Vitamin C is largely ignored by the medical community. High dose vitamin C is considered even outrageous.
"High dose" is really a misnomer. A better term would be "adequate dose."
Why would it be that a size convenient for swallowing has to be the right amount? In some respect, the more of something that is required, the potentially more important it is because of this "great" need. Vitamin C, in my experience, works best to prevent the duration of viruses (the common cold is comprised of many viruses from different families).
4 grams (capsules, pills) - 3 times/day.
Daily, without any symptoms, the right amount is probably 1-3 grams. I, personally, don't take vitamin C daily because of a high consumption of foods high in vitamin C. But when I feel something "coming on," I go right to the high dose.
Here is some vitamin C research, published in mainstream medical journal, assembled by another medical scientist.
Sepsis is a potentially life-threatening condition caused by the body’s innate immune response to acute infection. Under some circumstances, aspects of this response that are typically associated with defense against infection can induce extensive cell and tissue damage, leading to multiple organ failure, the hallmark of sepsis. Acute respiratory distress syndrome (ARDS) is a common sepsis-associated organ injury that can lead to respiratory failure and death. A 2019 phase 2 trial found that intravenous vitamin C reduced death rates among patients with sepsis and ARDS.
The randomized, double-blind, placebo-controlled, multicenter trial took place in seven medical intensive care units in the United States over a period of three years. The study participants included 167 male and female patients (average age, 55 years) with sepsis and ARDS. Every six hours for four days, the patients received either intravenous vitamin C (50 milligrams per kilogram of body weight) or a placebo.
The authors of the study noted a substantial difference in the death rates among the two groups. Whereas approximately 30 percent of patients who received intravenous vitamin C died, more than 46 percent of patients who received the placebo died. Patients who received vitamin C also had fewer ventilated days, spent less time in intensive care (seven days versus ten), and their hospital stays were approximately one week shorter than those who received the placebo.
These findings suggest that intravenous vitamin C administration might be beneficial in critically ill patients who have sepsis and respiratory failure.
The bulk of scientific research on the effectiveness of vitamin C in fighting infection has centered on reducing the symptoms and duration of the common cold, with mixed results. Most of these studies have used doses of approximately 1 gram per day, however. Findings from a 2017 study suggest that much larger doses might be more effective at reducing a cold’s duration.
Although most adults typically have only one or two colds per year, cold symptoms are the reason for many lost days of work or school. Some evidence suggests that the financial costs associated with having a cold are similar to those associated with having high blood pressure or a stroke.
The author of the study reviewed the findings of two randomized trials focused on the effectiveness of vitamin C in reducing cold symptom duration. One of the trials had four treatment groups: one group that took a placebo, two groups that took 3 grams per day, and one group that took 6 grams per day. The 6-gram dose reduced cold symptom duration by about 17 percent – roughly twice as much as that observed with only 3 grams. The placebo had no effect on symptom duration. The other trial had three treatment groups: one that took 4 grams per day, one that took 8 grams per day, and one that took a placebo. Taking 8 grams per day reduced symptom duration by 21 percent, compared to the placebo group.
These findings suggest that large doses of oral vitamin C might reduce the duration of symptoms associated with the common cold, but self-dosing should commence as soon as cold symptoms appear for the greatest benefit.
Mechanical ventilation – a therapeutic measure used to assist or replace spontaneous breathing – is an important strategy used to treat people experiencing respiratory failure. A recent meta-analysis found that vitamin C treatment shortened the duration of mechanical ventilation among patients in intensive care.
The investigators looked at the findings from eight trials involving 685 patients. They found that vitamin C shortened the duration of mechanical ventilation an average of 14 percent. But the investigators noted major differences in the effect of vitamin C between the trials, with the greatest benefit, observed among patients who were on mechanical ventilation for the longest duration – the patients who were most critical. In five trials involving more than 470 patients requiring ventilation for more than 10 hours, providing 1 to 6 grams of vitamin C per day shortened ventilation time an average of 25 percent.
These findings indicate that vitamin C shortens the duration of mechanical ventilation, especially among critically ill patients.
Inflammation is a biological phenomenon triggered by the immune system in response to a physical injury or infection. Vitamin C’s immune-boosting and antioxidant properties can mediate the body’s inflammatory response, reducing the symptoms or risk of various diseases. Evidence suggests that vitamin C can lower C-reactive protein (CRP), a marker of inflammation.
C-reactive protein is a protein that increases in the blood with inflammation and infection as well as following a heart attack, surgery, or trauma. It is one of several proteins that are often referred to as acute phase reactants. Blood levels of CRP greater than 1 milligram per liter are indicative of elevated cardiovascular disease risk.
The randomized study involved nearly 400 healthy adults (average age, 44 years) who took 1 gram of vitamin C, 800 international units of vitamin E, or a placebo every day for two months. The findings revealed that vitamin E had no effect on lowering CRP; however, vitamin C supplementation decreased CRP 16.7 percent compared to pre-treatment measurements, but only in participants who had baseline CRP levels above 1 milligram per liter. This reduction in CRP was comparable to those achieved with statins (cholesterol-lowering drugs).
Interestingly, the study identified a strong link between obesity and elevated CRP levels. Whereas 25 percent of normal-weight people had elevated CRP levels of CRP, 50 percent of overweight participants and 75 percent of obese participants had elevated levels.
These findings suggest that vitamin C might decrease inflammation to a similar magnitude as some statins in people at a higher risk of cardiovascular disease based on CRP levels.
Catechins are bioactive compounds present in green tea. Some catechins, such as epigallocatechin gallate (EGCG), are potent scavengers of reactive oxygen species with demonstrated antioxidant, anti-inflammatory, and anticarcinogenic properties in both clinical and in vitro studies. Evidence suggests that vitamin C might increase the bioavailability of the catechins present in green tea.
Consumers of green tea commonly add milk, lemon, or other substances to their tea. To assess the impact that these additives have on catechin bioavailability, the authors of the study added varying quantities of citric acid, BHT and EDTA (common preservatives), ascorbic acid (vitamin C), milk (cow’s, soy, and rice), and citrus juice (orange, grapefruit, lemon, or lime) to prepared tea. Then they subjected the tea formulations to simulated digestive processes and measured the amount of catechins they recovered.
They found that overall, green tea catechin recovery was poor, with more than 80 percent loss of catechins during digestion. Adding milk to tea increased catechin recovery considerably, but the greatest improvements were observed with the addition of vitamin C or citrus juices, the latter of which increased recovery to 98 percent.
Citrus juices contain bioactive compounds that might influence catechin recovery, but they are also rich in vitamin C. These findings suggest that consumption of green tea with vitamin C, especially in conjunction with other bioactive compounds in citrus juices, increases the recovery of the beneficial components present in the tea.
Exercise-induced bronchoconstriction – a narrowing of the airways in response to exercise – occurs in up to 10 percent of the general population and up to 50 percent of some competitive athletes. Findings from a meta-analysis suggest that vitamin C might reduce the incidence of exercise-induced bronchoconstriction.
Previous research demonstrated that vitamin C can triple respiratory tissue levels within an hour or two of a single oral dose of 1 or 2 grams. This local increase in vitamin C concentration appears to protect against acute increases in airway oxidative stress. In addition, vitamin C inhibits the production of prostaglandins and leukotrienes, biological compounds that participate in the pathogenesis of exercise-induced bronchoconstriction. In addition, vitamin C halved the incidence of the common cold among people experiencing heavy short-term physical stress – an indication that vitamin C might also have other effects on people experiencing heavy physical exertion.
The authors of the current study conducted analyses of nine studies that investigated varied aspects of the effects of vitamin C on exercise-induced bronchoconstriction. Three placebo-controlled studies analyzed the relative exercise-induced decline in forced expiratory volume, or FEV1, (a measure of respiratory capacity) with or without vitamin C. These trials found that doses ranging between 0.5 and 2 grams of vitamin C reduced FEV1 decline by half. Similarly, five studies investigated the effects of vitamin C supplementation on respiratory symptoms after short-term heavy physical work and found that incidence was halved. One study investigated the duration of respiratory symptoms in young male swimmers and also found that incidence was halved.
The authors noted that a variety of factors might influence whether and to what degree vitamin C affects respiratory function during exercise, including the type of activity and the conditions under which it is performed, among others.
The human body responds to mental stress by releasing hormones called corticosteroids, triggering the body’s fight or flight response. Chronic activation of these hormones can impair immune function, increasing susceptibility to infection and disease. Findings from an early study in mice demonstrate that vitamin C mitigates the body’s stress response, thereby improving immunity.
The authors of the study immobilized mice for an hour every day for three weeks to induce stress. They also fed the mice 200 milligrams of vitamin C daily – roughly equivalent to several grams per day in humans. A control group of mice also received vitamin C but they were not subjected to stress.
The stressed mice that received large doses of vitamin C in their diets exhibited fewer signs of stress as evidenced by lower levels of corticosteroid hormones as well as other physical manifestations, such as weight loss. The mice also exhibited higher levels of IgG, the most abundant antibody in circulation, responsible for binding a broad selection of pathogens such as viruses, bacteria, and fungi, to prevent infection. Interestingly, the non-stressed mice that received large doses of vitamin C exhibited even greater increases in IgG, suggesting that stress cancels out some of the beneficial effects of the vitamin.
These findings suggest that high dose vitamin C might improve immune function, especially during times of mental and physical stress.