What vitamin C does and why your body needs it
Vitamin C is a nutrient your body uses to build and repair tissue, fight off infections, and protect your cells from damage. Unlike some vitamins, your body cannot store it — you need a fresh supply from food or supplements every day. When you get enough vitamin C, your immune system works better, your wounds heal faster, and your skin stays healthier.
Your body also uses vitamin C to make collagen, a protein that holds your skin, bones, and connective tissue together. Without enough of it, small cuts take longer to heal, your gums can bleed more easily, and your joints may feel weaker. Most people get vitamin C from citrus fruits, berries, peppers, and leafy greens, but some people take supplements to make sure they have enough.
Key Takeaways
- Vitamin C helps your immune system fight infection, heals wounds faster, and protects your cells from damage caused by free radicals.
- Your body does not store vitamin C, so you need to get it from food or supplements regularly throughout the week.
- Most adults need 75 to 90 milligrams per day, though the amount varies based on age, sex, and whether you smoke.
- Too much vitamin C from supplements can cause stomach upset and kidney stones in people with certain health conditions.
- Food sources like oranges, strawberries, and bell peppers deliver vitamin C along with fiber and other nutrients supplements do not contain.
How much vitamin C you actually need
The amount of vitamin C your body needs depends on your age and sex. Adult women need 75 milligrams per day, and adult men need 90 milligrams per day. If you smoke, you need an extra 35 milligrams on top of that, because smoking uses up vitamin C faster in your body.
One medium orange has about 70 milligrams of vitamin C, and one cup of strawberries has about 85 milligrams. A single red bell pepper has around 150 milligrams. This means most people who eat a normal diet with some fruits and vegetables get enough without thinking about it. You do not need a supplement unless your diet is very limited or your doctor tells you that you do.
What happens when you do not get enough
If you go weeks without vitamin C, your body starts to struggle. Your immune system weakens, so you catch colds more easily. Wounds and cuts take much longer to heal. Your gums may swell or bleed when you brush your teeth. In extreme cases — which are rare in developed countries — a severe shortage causes scurvy, a condition where old wounds reopen and your body breaks down.
People most at risk for low vitamin C are those who eat very few fruits and vegetables, smoke heavily, or have certain digestive conditions that make it hard to absorb nutrients. If you fall into one of these groups, talking to your doctor about whether you need a supplement makes sense.
Food sources versus supplements
Getting vitamin C from food is usually better than taking a pill, because food delivers other nutrients at the same time. An orange gives you vitamin C plus fiber, potassium, and folate. A bell pepper gives you vitamin C plus vitamin A and antioxidants. A supplement gives you only the vitamin C.
Supplements can be useful if you cannot eat enough fruits and vegetables, or if your doctor thinks you need extra. But taking more than 2,000 milligrams per day from supplements can cause stomach pain, diarrhea, and nausea. In people with a history of kidney stones or certain blood disorders, too much vitamin C can be risky. Food sources do not carry this risk because you cannot eat enough to overdose.
Who might need a vitamin C supplement
Most people do not need a supplement if they eat a varied diet. But some groups may benefit from one. People who smoke, people with very limited diets, people recovering from surgery or serious illness, and people with certain digestive disorders may not get enough from food alone.
If you are thinking about taking a supplement, talk to your doctor first. They can tell you whether you actually need one, what dose is safe for you, and whether it might interact with any medicines you take. Some supplements can interfere with blood thinners, diabetes medicines, and other drugs.
Signs you might not be getting enough vitamin C
Early signs of low vitamin C include feeling tired more often than usual, getting sick more frequently, and noticing that small cuts or scrapes take longer to heal than they used to. Your gums might bleed a little when you floss, or you might bruise more easily. These signs do not always mean you have a vitamin C shortage — they can come from many things — but they are worth paying attention to.
If you notice these patterns, the first step is usually to eat more fruits and vegetables rather than jump to a supplement. Add an orange to breakfast, snack on strawberries, or roast some bell peppers with dinner. If the signs do not improve after a few weeks, or if you cannot eat enough produce because of cost or access, talk to your doctor about whether a supplement makes sense for you.
How your body uses vitamin C throughout the day
When you eat or take vitamin C, your small intestine absorbs most of it into your bloodstream within a few hours. Your body then sends it to cells that need it most — your immune cells, your skin, your bones, and your connective tissue. Any extra vitamin C that your body does not use is filtered out by your kidneys and lost in urine, which is why you cannot build up a reserve.
This is why eating vitamin C regularly matters more than eating a huge amount once a week. Your body works better when you have a steady supply. If you take a supplement, spreading it across the day — rather than taking one large dose — helps your body absorb and use more of it.
Frequently Asked Questions
Can you get too much vitamin C from eating fruit?
No. You would have to eat an unrealistic amount of fruit to overdose on vitamin C from food alone. Supplements are where overdose becomes possible, because a single pill can contain several times what you need in a day.
Does vitamin C prevent colds?
Regular vitamin C does not prevent colds in most people. However, in people under extreme physical stress — like athletes in intense training — it may shorten how long a cold lasts by a day or two. For most people, it does not make a difference.
Is it better to take vitamin C in the morning or evening?
The time of day does not matter much. What matters is that you get it regularly. If you take a supplement, spreading it across meals helps your body absorb more of it than taking one large dose on an empty stomach.
What if I am pregnant or breastfeeding?
Pregnant people need 85 milligrams per day, and breastfeeding people need 120 milligrams per day. Most prenatal vitamins include vitamin C, but talk to your doctor about what amount is right for you, since needs can vary.
Does cooking destroy vitamin C in vegetables?
Heat does break down some vitamin C, so raw vegetables keep more of it than cooked ones. But cooked vegetables still have vitamin C, and cooking can make other nutrients easier for your body to absorb. Eating both raw and cooked vegetables is the best approach.