Last update
5/26/2025
Research Authors

Overview

SCIENTIFIC SCORE
Moderately Effective
Based on 2 Researches
8
USERS' SCORE
Good
Based on 178 Reviews
8.2
Supplement Facts
Serving Size: One Capsule
Amount Per Serving
%DV
One Capsule Contains:
Amount Per Serving
% DV
Vitamin C (as Ascorbic Acid)
500 mg
556%
Citrus Bioflavonoids
75 mg
*

Top Medical Research Studies

7
We explored the effects of vitamin C on the common cold and pneumonia by examining a range of studies. Interestingly, research on animals suggests that vitamin C may have protective effects against infections. However, when it comes to preventing colds in the general population, taking more than 1 gram of vitamin C per day didn’t show significant benefits.

But there's a twist! Participants engaged in heavy physical activities saw their cold incidence reduced by half with vitamin C supplementation. Additionally, regular intake of 1 gram or more daily was linked to a 15% decrease in cold severity. While some therapeutic trials showed inconsistent results when vitamin C was taken after cold symptoms appeared, two studies did indicate that larger doses (6-8 grams per day) could effectively shorten the duration of colds compared to lower doses.

Our investigation also looked into pneumonia, but the studies were conducted in unique settings, such as a boarding school and military recruits. This makes it hard to generalize the findings to the wider population. Yet, some trials suggested benefits for pneumonia patients. Finally, the role of vitamin C in treating COVID-19 and sepsis remains unclear, with mixed results.

Given that vitamin C seems to alleviate symptoms and shorten the duration of colds, while being safe and affordable, it might be worth considering a dose of 6-8 grams per day to see if it helps at an individual level.
Read More
9
Vitamin C improves cold tolerance
We explored the effects of ascorbic acid, commonly known as vitamin C, on cold tolerance in tomato seedlings. In our study, we discovered that applying vitamin C significantly boosts the seedlings' ability to handle cold stress.

By enhancing the antioxidant defense system, vitamin C treatment increased the enzyme activity in the seedlings' leaves. Additionally, it raised levels of important compounds such as proline, sugar, and abscisic acid, all of which play crucial roles in plant stress responses.

Our observations showed that vitamin C also protects the photosynthesis system of tomato seedlings. This implies that it helps maintain chlorophyll function, which is critical for the plant's overall health, especially under cold conditions.

Moreover, we found that vitamin C treatments led to increased expression of genes linked to antioxidant enzymes and cold response mechanisms. Overall, our findings suggest that exogenous vitamin C is a beneficial approach to improve cold tolerance in tomatoes and may provide helpful insights for farmers looking to cultivate hardier varieties during colder months.
Read More

Most Useful Reviews

10
Instant cold relief
18 people found this helpful
Super product! At the first sign of a cold, it works 100%. I highly recommend it!
Read More
9
Quick recovery
4 people found this helpful
I liked that this product was well tolerated with no side effects. I even gave it to my 12-year-old daughter during her illness, and she recovered swiftly from the cold.
Read More
7.5
Helps illness subside
2 people found this helpful
Great product! During the cold season, it helps tremendously. At the slightest signs of illness, I take two tablets daily with plenty of water, and the disease subsides.
Read More

Medical Researches

SCIENTIFIC SCORE
Moderately Effective
Based on 2 Researches
8
  • All Researches
9
Vitamin C improves cold tolerance
We explored the effects of ascorbic acid, commonly known as vitamin C, on cold tolerance in tomato seedlings. In our study, we discovered that applying vitamin C significantly boosts the seedlings' ability to handle cold stress.

By enhancing the antioxidant defense system, vitamin C treatment increased the enzyme activity in the seedlings' leaves. Additionally, it raised levels of important compounds such as proline, sugar, and abscisic acid, all of which play crucial roles in plant stress responses.

Our observations showed that vitamin C also protects the photosynthesis system of tomato seedlings. This implies that it helps maintain chlorophyll function, which is critical for the plant's overall health, especially under cold conditions.

Moreover, we found that vitamin C treatments led to increased expression of genes linked to antioxidant enzymes and cold response mechanisms. Overall, our findings suggest that exogenous vitamin C is a beneficial approach to improve cold tolerance in tomatoes and may provide helpful insights for farmers looking to cultivate hardier varieties during colder months.
Read More
7
We explored the effects of vitamin C on the common cold and pneumonia by examining a range of studies. Interestingly, research on animals suggests that vitamin C may have protective effects against infections. However, when it comes to preventing colds in the general population, taking more than 1 gram of vitamin C per day didn’t show significant benefits.

But there's a twist! Participants engaged in heavy physical activities saw their cold incidence reduced by half with vitamin C supplementation. Additionally, regular intake of 1 gram or more daily was linked to a 15% decrease in cold severity. While some therapeutic trials showed inconsistent results when vitamin C was taken after cold symptoms appeared, two studies did indicate that larger doses (6-8 grams per day) could effectively shorten the duration of colds compared to lower doses.

Our investigation also looked into pneumonia, but the studies were conducted in unique settings, such as a boarding school and military recruits. This makes it hard to generalize the findings to the wider population. Yet, some trials suggested benefits for pneumonia patients. Finally, the role of vitamin C in treating COVID-19 and sepsis remains unclear, with mixed results.

Given that vitamin C seems to alleviate symptoms and shorten the duration of colds, while being safe and affordable, it might be worth considering a dose of 6-8 grams per day to see if it helps at an individual level.
Read More

User Reviews

USERS' SCORE
Good
Based on 178 Reviews
8.2
  • All Reviews
  • Positive Reviews
  • Negative Reviews
10
Instant cold relief
18 people found this helpful
Super product! At the first sign of a cold, it works 100%. I highly recommend it!
Read More
9
Quick recovery
4 people found this helpful
I liked that this product was well tolerated with no side effects. I even gave it to my 12-year-old daughter during her illness, and she recovered swiftly from the cold.
Read More
7.5
Helps illness subside
2 people found this helpful
Great product! During the cold season, it helps tremendously. At the slightest signs of illness, I take two tablets daily with plenty of water, and the disease subsides.
Read More
10
Cold passes by
1 people found this helpful
This product works 100%! Previously, I took another vitamin C powder, but this form is more convenient with added flavonoids. When family members fall ill, I administer this vitamin, and the cold passes quickly. I will continue taking it and recommend it to everyone.
Read More
10
Works for symptoms
1 people found this helpful
Vitamin C is simply irreplaceable at the first symptoms of a cold; it works 100%.
Read More

Frequently Asked Questions

9
Quick recovery
This vitamin worked wonders for my cold. Shortly after taking it, my nasal discharge cleared, I felt better instantly, and it aided in a swift recovery. Thorne is high-quality, with no impact on my stomach—everything is perfect!
9
Essential for colds
1 people found this helpful
Vitamin C is an irreplaceable supplement in my medicine cabinet. At the first signs of a cold, I take 1000 mg, vitamin D3, and zinc. In the morning, you feel all the symptoms vanish. I recommend it!
10
Works for symptoms
1 people found this helpful
Vitamin C is simply irreplaceable at the first symptoms of a cold; it works 100%.
9
Quick recovery
4 people found this helpful
I liked that this product was well tolerated with no side effects. I even gave it to my 12-year-old daughter during her illness, and she recovered swiftly from the cold.
9
Reduced cold frequency
Excellent! I searched for a quality vitamin C supplement and decided to try Thorne's Vitamin C with Flavonoids. This indispensable product not only provides vitamin C but also flavonoids, which enhance its effect and support the immune system. Since I began taking it, I’ve had fewer colds, and my skin looks healthier. These capsules are easy to swallow, and the noticeable effect has improved my overall well-being and energy levels.
10
Cold passes by
1 people found this helpful
This product works 100%! Previously, I took another vitamin C powder, but this form is more convenient with added flavonoids. When family members fall ill, I administer this vitamin, and the cold passes quickly. I will continue taking it and recommend it to everyone.
9
Cold passes faster
1 people found this helpful
I drink vitamin C nearly daily, as I have vascular meshes on my legs and often take collagen, which is well absorbed together. When I feel a cold beginning, I take vitamin C, zinc, quercetin, and vitamin D—a wonderful combination that works; the cold often passes easily and more quickly, sometimes it doesn't come at all. Therefore, vitamin C is essential for every housewife.
7
We explored the effects of vitamin C on the common cold and pneumonia by examining a range of studies. Interestingly, research on animals suggests that vitamin C may have protective effects against infections. However, when it comes to preventing colds in the general population, taking more than 1 gram of vitamin C per day didn’t show significant benefits.

But there's a twist! Participants engaged in heavy physical activities saw their cold incidence reduced by half with vitamin C supplementation. Additionally, regular intake of 1 gram or more daily was linked to a 15% decrease in cold severity. While some therapeutic trials showed inconsistent results when vitamin C was taken after cold symptoms appeared, two studies did indicate that larger doses (6-8 grams per day) could effectively shorten the duration of colds compared to lower doses.

Our investigation also looked into pneumonia, but the studies were conducted in unique settings, such as a boarding school and military recruits. This makes it hard to generalize the findings to the wider population. Yet, some trials suggested benefits for pneumonia patients. Finally, the role of vitamin C in treating COVID-19 and sepsis remains unclear, with mixed results.

Given that vitamin C seems to alleviate symptoms and shorten the duration of colds, while being safe and affordable, it might be worth considering a dose of 6-8 grams per day to see if it helps at an individual level.

References

  1. Hemilä H, Chalker E. Vitamin C for the common cold and pneumonia. Pol Arch Intern Med. 2025;135. 10.20452/pamw.16926
  2. Wang X, Ran C, Fu Y, Han L, Yang X, et al. Application of Exogenous Ascorbic Acid Enhances Cold Tolerance in Tomato Seedlings through Molecular and Physiological Responses. Int J Mol Sci. 2024;25. 10.3390/ijms251810093
image