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Our read is that taking vitamin C is well supported for various health benefits, though optimal dosing and long-term effects remain areas of active discussion.
Our read is that vitamin C offers several benefits, including protection against oxidative damage, support for immune function, and potential improvements in skin health and gingivitis risk. Experts like Rhonda Patrick and Paul Saladino highlight its role in cellular protection and the regeneration of glutathione.
However, there are significant caveats regarding optimal dosage, with some experts like Paul Saladino and Rhonda Patrick suggesting that intakes above 30-70mg per day may not provide additional benefits and could even be dangerous due to oxalate conversion and potential for kidney stones.
While high-dose intravenous vitamin C is used in cancer protocols, and oral intakes above the RDA are generally well-tolerated, the ideal daily intake for humans is not well-established, and megadosing may block beneficial signaling pathways.
Paul Saladino takes two to three scoops of beef collagen with electrolytes, vitamin C, and elderberry every morning before coffee. Bryan Johnson's current skincare routine includes peptide cream, vitamin C, vitamin E, folic acid, tretinoin, and laser treatments. A 'sperm enhancement protocol' for male patients with abnormal sperm parameters involves 1 gram of L-carnitine with 1 gram of vitamin C, taken alongside a multivitamin and CoQ10, according to Andrew Huberman. Rhonda Patrick suggests taking vitamin C at night may allow for normal levels by morning workouts, assuming plasma levels return to baseline within 3 hours.
Vitamin C has no proven benefits in humans other than preventing scurvy, according to Paul Saladino. Obtaining vitamin C from low-oxalate fruits is suggested (Paul Saladino). Megadosing vitamin C and vitamin E may block beneficial signaling pathways (Paul Saladino). Vitamin C intake above 30-70mg per day may not provide benefits for humans and higher doses might be dangerous due to conversion to oxalate (Rhonda Patrick, Paul Saladino). Antioxidant supplements like vitamin C and vitamin E have failed to prevent cardiovascular disease or improve mortality and have sometimes been associated with higher mortality (Paul Saladino). Vitamin C intake above 30-70 mg per day may not be optimal for humans and could potentially be dangerous (Paul Saladino). Low vitamin C intake and deficiencies impair biological processes, increasing the risk for decreased fat utilization during exercise and increased severity of Alzheimer's disease (Rhonda Patrick). Pharmacologic doses of intravenous vitamin C (greater than 1 gram) can generate hydrogen peroxide, which can damage DNA, RNA, and proteins (Rhonda Patrick). Vitamin C supplementation to supranormal levels has not been conclusively shown to protect against cataract formation (Peter Attia). Consistently taking synthetic Vitamin C supplements is associated with a two times higher risk of developing kidney stones (Rhonda Patrick, Paul Saladino). Combinations of vitamin C and vitamin E may blunt hypertrophic adaptations (Andrew Huberman). Consumption of synthetic vitamin C has been associated with worsening cardiovascular disease metrics in observational studies (Paul Saladino). Mega-doses of vitamin C supplements or consuming large quantities of oranges can potentially create problems (Paul Saladino). Increasing vitamin C consumption from 70mg to 250mg daily through fruit and vegetables does not improve antioxidant capacity (Paul Saladino). Gastric acid limits the absorption of oral vitamin C beyond a certain level in the gut (Peter Attia). Antioxidants are generally not harmful unless taken in mega-doses, and small amounts are necessary for immune function and mitochondrial health (mitohormesis) (Andrew Huberman). Vitamin E, superoxide dismutase, glutathione, and uric acid may be the primary antioxidants in humans, not vitamin C (Paul Saladino). Intravenous vitamin C has been used to treat viral infections like shingles and mononucleosis, though clinical studies are lacking for herpes (Rhonda Patrick). Humans lost the ability to synthesize vitamin C approximately 40-60 million years ago (Paul Saladino). The recommended dietary allowance for vitamin C is 60 mg for women and 80-90 mg for men (Paul Saladino). The Inuit historically consumed an estimated 38 mg of vitamin C per day, primarily from animal foods (Paul Saladino). Low vitamin C levels in patients with sepsis may predict increased risk for organ failure (Rhonda Patrick, Paul Saladino). Supplementing with vitamin C showed a statistically significant increase in kidney stone risk, but the clinical significance is negligible (Rhonda Patrick). Supplemental vitamin C doses of 1-2 grams per day for 1-2 weeks did not improve immune function before or after prolonged exercise in most studies, but results were more promising in high-endurance athletes when vitamin C was combined with other antioxidants (Rhonda Patrick). People with the highest baseline vitamin C levels also had lower risk factors for respiratory diseases (Rhonda Patrick). Steady-state plasma vitamin C concentrations from consuming 5-9 servings of vitamin C-rich fruits and vegetables daily are around 80 micromoles per liter or less (Rhonda Patrick). Molecular hydrogen does not donate electrons and remain stable like polyphenols or vitamin C due to its reaction kinetics (Paul Saladino).
Few, if any, steak-dominant carnivores achieve 50 micromolar/liter plasma vitamin C without organ meats (Paul Saladino). Vitamin C intakes above the amount needed to prevent scurvy may not provide additional antioxidant benefits in non-diabetic, non-insulin-resistant individuals (Paul Saladino). More randomized placebo-controlled studies are needed to determine if vitamin C improves asthma symptoms and severity, and if outcomes are affected by dose, age, or baseline vitamin C levels (Rhonda Patrick). More randomized placebo-controlled studies are needed to determine the effectiveness and duration of effects of intravenous vitamin C in reducing blood pressure (Rhonda Patrick). It is unclear whether vitamin C alone, separate from vitamin E, would blunt exercise-induced insulin sensitivity, as studies often include both antioxidants (Rhonda Patrick). Vitamin C may increase the incidence of pneumonia in individuals with very low plasma levels of vitamin C (Rhonda Patrick). The necessity of 50 micromolar/liter plasma fasting vitamin C for preventing heart disease, potentially mediated by LDL oxidation, is debatable (Paul Saladino). The ideal daily intake of vitamin C for humans is not well-established, and large doses may be damaging (Paul Saladino). There is limited research on the optimal timing of vitamin C supplementation for exercise adaptations (Rhonda Patrick).
Benefits hold across the populations where it's been tested.
The effect size is large enough to matter clinically, not just statistically.
The intervention improves the primary outcome at standard doses in healthy adults.
Benefits hold across the populations where it's been tested.
The intervention improves the primary outcome at standard doses in healthy adults.
Animal-model results don't translate to the human protocol being recommended.
Most of the support comes from short or small studies.
The headline effect shrinks once you account for trial quality.
Most of the support comes from short or small studies.
The headline effect shrinks once you account for trial quality.