Vitamin C
Vitamin C (ascorbic acid) is a water-soluble essential nutrient that humans cannot produce internally due to a genetic mutation shared by all primates. Found abundantly in citrus fruits, bell peppers, and cruciferous vegetables, it serves as one of the body's primary antioxidants and is required for collagen synthesis, neurotransmitter production, and proper immune cell function.
Expert Evidence
16 references from 3 experts
“During times of exposure to viral illness, I also supplement with liposomal vitamin C by Pure Encapsulations.”
This Is Everything Rhonda Patrick Supplements With
1:448 references in 4 episodes from 2014–2025
Rhonda Patrick takes vitamin C personally and views it favorably for reducing inflammation, supporting cardiovascular health, and improving fertility markers. She provides practical guidance on oral dosing limits and bioavailability, and cautions those with high iron levels against supplementation. She has not discussed stopping or reconsidering her use.
Consumption
She takes vitamin C in the evening after dinner and supplements with liposomal vitamin C from Pure Encapsulations during times of viral illness exposure.
Benefits
She highlights vitamin C's ability to reduce C-reactive protein in those with elevated baseline levels, reduce atherosclerotic lesions alongside vitamin E, and significantly improve sperm count and motility in infertile men.
Best Practices
She notes that oral vitamin C peaks at 220 micromoles per liter in plasma regardless of dose, while intravenous administration can reach far higher concentrations. The tolerable upper intake is 2,000 mg per day due to potential GI issues, though most people tolerate higher doses well.
Cautions
She warns that people with hemochromatosis or abnormally high iron levels should be cautious with vitamin C supplementation because it enhances dietary iron absorption.
“We know that our cells have got all of the vitamin C that they need at daily intakes of only 100 milligrams. When higher doses are tested in humans, there's no benefits seen, no improvement on cardiovascular disease, cancer, or death rates.”
Longevity Influencers Are Making You Sick
10:457 references in 4 episodes from 2021–2023
Brad Stanfield recommends against vitamin C supplementation, arguing that cells are fully saturated at just 100mg daily — easily obtained from diet — and that higher doses show no benefits for cardiovascular disease, cancer, or mortality. There is no evidence of personal use. He does note vitamin C's role in enhancing iron absorption when prescribed alongside iron supplements.
Benefits
Clinical trials suggest vitamin C supplementation alone offers no benefit in cancer prevention.
Best Practices
Cells are fully saturated at 100mg daily, achievable through five servings of fruits and vegetables; supplements on top of a good diet are poorly absorbed. He prescribes 100mg vitamin C alongside iron supplements to improve iron absorption.
Cautions
No benefits seen at higher doses for cardiovascular disease, cancer, or death rates. Common side effects include diarrhea, nausea, and abdominal cramps, with a theoretical increased risk of kidney stones.
“...50 milligrams is the general dosage for the activation. The collagen needs to be actually absorbed and utilized and vitamin C is an important co-actor in that process.”
Dr. Michael Ormsbee: Food Timing, Nutrition & Supplements for Fat Loss, Muscle Growth & Recovery
1:34:151 reference in 1 episode
Galpin recommends 50 mg of vitamin C as a co-factor to activate collagen absorption and utilization. No evidence of personal use, no cautions discussed, and no guidance beyond its role in collagen metabolism.
Side Effects
- Diarrhea or loose stools at high doses
- Nausea or stomach cramps
- Increased oxalate excretion (relevant for kidney stone risk)
- Possible interference with certain lab tests
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