Most adults need 75 to 90 mg of vitamin C per day, an amount you can get from a single cup of broccoli or a medium orange. That’s the recommended dietary allowance set by the National Institutes of Health: 90 mg for men and 75 mg for women aged 19 and older. But the amount that’s right for you depends on your age, whether you smoke, and what you’re trying to get out of it.
Recommended Daily Amounts by Age
Vitamin C needs change significantly throughout life. Babies up to 6 months old need about 40 mg daily (easily covered by breast milk or formula), rising to 50 mg between 7 and 12 months. For toddlers aged 1 to 3, the recommendation drops to just 15 mg, then climbs steadily: 25 mg for children 4 to 8, and 45 mg for ages 9 to 13.
Adults 19 and older settle at 90 mg for men and 75 mg for women, and those numbers stay constant through old age. If you’re pregnant, the recommendation increases to 85 mg; if breastfeeding, 120 mg. Smokers need an extra 35 mg per day on top of the standard recommendation because smoking depletes vitamin C faster, putting the target at roughly 125 mg for men and 110 mg for women who smoke.
Foods That Cover Your Daily Needs
A cup of sliced kiwifruit delivers about 167 mg of vitamin C, nearly double the daily target for most adults. A cup of raw orange sections provides around 87 mg. A cup of frozen broccoli has 88 mg raw, though cooking drops that to about 74 mg. Even a single medium orange with the peel provides over 120 mg.
The takeaway: if you eat a few servings of fruits and vegetables each day, you’re almost certainly hitting your vitamin C needs without a supplement. Cooking reduces vitamin C content because it breaks down in heat and dissolves in water, so raw or lightly steamed produce retains more.
Your Body Stops Absorbing After a Certain Dose
Here’s something most people don’t realize: your intestines can only absorb so much vitamin C at once. At a dose of 200 mg, absorption is essentially complete, meaning your body takes in nearly all of it. Once you go above 500 mg in a single dose, absorption drops significantly, and the excess is simply excreted through urine.
This means that taking a 1,000 mg supplement doesn’t give you five times the benefit of a 200 mg dose. Your body uses what it can and flushes the rest. If you do want to supplement above 200 mg, splitting the dose across the day (say, 250 mg twice) will get more into your bloodstream than taking it all at once.
Does Extra Vitamin C Help With Colds?
The short answer: it won’t prevent a cold, but it can make one shorter and less miserable if you’re already taking it regularly. A meta-analysis of trials using 1 gram (1,000 mg) or more per day found that regular supplementation reduced the severity of colds by about 15% and shortened the time people were stuck at home or out of school by a similar margin. For the most severe symptoms, the reduction was larger, around 26%.
Two trials that focused on people under heavy physical stress in cold environments found an even bigger effect: roughly 60% shorter duration of severe symptoms, though those results came from small studies. The key detail is that vitamin C only helped when people were already taking it before they got sick. Starting a supplement after symptoms appear doesn’t seem to do much.
The Upper Limit and Side Effects
The tolerable upper intake level for adults is 2,000 mg per day. Going above that regularly increases the risk of digestive problems, particularly diarrhea, nausea, and stomach cramps. Vitamin C is water-soluble, so your body doesn’t store large amounts, but consistently high doses can still cause trouble.
The more serious concern is kidney stones. A large study following men over time found that the risk of developing a first kidney stone became statistically significant at total vitamin C intakes of 700 to 800 mg per day. At 1,000 mg or more daily, the risk of a first stone increased by 41% compared to intakes of 90 mg or less. This risk appears more pronounced in men and in people with a history of kidney stones, so mega-dosing isn’t without real consequences.
Liposomal vs. Standard Supplements
If you’ve browsed the supplement aisle, you’ve probably seen liposomal vitamin C marketed as better absorbed. Clinical testing supports this to a degree: liposomal formulations (where vitamin C is wrapped in tiny fat particles) are roughly 1.8 times more bioavailable than standard ascorbic acid tablets. That means more of the vitamin reaches your bloodstream per dose.
Whether that matters depends on how much you’re taking. At doses under 200 mg, regular ascorbic acid is already absorbed almost completely, so the liposomal version offers little advantage. The difference becomes more meaningful at higher doses where standard absorption drops off. Liposomal supplements also cost significantly more, so for most people eating a reasonable diet, they’re an unnecessary upgrade.
A Practical Target
For general health, 75 to 90 mg from food handles the job. If you want the immune benefits seen in cold studies, 200 mg daily is the sweet spot where absorption is still complete and you’re well above the minimum. Going to 1,000 mg may offer modest additional cold relief but comes with diminishing returns on absorption and a meaningful increase in kidney stone risk for some people. Staying under 2,000 mg keeps you within the established safety margin.