The German Nutrition Society (DGE) recommends 95 mg of Vitamin C per day for women and 110 mg for men; smokers require noticeably more, at 135 to 155 mg. The German Federal Institute for Risk Assessment (BfR) advises a maximum of 250 mg of additional Vitamin C per day in food supplements, while the European Food Safety Authority (EFSA) considers a total daily intake of up to approximately 1,000 mg to be safe. According to current research, high-dose Vitamin C does not prevent colds, though it may slightly shorten their duration for some individuals. Those who smoke, are under constant stress, or have an unbalanced diet benefit most from targeted supplementation.

How much Vitamin C do you actually need per day?

The German Nutrition Society (DGE) sets its reference values for Vitamin C intake to ensure that a classic deficiency is safely excluded, including an upper safety margin. For healthy adults, this is 95 mg per day for women and 110 mg for men. Pregnant women need slightly more at 105 mg, while breastfeeding women need significantly more (125 mg) because some of the vitamin is passed through breast milk. Smokers have a proven higher requirement due to increased oxidative stress in their bodies and, according to the DGE, should aim for 135 mg (women) or 155 mg (men).

Important context: A genuine Vitamin C deficiency with symptoms like scurvy is practically non-existent in Germany today. Just 10 mg per day is sufficient to prevent this classic deficiency disease. The DGE reference values are therefore intentionally set much higher than the absolute minimum and are easily achievable through a normal diet—for example, with half a red bell pepper and a glass of orange juice, or by consuming potatoes, spinach, and an apple throughout the day.

95 mg

Women

110 mg

Men

135-155 mg

Smokers

How can you meet your needs without supplements?

Before considering a food supplement, it is worth checking your plate. Vitamin C is found in a surprising number of everyday foods, often in amounts that cover DGE reference values in a single serving. Sea buckthorn and rose hips top the list, followed by bell peppers, black currants, and parsley. Cabbage varieties like broccoli and Brussels sprouts are also underrated Vitamin C sources, as are citrus fruits, which are well-known but actually not the most potent source in a direct comparison.

Important note for food preparation: Vitamin C is sensitive to heat, light, and is water-soluble. Long cooking times, keeping food warm, or soaking in water can destroy or leach out a significant portion of the content. Raw consumption, quick sautéing, or steaming at low temperatures preserves significantly more Vitamin C than traditional boiling. Those who regularly eat fresh fruits and vegetables and prepare them gently usually reach the DGE reference values without any need for food supplements.

At what point does Vitamin C become a risk? A fact-check on overdosage

Vitamin C is water-soluble, and the body generally excretes excess amounts via the kidneys. This makes a dangerous overdose from food practically impossible. The situation is slightly different with food supplements, as these provide concentrated amounts in isolation. The German Federal Institute for Risk Assessment (BfR) therefore recommends that one should not consume more than 250 mg of Vitamin C per day via supplements in addition to a normal diet. The EFSA considers a total daily intake of up to approximately 1,000 mg—combining food and supplements—to be safe for healthy adults.

At daily doses of around 3 to 4 grams, well above the recommendations, studies report more frequent gastrointestinal issues such as bloating, cramps, and diarrhea. There is also discussion regarding a potential link between very high doses and kidney stone formation in susceptible individuals; study findings are inconsistent, but caution is advised for those with a known tendency toward kidney stones. People with hemochromatosis (iron overload disorder) should be especially careful, as Vitamin C increases iron absorption in the gut; an upper limit of around 500 mg per day is recommended as a guideline here. Anyone with regular tooth contact with pure ascorbic acid, such as through chewable tablets, also risks damaging the tooth enamel.

Does high-dose vitamin C really help against colds?

Hardly any vitamin myth is as persistent as the idea that high-dose vitamin C can prevent a cold or end it quickly in acute cases. The German Nutrition Society clearly states that scientific evidence does not prove that taking high doses of vitamin C supplements—from about 200 mg daily—prevents or cures colds in the general population. The Consumer Advice Center reaches the same conclusion: studies have been unable to determine any relevant effect of additional vitamin C intake on the frequency of colds in the general population.

The situation is more nuanced for people under extreme physical stress, such as marathon runners, skiers, or soldiers on winter maneuvers. In this very specific group, some studies have shown a certain reduction in the duration and severity of colds through regular supplementation. However, no general recommendation can be derived from this for most people's everyday lives. The honest assessment is: Vitamin C is important for a functioning immune system, but it is not a cold medication, and in this case, more is not automatically better.

How does vitamin C actually work in the body?

To understand why the cold myth is so persistent, it helps to look at the actual mechanism. Vitamin C accumulates in high concentrations in white blood cells, the central cells of the immune system, and is required there for their normal function and mobility. It also acts as a water-soluble antioxidant and protects cells from damage by free radicals, which are generated in increased amounts during an immune response. This cell-biological mechanism is well-documented and explains why an actual deficiency weakens the immune system.

The flaw in the marketing world lies in transferring this mechanism to clinical results. A proven mechanism at the cellular level does not automatically mean that more of it will have more effect in practice once the body is already adequately supplied. This is exactly what is seen with vitamin C: the mechanism is real, but the clinical added benefit of an extra dose above the reference value is not for cold prevention in the general population. This distinction between a plausible mechanism of action and a actually proven clinical effect is one of the most common stumbling blocks when reading supplement advertisements—not just for vitamin C.

Which vitamin C advertising claims are actually permitted in the EU?

Unlike many herbal substances, there are actually several health-related claims for vitamin C that the EFSA has scientifically reviewed and approved under the EU Health Claims Regulation. These include: contributing to the normal function of the immune system, normal collagen formation for the function of skin, gums, bones, cartilage, and blood vessels, the reduction of tiredness and fatigue, a contribution to normal psychological function, the protection of cells from oxidative stress, and improved iron absorption from food.

The crucial difference to the marketing language used by many providers lies in the details. "Contributes to the normal function of the immune system" is something different than "prevents colds" or "boosts your immune system." The approved claims describe a supportive contribution to normal bodily functions when supply is adequate, not a therapeutic effect or a promise of a cure. Reputable providers stick closely to this wording, while pure marketing promises often go significantly beyond it and are generally not legally permissible.

When and how should you take vitamin C?

Your gut's ability to absorb vitamin C is limited and decreases as the single dose increases. With individual amounts above about 200 mg, the absorption rate drops noticeably, and the rest is largely excreted unchanged. Those aiming for a higher daily amount, such as smokers, are therefore better off taking two smaller portions throughout the day instead of a single mega-dose. Taking it with a meal is advisable because it is gentler on the stomach and improves the simultaneous absorption of iron from plant-based foods, for example if you combine iron-rich vegetables with a source of vitamin C.

For most people, the time of day is less important than consistency. Vitamin C is not stored in the body in relevant amounts, which is why a daily, consistent intake is more useful than sporadic high doses on individual days. Buffered forms, in which ascorbic acid is bound to minerals, are considered somewhat gentler on the stomach than pure ascorbic acid and are therefore particularly suitable for sensitive individuals.

A practical point often missing in guidebooks: Vitamin C is sensitive to air, light, and moisture. Capsules and tablets should therefore be stored in a dry, dark place, preferably in their original packaging. With open powder containers, it is advisable to close the lid tightly immediately after each use, as moisture can measurably degrade the active ingredient over weeks. Once opened, liquid products should be stored in the refrigerator and consumed within the period stated on the packaging so that the amount actually ingested corresponds to the stated dosage.

Capsules, gummies, or liquid: Which form is right for you?

The dosage form has no influence on whether vitamin C works, but it does affect how well it fits into your everyday life and how precisely you can control the dosage. Capsules allow for the most precise dosage and are usually the cheapest option per milligram. Gummies are more pleasant to take, but often contain slightly less vitamin C per portion and, due to potential fruit acids, should not be combined with brushing your teeth immediately after consumption. Liquid shots often provide a combination of several nutrients at once and are a good option if you do not like swallowing capsules.

For whom is vitamin C supplementation actually worthwhile?

Anyone who eats a varied diet with plenty of fruit and vegetables can generally meet their vitamin C needs without any problems through their normal diet. Targeted supplementation is most likely useful for smokers with their increased requirements, for people in stressful phases of life in which the body processes more oxidative stress, for anyone with an unbalanced diet or little fresh fruit and vegetables in their everyday life, and for athletes under very high physical stress. Even in the cold season, when fresh vegetables end up on the plate less often, supplementation can be a useful safeguard without it being a guarantee against colds. A broader overview of useful measures for the cold season can be found in our guide Strengthening the immune system naturally.

Vitamin C also plays a proven role in the body's own collagen formation, an aspect that is often overlooked when the focus is only on the immune system. Without sufficient vitamin C, your body cannot normally build the structural protein collagen for skin, cartilage, and blood vessels, regardless of how much collagen you additionally eat or drink. This is also the reason why many collagen supplements contain vitamin C; you can read more about this in our separate guide on collagen dosage.

A conscious look at intake is also worthwhile for pregnant and breastfeeding women, though without taking high doses on their own. The DGE sets the requirement during pregnancy at 105 mg and during breastfeeding at 125 mg, because a portion of the vitamin is passed on to the unborn child or through breast milk. Dietary supplementation is fundamentally possible here, but as with any supplement in this phase of life, it should be discussed with a doctor beforehand, especially if other preparations are being taken.

Frequently asked questions

How many mg of vitamin C should I take per day?

According to DGE reference values, 95 mg for women and 110 mg for men; smokers should aim for 135 to 155 mg. These amounts are usually easy to achieve through a balanced diet.

Can you consume too much vitamin C?

Yes, gastrointestinal complaints occur more frequently starting at about 3 to 4 grams per day. The BfR recommends an upper limit of 250 mg of additional vitamin C per day for food supplements, while the EFSA considers a total intake of up to about 1,000 mg to be safe.

Does vitamin C prevent a cold?

No. The DGE clarifies that high-dose vitamin C does not reliably prevent colds in the general population. Only in people under extreme physical stress did studies show a slightly reduced duration of colds.

When is the best time to take vitamin C?

Since absorption capacity decreases with high single doses, it makes more sense to divide the daily amount into two smaller portions, ideally taken with meals.

Which vitamin C advertising claims are scientifically backed?

The EFSA has approved claims regarding the normal function of the immune system, collagen formation, the reduction of fatigue, and cell protection against oxidative stress, among others. Claims such as "prevents colds" are not covered by these.

Do smokers really need more vitamin C?

Yes, due to increased oxidative stress in the body, the DGE recommends 135 mg per day for women who smoke and 155 mg per day for men who smoke, instead of the 95 mg and 110 mg respectively for non-smokers.

Is buffered vitamin C better than pure ascorbic acid?

For sensitive stomachs, yes, because binding to minerals buffers the acid. For most people, efficacy and bioavailability hardly differ from pure ascorbic acid.