals with untreated OSA to 10 matched control subjects without sleep issues. We measured how well blood vessels reacted to increased blood flow, known as flow-mediated dilation (FMD), using ultrasound before and after administering vitamin C.
Our findings revealed a significant difference: baseline FMD was lower in OSA patients compared to the control group. However, after an intravenous injection of vitamin C, the FMD in OSA patients improved dramatically, reaching levels similar to those seen in the healthy controls. Interestingly, vasoreactivity in the control subjects remained unchanged.
These results suggest that oxidative stress might be a key factor contributing to the endothelial dysfunction experienced by individuals with OSA. The positive response to vitamin C opens up exciting possibilities for exploring antioxidant treatments in managing cardiovascular issues related to OSA.
Our findings revealed a significant difference: baseline FMD was lower in OSA patients compared to the control group. However, after an intravenous injection of vitamin C, the FMD in OSA patients improved dramatically, reaching levels similar to those seen in the healthy controls. Interestingly, vasoreactivity in the control subjects remained unchanged.
These results suggest that oxidative stress might be a key factor contributing to the endothelial dysfunction experienced by individuals with OSA. The positive response to vitamin C opens up exciting possibilities for exploring antioxidant treatments in managing cardiovascular issues related to OSA.
Read More
8
We delved into an interesting question: can dietary vitamin C help alleviate sleep apnea? To explore this, we examined data from over 68,000 participants in the UK Biobank and focused on their dietary habits, particularly how much vitamin C they consumed. By using a detailed questionnaire to assess their intake and applying advanced statistical methods, we aimed to uncover any potential connections between vitamin C and sleep disorders, especially sleep apnea.
The results were quite revealing. Participants who consumed higher levels of vitamin C, particularly those in the top intake bracket (around 132.88 to 191.51 mg per day), showed a significant reduction in the risk of developing sleep disorders, including sleep apnea. Specifically, we found that this group had a 25% lower risk of sleep apnea compared to those with lower vitamin C intake.
What's even more encouraging is that this protective effect seemed particularly strong among men and those under 60 years old, suggesting that a sufficient intake of vitamin C could be a worthwhile strategy for preventing sleep apnea. Our findings highlight the importance of diet in managing sleep health and point to vitamin C as a valuable nutrient for those struggling with sleep issues.
The results were quite revealing. Participants who consumed higher levels of vitamin C, particularly those in the top intake bracket (around 132.88 to 191.51 mg per day), showed a significant reduction in the risk of developing sleep disorders, including sleep apnea. Specifically, we found that this group had a 25% lower risk of sleep apnea compared to those with lower vitamin C intake.
What's even more encouraging is that this protective effect seemed particularly strong among men and those under 60 years old, suggesting that a sufficient intake of vitamin C could be a worthwhile strategy for preventing sleep apnea. Our findings highlight the importance of diet in managing sleep health and point to vitamin C as a valuable nutrient for those struggling with sleep issues.
Read More
8
We explored how antioxidant therapies, including Vitamin C, can benefit individuals suffering from obstructive sleep apnea (OSA). A systematic review and meta-analysis looked into six studies involving various antioxidants, with the inclusion of Vitamin C among other treatments.
Our findings indicated that Vitamin C, alongside other antioxidants, contributed to improvements in several critical areas. We observed enhancements in endothelial function, which is essential for maintaining healthy blood flow. Additionally, the studies reported significant reductions in markers of oxidative stress and noteworthy improvements in sleep quality indicators.
While Vitamin C was part of the combination therapies assessed, it is essential to note that we cannot draw definitive conclusions about its standalone effectiveness for OSA. The overall positive results call for further exploration in future research to better understand the specific contributions of Vitamin C in treating this condition.
Our findings indicated that Vitamin C, alongside other antioxidants, contributed to improvements in several critical areas. We observed enhancements in endothelial function, which is essential for maintaining healthy blood flow. Additionally, the studies reported significant reductions in markers of oxidative stress and noteworthy improvements in sleep quality indicators.
While Vitamin C was part of the combination therapies assessed, it is essential to note that we cannot draw definitive conclusions about its standalone effectiveness for OSA. The overall positive results call for further exploration in future research to better understand the specific contributions of Vitamin C in treating this condition.
Read More
8
We explored the impact of vitamin C and antioxidant treatment on patients suffering from obstructive sleep apnea syndrome (OSAS). The study involved 20 male patients who first underwent continuous positive airway pressure (CPAP) therapy for two nights. Afterward, they took vitamin C (100 mg twice daily) and vitamin E (400 IU twice daily) for 45 days, followed by another sleep assessment through polysomnography (PSG).
Our findings revealed that oxidative stress seemed to play a significant role in sleep disturbances for OSAS patients. Treatment with vitamin C, alongside vitamin E and CPAP, led to improvements in sleep quality. Patients experienced a decrease in the number of apneic episodes and reported better overall sleep. Notably, there was a reduction in plasma lipid peroxidation and a restoration of reduced glutathione levels.
Even though the study combined various treatments, the data still suggests that antioxidants like vitamin C can bolster sleep quality for those with sleep apnea. Patients spent more time in restorative sleep stages and reported feeling less sleepy during the day.
Overall, while we should consider the combined effects of the treatments, this study highlights potential benefits of vitamin C in enhancing sleep for individuals affected by OSAS—supporting the idea that managing oxidative stress may improve sleep outcomes.
Our findings revealed that oxidative stress seemed to play a significant role in sleep disturbances for OSAS patients. Treatment with vitamin C, alongside vitamin E and CPAP, led to improvements in sleep quality. Patients experienced a decrease in the number of apneic episodes and reported better overall sleep. Notably, there was a reduction in plasma lipid peroxidation and a restoration of reduced glutathione levels.
Even though the study combined various treatments, the data still suggests that antioxidants like vitamin C can bolster sleep quality for those with sleep apnea. Patients spent more time in restorative sleep stages and reported feeling less sleepy during the day.
Overall, while we should consider the combined effects of the treatments, this study highlights potential benefits of vitamin C in enhancing sleep for individuals affected by OSAS—supporting the idea that managing oxidative stress may improve sleep outcomes.
Read More
User Reviews
USERS' SCORE
Good
Based on 3 Reviews
8.4
- All Reviews
- Positive Reviews
- Negative Reviews
9
No more snoring
2 people found this helpful
My husband can snore, but since taking this grape seed supplement, there has been no snoring, allowing me to sleep well.
Read More
7.5
Enhanced alertness
4 people found this helpful
I've been taking this supplement for nearly a year. After starting it, I became more alert and energetic, my complexion improved, and my sleep has also enhanced.
Read More
7.5
Improved sleep quality
I recommend this product as I appreciate the quality and brand. The size is average and the packaging is good and airtight. My sleep has improved significantly, and there is no noticeable taste.
Read More
Frequently Asked Questions
7.5
Enhanced alertness
4 people found this helpful
I've been taking this supplement for nearly a year. After starting it, I became more alert and energetic, my complexion improved, and my sleep has also enhanced.
9
No more snoring
2 people found this helpful
My husband can snore, but since taking this grape seed supplement, there has been no snoring, allowing me to sleep well.
8
We delved into an interesting question: can dietary vitamin C help alleviate sleep apnea? To explore this, we examined data from over 68,000 participants in the UK Biobank and focused on their dietary habits, particularly how much vitamin C they consumed. By using a detailed questionnaire to assess their intake and applying advanced statistical methods, we aimed to uncover any potential connections between vitamin C and sleep disorders, especially sleep apnea.
The results were quite revealing. Participants who consumed higher levels of vitamin C, particularly those in the top intake bracket (around 132.88 to 191.51 mg per day), showed a significant reduction in the risk of developing sleep disorders, including sleep apnea. Specifically, we found that this group had a 25% lower risk of sleep apnea compared to those with lower vitamin C intake.
What's even more encouraging is that this protective effect seemed particularly strong among men and those under 60 years old, suggesting that a sufficient intake of vitamin C could be a worthwhile strategy for preventing sleep apnea. Our findings highlight the importance of diet in managing sleep health and point to vitamin C as a valuable nutrient for those struggling with sleep issues.
The results were quite revealing. Participants who consumed higher levels of vitamin C, particularly those in the top intake bracket (around 132.88 to 191.51 mg per day), showed a significant reduction in the risk of developing sleep disorders, including sleep apnea. Specifically, we found that this group had a 25% lower risk of sleep apnea compared to those with lower vitamin C intake.
What's even more encouraging is that this protective effect seemed particularly strong among men and those under 60 years old, suggesting that a sufficient intake of vitamin C could be a worthwhile strategy for preventing sleep apnea. Our findings highlight the importance of diet in managing sleep health and point to vitamin C as a valuable nutrient for those struggling with sleep issues.
8
We explored how antioxidant therapies, including Vitamin C, can benefit individuals suffering from obstructive sleep apnea (OSA). A systematic review and meta-analysis looked into six studies involving various antioxidants, with the inclusion of Vitamin C among other treatments.
Our findings indicated that Vitamin C, alongside other antioxidants, contributed to improvements in several critical areas. We observed enhancements in endothelial function, which is essential for maintaining healthy blood flow. Additionally, the studies reported significant reductions in markers of oxidative stress and noteworthy improvements in sleep quality indicators.
While Vitamin C was part of the combination therapies assessed, it is essential to note that we cannot draw definitive conclusions about its standalone effectiveness for OSA. The overall positive results call for further exploration in future research to better understand the specific contributions of Vitamin C in treating this condition.
Our findings indicated that Vitamin C, alongside other antioxidants, contributed to improvements in several critical areas. We observed enhancements in endothelial function, which is essential for maintaining healthy blood flow. Additionally, the studies reported significant reductions in markers of oxidative stress and noteworthy improvements in sleep quality indicators.
While Vitamin C was part of the combination therapies assessed, it is essential to note that we cannot draw definitive conclusions about its standalone effectiveness for OSA. The overall positive results call for further exploration in future research to better understand the specific contributions of Vitamin C in treating this condition.
7
Vitamin C may improve endothelial health
We set out to understand the connection between oxidative stress and microvascular endothelial function in people with obstructive sleep apnea (OSA), particularly focusing on the possible benefits of vitamin C treatment. This study involved patients with and without OSA, using medications to measure their endothelial function before and after a vitamin C infusion.
Our findings indicated that endothelial dysfunction is closely linked to increased oxidative stress in OSA patients. When we introduced vitamin C, an antioxidant, we observed improvements in endothelial function. This suggests that oxidative stress plays a significant role in the complications associated with OSA, and that vitamin C may help mitigate some of these effects.
Notably, after six months of continuous positive airway pressure (CPAP) treatment for OSA, we noted further improvements, reinforcing the idea that managing OSA can enhance endothelial health primarily by reducing oxidative stress. However, we acknowledge that while vitamin C showed promise, more controlled studies are needed to fully establish its effects on sleep apnea.
Our findings indicated that endothelial dysfunction is closely linked to increased oxidative stress in OSA patients. When we introduced vitamin C, an antioxidant, we observed improvements in endothelial function. This suggests that oxidative stress plays a significant role in the complications associated with OSA, and that vitamin C may help mitigate some of these effects.
Notably, after six months of continuous positive airway pressure (CPAP) treatment for OSA, we noted further improvements, reinforcing the idea that managing OSA can enhance endothelial health primarily by reducing oxidative stress. However, we acknowledge that while vitamin C showed promise, more controlled studies are needed to fully establish its effects on sleep apnea.
7
We explored the effectiveness of vitamin C as an antioxidant therapy for individuals suffering from obstructive sleep apnea syndrome (OSAS). This review focused on understanding how oxidative stress, a condition where harmful reactive oxygen species accumulate in the body, plays a role in OSAS. It was noted that the cycles of hypoxia and reoxygenation, common in OSAS, lead to this harmful build-up, making antioxidant treatment a potential avenue for relief.
Among various antioxidant agents, vitamin C showed promise in reducing oxidative stress levels. Specific markers like thioredoxin, malondialdehyde, and superoxide dismutase indicated a clear relationship between elevated oxidative stress and sleep apnea. Additionally, studies cited in the review pointed to vitamin C and another antioxidant, N-acetylcysteine (NAC), as potentially beneficial in improving conditions for OSAS patients.
While the findings suggest that vitamin C could be part of a complementary treatment strategy for sleep apnea, the individual effects of vitamin C alone were not fully established. Therefore, while it's an exciting prospect, further research may be needed to entirely understand its impact in isolation.
Among various antioxidant agents, vitamin C showed promise in reducing oxidative stress levels. Specific markers like thioredoxin, malondialdehyde, and superoxide dismutase indicated a clear relationship between elevated oxidative stress and sleep apnea. Additionally, studies cited in the review pointed to vitamin C and another antioxidant, N-acetylcysteine (NAC), as potentially beneficial in improving conditions for OSAS patients.
While the findings suggest that vitamin C could be part of a complementary treatment strategy for sleep apnea, the individual effects of vitamin C alone were not fully established. Therefore, while it's an exciting prospect, further research may be needed to entirely understand its impact in isolation.
8
We explored the impact of vitamin C and antioxidant treatment on patients suffering from obstructive sleep apnea syndrome (OSAS). The study involved 20 male patients who first underwent continuous positive airway pressure (CPAP) therapy for two nights. Afterward, they took vitamin C (100 mg twice daily) and vitamin E (400 IU twice daily) for 45 days, followed by another sleep assessment through polysomnography (PSG).
Our findings revealed that oxidative stress seemed to play a significant role in sleep disturbances for OSAS patients. Treatment with vitamin C, alongside vitamin E and CPAP, led to improvements in sleep quality. Patients experienced a decrease in the number of apneic episodes and reported better overall sleep. Notably, there was a reduction in plasma lipid peroxidation and a restoration of reduced glutathione levels.
Even though the study combined various treatments, the data still suggests that antioxidants like vitamin C can bolster sleep quality for those with sleep apnea. Patients spent more time in restorative sleep stages and reported feeling less sleepy during the day.
Overall, while we should consider the combined effects of the treatments, this study highlights potential benefits of vitamin C in enhancing sleep for individuals affected by OSAS—supporting the idea that managing oxidative stress may improve sleep outcomes.
Our findings revealed that oxidative stress seemed to play a significant role in sleep disturbances for OSAS patients. Treatment with vitamin C, alongside vitamin E and CPAP, led to improvements in sleep quality. Patients experienced a decrease in the number of apneic episodes and reported better overall sleep. Notably, there was a reduction in plasma lipid peroxidation and a restoration of reduced glutathione levels.
Even though the study combined various treatments, the data still suggests that antioxidants like vitamin C can bolster sleep quality for those with sleep apnea. Patients spent more time in restorative sleep stages and reported feeling less sleepy during the day.
Overall, while we should consider the combined effects of the treatments, this study highlights potential benefits of vitamin C in enhancing sleep for individuals affected by OSAS—supporting the idea that managing oxidative stress may improve sleep outcomes.
References
- Zhang Q, Qi X, Wang Z, Zhang D, Wang T. The Association Between Dietary Vitamin C and Sleep Disorders: A Cohort Study Based on UK Biobank. Nutrients. 2024;16. 10.3390/nu16213661
- Boppana TK, Mittal S, Madan K, Tiwari P, Mohan A, et al. Antioxidant therapies for obstructive sleep apnea: A systematic review and meta-analysis. Sleep Breath. 2024;28:1513. 10.1007/s11325-024-03050-z
- Moya EA, Arias P, Iturriaga R. Nitration of MnSOD in the Carotid Body and Adrenal Gland Induced by Chronic Intermittent Hypoxia. J Histochem Cytochem. 2018;66:753. 10.1369/0022155418776229
- Lira AB, de Sousa Rodrigues CF. Evaluation of oxidative stress markers in obstructive sleep apnea syndrome and additional antioxidant therapy: a review article. Sleep Breath. 2016;20:1155. 10.1007/s11325-016-1367-3
- Randolph BJ, Patel HM, Muller MD. Ascorbic acid attenuates the pressor response to voluntary apnea in postmenopausal women. Physiol Rep. 2015;3. 10.14814/phy2.12384
- Celec P, Jurkovičová I, Buchta R, Bartík I, Gardlík R, et al. Antioxidant vitamins prevent oxidative and carbonyl stress in an animal model of obstructive sleep apnea. Sleep Breath. 2013;17:867. 10.1007/s11325-012-0728-9
- Büchner NJ, Quack I, Woznowski M, Stähle C, Wenzel U, et al. Microvascular endothelial dysfunction in obstructive sleep apnea is caused by oxidative stress and improved by continuous positive airway pressure therapy. Respiration. 2011;82:409. 10.1159/000323266
- Cox SE, L'Esperance V, Makani J, Soka D, Hill CM, et al. Nocturnal haemoglobin oxygen saturation variability is associated with vitamin C deficiency in Tanzanian children with sickle cell anaemia. Acta Paediatr. 2011;100:594. 10.1111/j.1651-2227.2010.02078.x
- Singh TD, Patial K, Vijayan VK, Ravi K. Oxidative stress and obstructive sleep apnoea syndrome. Indian J Chest Dis Allied Sci. 2009;51:217.
- Del Rio R, Moya EA, Iturriaga R. Carotid body and cardiorespiratory alterations in intermittent hypoxia: the oxidative link. Eur Respir J. 2010;36:143. 10.1183/09031936.00158109
- Grebe M, Eisele HJ, Weissmann N, Schaefer C, Tillmanns H, et al. Antioxidant vitamin C improves endothelial function in obstructive sleep apnea. Am J Respir Crit Care Med. 2006;173:897.
