Vitamin C IV is one of the most-requested additives on our menu and one of the most over-claimed ingredients in the industry. The pharmacology is genuinely interesting; the marketing runs well ahead of it.
Why IV changes the math
Oral vitamin C absorption is saturable. Intestinal transporters cap uptake, so plasma concentration plateaus in the low micromolar range no matter how much you take — and the excess is excreted. Intravenous administration bypasses the gut and can produce plasma levels one to two orders of magnitude higher. This is well-documented pharmacokinetics, not a marketing claim.
The open question is which outcomes actually depend on those levels.
Immune claims, graded
Vitamin C supports neutrophil function and is consumed rapidly during acute infection, and plasma levels genuinely fall when you are sick. Supplementation data in healthy adults shows modest effects on cold duration rather than prevention, and most of that literature studies oral dosing. Reasonable to use during illness or a demanding travel and event season; unreasonable to promise it will keep you from getting sick. Our immune formulations are on the immune support page.
Skin and collagen claims, graded
Vitamin C is a required cofactor for collagen synthesis — that part is textbook biochemistry. Whether supraphysiologic infusion improves skin appearance beyond correcting a deficiency has not been convincingly shown. Paired with glutathione it is a popular aesthetic protocol; see the glutathione evidence for the same honest treatment.
High dose and the mandatory G6PD test
This is the safety point that matters. In people with G6PD deficiency, high-dose IV vitamin C can trigger acute hemolysis — red blood cell destruction. It is an inherited enzyme deficiency, more common in men and in people of Mediterranean, African, and Southeast Asian ancestry, and most carriers have no idea.