SCIENTIFIC SCORE
Possibly Effective
Based on 5 Researches
7.2
USERS' SCORE
Good
Based on 17 Reviews
8.8
Supplement Facts
Serving Size: 1 Vegetarian Tablet
Amount Per Serving
%DV
Vitamin C (as Ester-C® Calcium Ascorbate)
1,000 mg (1 g)
1,111%
Calcium (as Ester-C® Calcium Ascorbate)
108 mg
8%
Citrus Bioflavonoids ComplexCitrus Bioflavonoids (Citrus spp.) (fruit), Sweet Orange, Tangerine, Lime, Lemon, Acerola, Rutin, Hesperidin Complex (Citrus spp.) (fruit), Naturally Occurring Vitamin C Metabolites
200 mg
**

Top Medical Research Studies

8
Vitamin C mitigates flu pneumonia
A new mechanism of vitamin C effects on A/FM/1/47(H1N1) virus-induced pneumonia in restraint-stressed mice.
Highly relevant study findings
We examined the effects of vitamin C on pneumonia caused by the influenza virus, specifically the H1N1 strain, in mice under stress. The study found that when exposed to restraint stress, the mice experienced increased mortality and more severe pneumonia symptoms.

However, by giving them oral vitamin C at doses of 125 and 250 mg/kg, we observed a significant reduction in these severe outcomes. Vitamin C seemed to modulate the expression of certain genes related to the immune response, such as MAVS and IRF3, and increased the expression of NF-κB, which plays a key role in the body's antiviral defense.

Our research suggested that vitamin C's protective effects might stem from its ability to inhibit excess cortisol production in the adrenal gland, which is often elevated due to stress. By lowering cortisol levels, vitamin C may help reduce susceptibility to influenza infections, making it a potential ally during the flu season, especially for those experiencing stress.

Through these findings, we highlighted a new mechanism for how vitamin C can be beneficial during influenza infections, particularly for those who are feeling overwhelmed.
Read More
8
Vitamin C triterpene flu inhibitors
Design, synthesis and biological evaluation of novel L-ascorbic acid-conjugated pentacyclic triterpene derivatives as potential influenza virus entry inhibitors.
Relevant investigation of vitamin C
We recently explored the potential of novel compounds that are combinations of L-ascorbic acid, commonly known as vitamin C, and pentacyclic triterpenes in battling the flu. The study focused on compounds we created and tested against the influenza virus in MDCK cells, particularly looking at their effectiveness and any possible side effects.

Among all the compounds we evaluated, one stood out: the 2,3-O,O-dibenzyl-6-deoxy-L-ascorbic acid-betulinic acid conjugate. It displayed significant anti-influenza activity with an effective concentration (EC50) of just 8.7 μM and was not toxic to the cells used in our testing. This suggests that combining vitamin C with these triterpenes might enhance their ability to fight the flu virus, marking an exciting avenue for further research.

We also discovered that this particular compound acts early in the influenza lifecycle, interfering with the virus's ability to attach to cells. We confirmed this by observing that it inhibited the hemagglutination—a crucial step that allows the virus to spread. Our findings indicate that L-ascorbic acid-conjugated triterpenes hold promise as potential anti-influenza agents, specifically targeting viral entry and enhancing the effectiveness of treatment strategies.
Read More
4
Vitamin C shows moderate influenza inhibition
Five Novel Non-Sialic Acid-Like Scaffolds Inhibit In Vitro H1N1 and H5N2 Neuraminidase Activity of Influenza a Virus.
Mixed findings on vitamin C
We investigated the effects of various compounds, including vitamin C, on the neuraminidase (NA) activity of influenza viruses, specifically H1N1 and H5N2. Neuraminidase is crucial for the virus as it helps release new viral particles from infected cells, making it a key target for antiviral treatments.

In this study, we focused on five different compounds that are structurally distinct from sialic acid, which is the natural substrate of neuraminidase. Among those tested, vitamin C was one of the compounds alongside others like acetyl phenylalanylmethionine and propanoic acid derivatives. We found that these compounds inhibited NA activity, but the degree of inhibition varied.

Notably, the inhibition we observed was in the millimolar range, which suggests that while there is some effect, the affinity of vitamin C to inhibit neuraminidase is moderate compared to the reference drug zanamivir. The IC values for the compounds ranged from 6.4 to 73 mM, indicating that they are not as potent as zanamivir.

Overall, our study presents vitamin C and other small organic molecules as potential lead compounds for developing new neuraminidase inhibitors, even if vitamin C’s impact on flu remains to be clarified as part of a broader analysis of multiple compounds.
Read More

Most Useful Reviews

10
Best for influenza
The best remedy for influenza.
Read More
9.5
Quick flu relief
I always keep Ester-C for acute respiratory infections, flu, and colds. This ester form effectively addresses the first symptoms, helping me recover faster. I found it particularly beneficial after childbirth when sleepless nights could be taxing, as it supports tired adrenal glands.
Read More
9.5
Prevents flu complications
Vitamin C is crucial for combating routine colds and flu. A doctor advised me to take it before my surgery, and it worked wonders. I truly noticed its effects when my father was undergoing chemotherapy and radiation, which weakened his immune system. We all caught colds and flu that winter except for him. When I had my heart surgery, I took Vitamin C and didn’t face any illness, even while caring for my grandchildren. Ester C is fantastic as it avoids the burning sensation often associated with other Vitamin C products.
Read More

Medical Researches

SCIENTIFIC SCORE
Possibly Effective
Based on 5 Researches
7.2
  • All Researches
9
Immune booster for flu treatment
Red ginseng and vitamin C increase immune cell activity and decrease lung inflammation induced by influenza A virus/H1N1 infection.
Synergistic effects with limited isolation
We set out to discover how red ginseng and vitamin C work together to enhance immune cell function and fight off viral infections like the flu. In our investigation, we treated human immune cells and specific types of mice unable to produce vitamin C, looking closely at their reaction to influenza A virus/H1N1.

Our findings were quite promising. We observed that both red ginseng and vitamin C elevated the activation levels of immune cells, particularly T-cells and natural killer (NK) cells, known for their vital role in combating viruses. This combination not only helped boost immune cell activity but also reduced lung inflammation caused by the influenza virus, which is crucial for better survival rates during infections.

In cases where vitamin C levels were low in a specific mouse model, we noted that the added nutrients significantly improved their condition. They experienced reduced viral load and inflammation in their lungs after receiving red ginseng and vitamin C, compared to those without this supplementation. These insights suggest that while red ginseng and vitamin C collectively support immune health, the interplay of these substances can be crucial in managing flu infections effectively.
Read More
8
Vitamin C triterpene flu inhibitors
Design, synthesis and biological evaluation of novel L-ascorbic acid-conjugated pentacyclic triterpene derivatives as potential influenza virus entry inhibitors.
Relevant investigation of vitamin C
We recently explored the potential of novel compounds that are combinations of L-ascorbic acid, commonly known as vitamin C, and pentacyclic triterpenes in battling the flu. The study focused on compounds we created and tested against the influenza virus in MDCK cells, particularly looking at their effectiveness and any possible side effects.

Among all the compounds we evaluated, one stood out: the 2,3-O,O-dibenzyl-6-deoxy-L-ascorbic acid-betulinic acid conjugate. It displayed significant anti-influenza activity with an effective concentration (EC50) of just 8.7 μM and was not toxic to the cells used in our testing. This suggests that combining vitamin C with these triterpenes might enhance their ability to fight the flu virus, marking an exciting avenue for further research.

We also discovered that this particular compound acts early in the influenza lifecycle, interfering with the virus's ability to attach to cells. We confirmed this by observing that it inhibited the hemagglutination—a crucial step that allows the virus to spread. Our findings indicate that L-ascorbic acid-conjugated triterpenes hold promise as potential anti-influenza agents, specifically targeting viral entry and enhancing the effectiveness of treatment strategies.
Read More
8
Vitamin C mitigates flu pneumonia
A new mechanism of vitamin C effects on A/FM/1/47(H1N1) virus-induced pneumonia in restraint-stressed mice.
Highly relevant study findings
We examined the effects of vitamin C on pneumonia caused by the influenza virus, specifically the H1N1 strain, in mice under stress. The study found that when exposed to restraint stress, the mice experienced increased mortality and more severe pneumonia symptoms.

However, by giving them oral vitamin C at doses of 125 and 250 mg/kg, we observed a significant reduction in these severe outcomes. Vitamin C seemed to modulate the expression of certain genes related to the immune response, such as MAVS and IRF3, and increased the expression of NF-κB, which plays a key role in the body's antiviral defense.

Our research suggested that vitamin C's protective effects might stem from its ability to inhibit excess cortisol production in the adrenal gland, which is often elevated due to stress. By lowering cortisol levels, vitamin C may help reduce susceptibility to influenza infections, making it a potential ally during the flu season, especially for those experiencing stress.

Through these findings, we highlighted a new mechanism for how vitamin C can be beneficial during influenza infections, particularly for those who are feeling overwhelmed.
Read More
7
Vitamin C's promise against flu
Effect of micronutrient supplements on influenza and other respiratory tract infections among adults: a systematic review and meta-analysis.
Focus on flu; modest benefits
We examined how vitamin C supplementation can impact flu incidence and symptom duration. Our analysis of clinical studies indicated that vitamin C does show promise in reducing the risk of acute respiratory infections, including flu. Specifically, vitamin C reduced the likelihood of catching an acute respiratory infection by approximately 4% (risk ratio of 0.96).

Additionally, we observed that vitamin C also helps shorten the duration of flu symptoms by around 9%. This effect seemed to be more pronounced in men and people from middle-income countries, highlighting the complexity of health factors influenced by gender and socio-economic status.

Overall, while the findings suggest vitamin C can be a modicum of hope in managing flu symptoms, it isn't a standalone solution. Our results advocate for more research to fully understand the impact of vitamin C, especially in the context of the ongoing challenges posed by various respiratory viruses, including influenza.
Read More
4
Vitamin C shows moderate influenza inhibition
Five Novel Non-Sialic Acid-Like Scaffolds Inhibit In Vitro H1N1 and H5N2 Neuraminidase Activity of Influenza a Virus.
Mixed findings on vitamin C
We investigated the effects of various compounds, including vitamin C, on the neuraminidase (NA) activity of influenza viruses, specifically H1N1 and H5N2. Neuraminidase is crucial for the virus as it helps release new viral particles from infected cells, making it a key target for antiviral treatments.

In this study, we focused on five different compounds that are structurally distinct from sialic acid, which is the natural substrate of neuraminidase. Among those tested, vitamin C was one of the compounds alongside others like acetyl phenylalanylmethionine and propanoic acid derivatives. We found that these compounds inhibited NA activity, but the degree of inhibition varied.

Notably, the inhibition we observed was in the millimolar range, which suggests that while there is some effect, the affinity of vitamin C to inhibit neuraminidase is moderate compared to the reference drug zanamivir. The IC values for the compounds ranged from 6.4 to 73 mM, indicating that they are not as potent as zanamivir.

Overall, our study presents vitamin C and other small organic molecules as potential lead compounds for developing new neuraminidase inhibitors, even if vitamin C’s impact on flu remains to be clarified as part of a broader analysis of multiple compounds.
Read More

User Reviews

USERS' SCORE
Good
Based on 17 Reviews
8.8
  • All Reviews
  • Positive Reviews
  • Negative Reviews
10
Best for influenza
The best remedy for influenza.
9.5
Quick flu relief
I always keep Ester-C for acute respiratory infections, flu, and colds. This ester form effectively addresses the first symptoms, helping me recover faster. I found it particularly beneficial after childbirth when sleepless nights could be taxing, as it supports tired adrenal glands.
9.5
Prevents flu complications
Vitamin C is crucial for combating routine colds and flu. A doctor advised me to take it before my surgery, and it worked wonders. I truly noticed its effects when my father was undergoing chemotherapy and radiation, which weakened his immune system. We all caught colds and flu that winter except for him. When I had my heart surgery, I took Vitamin C and didn’t face any illness, even while caring for my grandchildren. Ester C is fantastic as it avoids the burning sensation often associated with other Vitamin C products.
Read More
9.5
Effective against flu
This one is exceptional! With everyone coughing and sneezing this flu season, I'm strengthening my immune health with this 1000mg Ester-C. It is notably effective and works quickly, making me a repeat buyer.
9.5
Effective composition
We use this for colds and flu! The drug has an excellent composition and is effective. Unlike other vitamin C forms, it does not adversely affect the gastric mucosa. The capsules might be large, but that's a minor issue!

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