High Quality Vitamin C Supplements

RDA is 75–90 mg/day, but most supplements provide 500–1,000 mg. Higher doses (1–2 g/day) saturate plasma. Liposomal vitamin C reaches higher blood levels with less GI upset. Acute illness doses go up to 3–4 g/day in divided doses.

It doesn't prevent colds in the general population, but daily supplementation reduces cold duration by about 8% in adults and 14% in children. Higher acute doses at the first sign of symptoms may also shorten illness.

Ascorbic acid is fine for most people. Buffered forms (calcium ascorbate, magnesium ascorbate) are gentler on the stomach. Liposomal vitamin C reaches the highest blood levels. Avoid mega-dosing without need — excess is excreted.

Food sources (citrus, bell peppers, kiwi, strawberries, broccoli, cantaloupe) come with bioflavonoids and other nutrients that enhance absorption. For RDA-level needs, food is plenty. For higher therapeutic doses (1,000+ mg), supplements are practical.

Yes, if you're iron-deficient — vitamin C significantly boosts non-heme iron absorption (especially from plant sources). Take 200–500 mg vitamin C with iron supplements or iron-rich plant foods. People with iron overload conditions should avoid this combination.

In susceptible people (especially men with a history of calcium oxalate stones), high-dose vitamin C (above 1,000 mg/day) may slightly increase stone risk because it converts to oxalate. Stay below 500–1,000 mg if you have a stone history.

Liposomal vitamin C is encapsulated in phospholipids, which protects it during digestion and improves absorption. It reaches higher blood levels with smaller doses and less GI upset. It's pricier — worth it for therapeutic doses, less necessary for daily maintenance.

Up to 2,000 mg/day is the upper limit. Doses above this can cause GI upset, diarrhea, and theoretically kidney stones in susceptible people. IV vitamin C bypasses these limits but should only be done in clinical settings.

Anytime, but with food if it causes stomach upset. Vitamin C has a 30-minute absorption window, so divided doses (250–500 mg twice daily) are better than one large dose. Take separately from copper or vitamin B12 absorption isn't significantly affected.