Overview

SCIENTIFIC SCORE
Moderately Effective
Based on 12 Researches
8.1
USERS' SCORE
Good
Based on 143 Reviews
8.9
Supplement Facts
Serving Size: 1 Softgel
Amount Per Serving
%DV
Vitamin D3 (as Cholecalciferol) (from Lanolin)
50 mcg (2,000 IU)
250%

Top Medical Research Studies

8
Vitamin D3 improves cold symptoms
We conducted a thorough investigation into how 25-hydroxyvitamin D3, commonly referred to as vitamin D3, impacts upper respiratory tract infections (URTIs), particularly the common cold. This study was carried out as a randomized, double-blind, placebo-controlled trial, engaging 428 participants, all aged between 45 and 74, across three clinics in Japan.

Participants were divided into two groups, with one receiving a daily dose of 10 μg of vitamin D3, while the other took a placebo for 16 weeks. Our findings highlighted that those who took vitamin D3 experienced a reduction in the duration of their upper respiratory symptoms, as well as a decrease in severity and improvement in their quality of life during illness.

Overall, our results indicate that supplementing with vitamin D3 might be a proactive step in handling the discomforts associated with common colds. This simple addition to one's daily routine could lead to a notably better experience when facing URTIs, providing a hopeful outlook for those looking for relief from their symptoms.
Read More
We explored the connection between vitamin D levels and the frequency of upper respiratory tract infections (URTI) in physically active individuals throughout different seasons. In our research, we observed over 1,600 military recruits during their basic training, noting that only 21% were vitamin D sufficient during winter. Alarmingly, those who had sufficient vitamin D levels were found to be 40% less likely to experience URTIs compared to their deficient counterparts, suggesting that maintaining adequate vitamin D may be crucial for better respiratory health during demanding training periods.

Building on these findings, we conducted a follow-up study with 250 recruits, where we implemented various vitamin D supplementation strategies. Participants received either a placebo, simulated sunlight exposure, or oral vitamin D3 supplementation. The results were promising: vitamin D helped alleviate the severity of URTI symptoms and significantly reduced the number of days experiencing a cold. Notably, both sunlight and dietary supplementation were equally effective in boosting vitamin D levels and improving outcomes.

Overall, achieving vitamin D sufficiency can markedly reduce the burden of URTIs, particularly in physically demanding scenarios such as military training.
Read More
8
Vitamin D3 aids cold recovery
We explored whether taking 25-hydroxyvitamin D3, a form of vitamin D, could have a positive impact on upper respiratory tract infections (URTIs), commonly known as colds. To do this, we conducted a randomized, double-blind, placebo-controlled study at clinics in Japan, involving 428 participants aged between 45 and 74 years.

Participants were divided into two groups: one received a daily dose of 10 micrograms of vitamin D3, while the other group received a placebo for 16 weeks. We monitored the frequency of URTIs, their severity, the participants’ quality of life, and the duration of the infections.

Our findings revealed that those who took vitamin D3 experienced shorter durations of URTIs, less severe symptoms, and better quality of life during their illness compared to those on the placebo. This suggests that vitamin D3 may help mitigate the discomfort associated with colds and potentially make us feel better more quickly when we are sick.
Read More

Most Useful Reviews

9.5
Reduced illness frequency
This vitamin is essential for everyone, particularly for bolstering my immune system. I used to get sick frequently, especially from public transport. Since my daughter and I started taking vitamin D-3 regularly, we've both noticed a significant reduction in the common cold.
Read More
9.5
No colds experienced
These wonderful vitamins come in small capsules and are taken just once a day. After four months of use, I have not had a single hint of the common cold or fatigue.
Read More
8.8
Prevented colds
The composition of this complex, which includes mushrooms and green tea, is excellent. I take it at the first sign of a cold, but not on an empty stomach as it causes slight nausea. I took one capsule twice daily and paired it with Epicor for a better defence against colds.
Read More

Medical Researches

SCIENTIFIC SCORE
Moderately Effective
Based on 12 Researches
8.1
  • All Researches
We delved into the question of how vitamin D3 supplementation might influence occurrences of the common cold, particularly among athletes. There is growing interest within the sports nutrition community about whether certain nutrients can help maintain a healthy immune response during periods of intense physical training.

Our findings suggest that vitamin D3 is particularly important for immune function. Various studies indicate that adequate levels of vitamin D can assist in reducing the incidence and duration of infections, including colds, not just in athletes but in the general population, too. However, many individuals may experience low vitamin D levels, especially during the winter months when sunlight exposure is limited.

While the overall evidence suggests a beneficial role for vitamin D in immune health, we recognize that direct evidence specifically linking vitamin D3 to a reduction in the common cold is somewhat limited. Nonetheless, the importance of maintaining sufficient vitamin D status can't be overlooked in the broader context of overall health and resilience against infections.

In conclusion, while vitamin D3 shows promise in boosting our immunity, further focused research specifically addressing its impact on the common cold is needed for clearer insights.
Read More
9
Vitamin D3 shows potential benefits
We explored the potential benefits of a special combination of micronutrients, which includes vitamin D3, in helping individuals who frequently suffer from upper respiratory tract infections, commonly known as the common cold. This study involved 192 participants and was conducted as a randomized, placebo-controlled, double-blind trial over 16 weeks.

Our findings were promising, revealing that those in the group receiving the micronutrient blend reported significant improvements in their cold symptoms compared to those who received a placebo. Specifically, individuals with severe symptoms showed a notable reduction in their common cold scores, indicating that vitamin D3, along with other vitamins and minerals, could play a role in enhancing overall immune response.

Furthermore, younger participants in the active group were less likely to miss work due to cold episodes. Those who had low levels of vitamin D3 or vitamin C at the start of the study also experienced fewer episodes of illness, underscoring the importance of maintaining adequate levels of these nutrients.

While there was no isolated analysis of vitamin D3’s effectiveness, the overall improvement in the group suggests that this micronutrient, among others, could truly contribute to better health during cold season.
Read More
We explored the connection between vitamin D levels and the frequency of upper respiratory tract infections (URTI) in physically active individuals throughout different seasons. In our research, we observed over 1,600 military recruits during their basic training, noting that only 21% were vitamin D sufficient during winter. Alarmingly, those who had sufficient vitamin D levels were found to be 40% less likely to experience URTIs compared to their deficient counterparts, suggesting that maintaining adequate vitamin D may be crucial for better respiratory health during demanding training periods.

Building on these findings, we conducted a follow-up study with 250 recruits, where we implemented various vitamin D supplementation strategies. Participants received either a placebo, simulated sunlight exposure, or oral vitamin D3 supplementation. The results were promising: vitamin D helped alleviate the severity of URTI symptoms and significantly reduced the number of days experiencing a cold. Notably, both sunlight and dietary supplementation were equally effective in boosting vitamin D levels and improving outcomes.

Overall, achieving vitamin D sufficiency can markedly reduce the burden of URTIs, particularly in physically demanding scenarios such as military training.
Read More
8
Vitamin D’s role in cold prevention
We examined the role of vitamin D in managing common colds, delving into how it interacts with our immune system to potentially lessen the severity and duration of symptoms. The study highlighted that individuals with vitamin D deficiency, as well as those not receiving large doses, are more likely to benefit from vitamin D supplementation during cold episodes.

Findings suggest that vitamin D might act as a protective agent against common colds overall. Taking vitamin D regularly could help fortify our immune response, which plays a crucial part in fighting off the viruses responsible for colds. The research points towards the idea that maintaining adequate vitamin D levels may offer significant advantages for keeping our immune system vigilant.

However, it’s essential to approach this information with a measure of caution, as further research is necessary to draw definitive conclusions. Overall, encouraging patients to consider vitamin D as a part of their cold prevention strategy seems promising.
Read More
8
Vitamin D3 aids cold recovery
We explored whether taking 25-hydroxyvitamin D3, a form of vitamin D, could have a positive impact on upper respiratory tract infections (URTIs), commonly known as colds. To do this, we conducted a randomized, double-blind, placebo-controlled study at clinics in Japan, involving 428 participants aged between 45 and 74 years.

Participants were divided into two groups: one received a daily dose of 10 micrograms of vitamin D3, while the other group received a placebo for 16 weeks. We monitored the frequency of URTIs, their severity, the participants’ quality of life, and the duration of the infections.

Our findings revealed that those who took vitamin D3 experienced shorter durations of URTIs, less severe symptoms, and better quality of life during their illness compared to those on the placebo. This suggests that vitamin D3 may help mitigate the discomfort associated with colds and potentially make us feel better more quickly when we are sick.
Read More

User Reviews

USERS' SCORE
Good
Based on 143 Reviews
8.9
  • All Reviews
  • Positive Reviews
  • Negative Reviews
9.5
Reduced illness frequency
This vitamin is essential for everyone, particularly for bolstering my immune system. I used to get sick frequently, especially from public transport. Since my daughter and I started taking vitamin D-3 regularly, we've both noticed a significant reduction in the common cold.
Read More
9.5
No colds experienced
These wonderful vitamins come in small capsules and are taken just once a day. After four months of use, I have not had a single hint of the common cold or fatigue.
Read More
8.8
Prevented colds
The composition of this complex, which includes mushrooms and green tea, is excellent. I take it at the first sign of a cold, but not on an empty stomach as it causes slight nausea. I took one capsule twice daily and paired it with Epicor for a better defence against colds.
Read More
9.5
No colds experienced
These vitamins are amazing! I take small capsules just once a day. After four months, I’ve experienced no common cold or fatigue.
Read More
9.5
Combat common cold
Excellent D3 from a top brand. During cold seasons, it not only replenishes essential vitamins and minerals but also helps in fighting viruses and bacteria effectively.
Read More

Frequently Asked Questions

The common cold is a viral infection of the upper respiratory tract, primarily affecting the nose and throat. It's caused by a variety of viruses, with rhinoviruses being the most prevalent. Symptoms generally include a runny or stuffy nose, sore throat, cough, sneezing, mild headache, and sometimes a low-grade fever. While the common cold is often mild and resolves on its own within a week or two, it can still be bothersome and impact daily activities.

Transmission occurs through respiratory droplets when an infected person coughs or sneezes, or by touching surfaces contaminated with the virus. Preventative measures include frequent handwashing, using hand sanitizer, and avoiding close contact with infected individuals. Since there is currently no cure for the common cold, treatment focuses on symptom relief through over-the-counter medications, adequate rest, and hydration. While colds may be uncomfortable, they are generally not serious; however, seeking medical attention may be necessary if symptoms worsen or persist for an extended period.

Vitamin D is a fat-soluble vitamin that's essential for maintaining healthy bones and teeth, supporting immune system function, and facilitating normal cell growth and development. It plays a crucial role in calcium absorption in the gut, which is vital for bone health. Unlike most vitamins, our bodies can produce Vitamin D when exposed to sunlight, specifically UVB rays, which is why it’s often referred to as the "sunshine vitamin." However, depending on your geographical location, lifestyle, and skin type, getting sufficient Vitamin D from the sun alone can be challenging, particularly during the winter months.

In addition to sunlight, Vitamin D can be obtained from certain foods such as fatty fish (like salmon and mackerel), fish liver oils, and fortified foods like milk and cereals. Some individuals may also consider supplements, especially if they're at risk for deficiency. Insufficient vitamin D levels are linked to various health issues, including rickets in children, osteomalacia in adults, and even an increased risk of chronic diseases. Regularly checking your vitamin D levels and consulting with a healthcare professional can help ensure you're meeting your needs for optimal health.

While the role of Vitamin D in immune function is well-established, particularly its potential to enhance innate immunity, the evidence linking Vitamin D supplementation specifically to the prevention or treatment of the common cold is still not conclusive. Some studies suggest that adequate levels of Vitamin D may reduce the incidence of respiratory infections, including colds, particularly in individuals who are deficient in this essential nutrient. For example, individuals with lower Vitamin D levels may have a higher risk of upper respiratory tract infections.

However, other research has not found a distinctive benefit from Vitamin D in preventing or reducing the severity of colds for the general population. It is important to note that while Vitamin D can play a role in bolstering overall immune health, relying solely on it to prevent the common cold is not advisable. A balanced diet, proper hygiene, and other preventive measures remain crucial in managing common colds. If you're considering Vitamin D supplementation, it’s always best to consult with a healthcare professional.

Based on user reviews, the timeframe for seeing results from vitamin D supplements for the common cold can vary significantly. Some users report experiencing a noticeable improvement in their immunity and a reduction in common cold symptoms within just a few days of starting the supplement. For instance, one user stated, "After just a few days of taking it, I felt revitalised and my immune system improved significantly" (Read Review).

While others mention a longer duration before seeing substantial benefits. For example, a user noted that after taking the supplements for four months, they had not experienced any signs of the common cold (Read Review). Overall, users suggest that while some may feel improvements relatively quickly, others might need several weeks to months of regular intake to notice a significant difference in their immunity against common colds.

Vitamin D supplementation is gaining attention for its potential benefits in managing symptoms associated with the common cold. Studies suggest that adequate intake of vitamin D can significantly mitigate the severity of cold symptoms, particularly nasal issues such as runny nose and congestion. In one study involving 428 participants, those who took vitamin D3 reported shorter durations and milder symptoms during upper respiratory infections compared to those on a placebo, indicating that vitamin D could enhance quality of life during colds [9]. Similarly, research has shown that military recruits with sufficient vitamin D levels were less likely to experience upper respiratory tract infections by 40%, highlighting the importance of maintaining adequate vitamin D levels for respiratory health [1].

However, while vitamin D appears to alleviate symptoms, it may not prevent colds or significantly reduce the frequency of infections. Some studies noted no substantial difference in the total number of cold episodes between those taking vitamin D and those not, suggesting it may be more of a supportive therapy rather than a definitive preventive measure [8]. Therefore, while there are promising insights into the role of vitamin D in managing cold symptoms, especially in individuals with low levels of the vitamin, further research is necessary to fully understand its benefits and contributions to overall immune health.

Based on user reviews, many individuals have reported commendable improvements in their immunity and a significant reduction in the frequency and severity of common cold symptoms after incorporating vitamin D supplements into their routines. For example, one user noticed a marked decrease in cold occurrences, stating, "Since my daughter and I started taking vitamin D-3 regularly, we've both noticed a significant reduction in the common cold" (Read Review). Others have shared longer-term success, such as a user who has taken the supplement for four months without a single cold or fatigue (Read Review).

Several users emphasized that vitamin D has not only bolstered their immunity but also positively impacted their overall health, including mood and energy levels. For instance, one reviewer noted, "It has significantly improved my mood, energy levels, and immunity" (Read Review). Another confirmed that since starting vitamin D, they haven't experienced a common cold, stating, "I’ve been taking it for about two months now and haven't had a single cold since" (Read Review). It is important to note that individual results can vary; while many have seen substantial improvements, others might experience different effects based on their unique health circumstances.

Users report positive experiences when combining vitamin D supplements with other supplements for managing the common cold. One user highlighted that they take vitamin D alongside Epicor, emphasizing that this combination enhances their defenses against colds (Read Review). Additionally, another reviewer noted a specific regimen of vitamin D, zinc, and vitamin C, which they found effective in speeding up their recovery from the common cold (Read Review).

Moreover, users frequently mention pairing vitamin D with omega-3 supplements, which they believe maximizes absorption and boosts overall immune response during cold seasons. For example, one individual stated that combining vitamin D with omega-3 has not only improved their immunity but also helped prevent seasonal depression, enhancing their overall well-being (Read Review). This trend underscores a broader strategy among users to bolster their defenses against colds through a multi-supplement approach, reflecting a collective belief in the synergistic benefits of combining various nutrients for improved health outcomes.

When it comes to using Vitamin D to treat common colds, research indicates that a daily dose of 10 micrograms (µg) can be beneficial. In studies involving participants with low vitamin D levels, supplementation with this amount not only alleviated the severity of cold symptoms but also reduced the duration of infections and improved quality of life during illness [9]. For instance, one study found that participants who received Vitamin D3 experienced shorter durations of upper respiratory tract infections (URTIs), leading to less severe symptoms [9].

Additionally, achieving sufficient Vitamin D levels may significantly decrease the risk of upper respiratory infections overall. Individuals who were vitamin D deficient prior to supplementation were particularly likely to experience improvements in their symptoms [3]. With both dietary sources and sunlight as effective means of boosting Vitamin D, maintaining adequate levels appears crucial for enhancing immune function and combating the discomfort associated with common colds [1]. Thus, considering a daily intake of 10 µg of Vitamin D may be a practical strategy for those looking to fend off the common cold more effectively.

9.5
Rapid recovery
Just before starting this vitamin, I had the worst common cold. After just a few days of taking it, I felt revitalised and my immune system improved significantly. It has provided lasting effects and requires fewer pills than other supplements!
9.5
No colds experienced
These wonderful vitamins come in small capsules and are taken just once a day. After four months of use, I have not had a single hint of the common cold or fatigue.
9.5
Reduced illness frequency
This vitamin is essential for everyone, particularly for bolstering my immune system. I used to get sick frequently, especially from public transport. Since my daughter and I started taking vitamin D-3 regularly, we've both noticed a significant reduction in the common cold.
9.5
Life-changing experience
I'm thrilled to have discovered this vitamin. It has significantly improved my mood, energy levels, and immunity, helping me resist common colds. I highly recommend it!
9.5
No more colds
Typically, I avoid supplements, but after suffering from a bad common cold and dizziness, I gave this vitamin a go. I've been taking it for about two months now and haven't had a single cold since, plus my energy levels are at their best!
8.8
Prevented colds
The composition of this complex, which includes mushrooms and green tea, is excellent. I take it at the first sign of a cold, but not on an empty stomach as it causes slight nausea. I took one capsule twice daily and paired it with Epicor for a better defence against colds.
4.5
Immune health strategy
I always keep vitamin D in my medicine cabinet! For a cold, my method is simple: vitamin D 10000 IU, zinc, and vitamin C. Drink plenty of water: this approach aids in recovering from the common cold quickly. If helpful, please respond YES! Thank you!
9.5
Prevented colds
Wonderful! The small capsules are easy to swallow. Taking them after breakfast with omega-3 has made waking up easier and prevented me from catching common colds. I previously suffered from respiratory infections frequently, but I no longer face seasonal depression or fatigue.
8
Vitamin D3 improves cold symptoms
We conducted a thorough investigation into how 25-hydroxyvitamin D3, commonly referred to as vitamin D3, impacts upper respiratory tract infections (URTIs), particularly the common cold. This study was carried out as a randomized, double-blind, placebo-controlled trial, engaging 428 participants, all aged between 45 and 74, across three clinics in Japan.

Participants were divided into two groups, with one receiving a daily dose of 10 μg of vitamin D3, while the other took a placebo for 16 weeks. Our findings highlighted that those who took vitamin D3 experienced a reduction in the duration of their upper respiratory symptoms, as well as a decrease in severity and improvement in their quality of life during illness.

Overall, our results indicate that supplementing with vitamin D3 might be a proactive step in handling the discomforts associated with common colds. This simple addition to one's daily routine could lead to a notably better experience when facing URTIs, providing a hopeful outlook for those looking for relief from their symptoms.
We explored the connection between vitamin D levels and the frequency of upper respiratory tract infections (URTI) in physically active individuals throughout different seasons. In our research, we observed over 1,600 military recruits during their basic training, noting that only 21% were vitamin D sufficient during winter. Alarmingly, those who had sufficient vitamin D levels were found to be 40% less likely to experience URTIs compared to their deficient counterparts, suggesting that maintaining adequate vitamin D may be crucial for better respiratory health during demanding training periods.

Building on these findings, we conducted a follow-up study with 250 recruits, where we implemented various vitamin D supplementation strategies. Participants received either a placebo, simulated sunlight exposure, or oral vitamin D3 supplementation. The results were promising: vitamin D helped alleviate the severity of URTI symptoms and significantly reduced the number of days experiencing a cold. Notably, both sunlight and dietary supplementation were equally effective in boosting vitamin D levels and improving outcomes.

Overall, achieving vitamin D sufficiency can markedly reduce the burden of URTIs, particularly in physically demanding scenarios such as military training.
8
Vitamin D helps reduce cold symptoms
We conducted an insightful analysis to see how 25-hydroxyvitamin D, often referred to as 25OHD, impacts symptoms of upper respiratory tract infections, commonly known as colds. In this randomized, placebo-controlled study, participants with insufficient or deficient levels of vitamin D were given either a daily dose of 10 µg of 25OHD or a placebo over a period of 16 weeks. This setup allowed us to objectively compare the effects of vitamin D treatment.

Our findings were quite telling. We observed that those receiving 25OHD had significantly lower scores for physical symptoms such as runny nose, sneezing, and head congestion compared to the placebo group. Additionally, quality of life scores improved across the board for the vitamin D group, with the exception of one aspect—breathing easily.

However, it's important to note that while 25OHD intake seemed to alleviate some symptoms, there was no significant difference in the overall number of cold episodes experienced or the usage of medications like antibiotics and pain relievers. This suggests that while 25-hydroxyvitamin D can help reduce certain nasal symptoms and improve quality of life, it may not prevent colds or decrease their frequency.
8
Vitamin D’s role in cold prevention
We examined the role of vitamin D in managing common colds, delving into how it interacts with our immune system to potentially lessen the severity and duration of symptoms. The study highlighted that individuals with vitamin D deficiency, as well as those not receiving large doses, are more likely to benefit from vitamin D supplementation during cold episodes.

Findings suggest that vitamin D might act as a protective agent against common colds overall. Taking vitamin D regularly could help fortify our immune response, which plays a crucial part in fighting off the viruses responsible for colds. The research points towards the idea that maintaining adequate vitamin D levels may offer significant advantages for keeping our immune system vigilant.

However, it’s essential to approach this information with a measure of caution, as further research is necessary to draw definitive conclusions. Overall, encouraging patients to consider vitamin D as a part of their cold prevention strategy seems promising.

References

  1. Harrison SE, Oliver SJ, Kashi DS, Carswell AT, Edwards JP, et al. Influence of Vitamin D Supplementation by Simulated Sunlight or Oral D3 on Respiratory Infection during Military Training. Med Sci Sports Exerc. 2021;53:1505. doi:10.1249/MSS.0000000000002604
  2. Shimizu Y, Ito Y, Uotsu N, Yui K. Intake of 25-Hydroxyvitamin D May Reduce the Severity of Upper Respiratory Tract Infection: Post hoc Analysis of a Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study. Nutrients. 2020;12. doi:10.3390/nu12123769
  3. Rondanelli M, Miccono A, Lamburghini S, Avanzato I, Riva A, et al. Self-Care for Common Colds: The Pivotal Role of Vitamin D, Vitamin C, Zinc, and in Three Main Immune Interactive Clusters (Physical Barriers, Innate and Adaptive Immunity) Involved during an Episode of Common Colds-Practical Advice on Dosages and on the Time to Take These Nutrients/Botanicals in order to Prevent or Treat Common Colds. Evid Based Complement Alternat Med. 2018;2018:5813095. doi:10.1155/2018/5813095
  4. Shimizu Y, Ito Y, Yui K, Egawa K, Orimo H. Intake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study. J Nutr Health Aging. 2018;22:491. doi:10.1007/s12603-017-0952-x
  5. Gleeson M. Immunological aspects of sport nutrition. Immunol Cell Biol. 2016;94:117. doi:10.1038/icb.2015.109
  6. Schmidt K, Zirkler S. [Dietary efficacy of a micronutrient combination in patients with recurrent upper respiratory tract infections. Results of a placebo-controlled double-blind study]. MMW Fortschr Med. 2011;153 Suppl 3:83.
  7. Schmidt K, Zirkler S. [Dietary efficacy of a micronutrient combination in patients with recurrent upper respiratory tract infections. Results of a placebo-controlled doubleblind study.]. MMW Fortschr Med. 2011;153:83. doi:10.1007/s15006-011-1630-2
  8. Shimizu Y, Ito Y, Uotsu N, Yui K. Intake of 25-Hydroxyvitamin D May Reduce the Severity of Upper Respiratory Tract Infection: Post hoc Analysis of a Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study. Nutrients. 2020;12. doi:10.3390/nu12123769
  9. Shimizu Y, Ito Y, Yui K, Egawa K, Orimo H. Intake of 25-Hydroxyvitamin D3 Reduces Duration and Severity of Upper Respiratory Tract Infection: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Comparison Study. J Nutr Health Aging. 2018;22:491. doi:10.1007/s12603-017-0952-x
  10. Gleeson M. Immunological aspects of sport nutrition. Immunol Cell Biol. 2016;94:117. doi:10.1038/icb.2015.109
  11. Schmidt K, Zirkler S. [Dietary efficacy of a micronutrient combination in patients with recurrent upper respiratory tract infections. Results of a placebo-controlled double-blind study]. MMW Fortschr Med. 2011;153 Suppl 3:83.
  12. Schmidt K, Zirkler S. [Dietary efficacy of a micronutrient combination in patients with recurrent upper respiratory tract infections. Results of a placebo-controlled doubleblind study.]. MMW Fortschr Med. 2011;153:83. doi:10.1007/s15006-011-1630-2
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