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Check vitamin C intake vs RDA by age and sex — see mg/day, % of RDA and food sources.
Check vitamin C intake vs RDA by age and sex — see mg/day, % of RDA and food sources.
Enter values above and click Calculate — results will appear here with the formula explained.
Vitamin C RDA is 90 mg daily for men and 75 mg for women 19+ (plus 35 mg for smokers) — covering antioxidant defense, collagen synthesis, iron absorption and immune function with margin above scurvy prevention (~10 mg). This calculator checks intake as percent of RDA; one orange (~70 mg) or bell pepper (~80 mg) nearly covers it alone.
Source density favors fresh produce: bell peppers, kiwi, citrus, strawberries, broccoli and potatoes all deliver 50–100 mg per serving. Five daily fruit-vegetable servings virtually guarantee adequacy — deficiency in developed countries appears almost exclusively with zero produce intake (food deserts, extreme restriction, alcoholism), presenting as fatigue, gum bleeding and poor wound healing.
Smokers need +35 mg because each cigarette oxidizes roughly 25–50 mg of ascorbate; passive smoke, pollution and chronic inflammation raise turnover similarly. Vapers, foundry workers and the chronically ill sit in the same higher-need boat — the RDA's smoker bump acknowledges chemistry, not moral judgment.
Megadose reality check: plasma saturates near 200 mg daily intake (~70–80 µM); beyond ~500–1,000 mg, absorption drops and urinary excretion soars — expensive urine with occasional diarrhea and kidney-stone risk in susceptible men. No trial shows cold prevention in the general population (Cochrane: ~8% shorter colds in adults, meaningful only for marathoners and soldiers).
Cooking destroys it progressively: boiling leaches 30–50% into water (use the liquid), steaming halves losses, microwaving preserves most, and raw storage degrades slowly over days. Eat a mix of raw and lightly cooked produce rather than chasing numbers with pills.
Iron synergy is C's underrated job: 25–100 mg with plant meals doubles non-heme iron absorption — vegetarians pairing lentils with bell peppers or citrus solve two nutrients at once. This interaction matters more for public health than any megadose protocol.
Check vitamin C intake vs RDA by age and sex — see mg/day, % of RDA and food sources. Formula: RDA: M 90mg, F 75mg (19+). Example: At 30 male, 80 mg intake: 89% of the 90 mg RDA — half an orange (~35 mg) closes it.
Vitamin C RDA is 90 mg daily for men and 75 mg for women 19+ (plus 35 mg for smokers) — covering antioxidant defense, collagen synthesis, iron absorption and immune function with margin above scurvy prevention (~10 mg). This calculator checks intake as percent of RDA; one orange (~70 mg) or bell pepper (~80 mg) nearly covers it alone.
Source density favors fresh produce: bell peppers, kiwi, citrus, strawberries, broccoli and potatoes all deliver 50–100 mg per serving. Five daily fruit-vegetable servings virtually guarantee adequacy — deficiency in developed countries appears almost exclusively with zero produce intake (food deserts, extreme restriction, alcoholism), presenting as fatigue, gum bleeding and poor wound healing.
Smokers need +35 mg because each cigarette oxidizes roughly 25–50 mg of ascorbate; passive smoke, pollution and chronic inflammation raise turnover similarly. Vapers, foundry workers and the chronically ill sit in the same higher-need boat — the RDA's smoker bump acknowledges chemistry, not moral judgment.
Megadose reality check: plasma saturates near 200 mg daily intake (~70–80 µM); beyond ~500–1,000 mg, absorption drops and urinary excretion soars — expensive urine with occasional diarrhea and kidney-stone risk in susceptible men. No trial shows cold prevention in the general population (Cochrane: ~8% shorter colds in adults, meaningful only for marathoners and soldiers).
Cooking destroys it progressively: boiling leaches 30–50% into water (use the liquid), steaming halves losses, microwaving preserves most, and raw storage degrades slowly over days. Eat a mix of raw and lightly cooked produce rather than chasing numbers with pills.
Iron synergy is C's underrated job: 25–100 mg with plant meals doubles non-heme iron absorption — vegetarians pairing lentils with bell peppers or citrus solve two nutrients at once. This interaction matters more for public health than any megadose protocol.
At 30 male, 80 mg intake: 89% of the 90 mg RDA — half an orange (~35 mg) closes it. A smoker needs 125 mg; the same 80 mg covers only 64%, requiring a full bell pepper on top.
Last reviewed: September 2026 · Report an error