How vitamin C works: what it does in the body

Vitamin C (ascorbic acid) works in the body in two main ways: as an antioxidant, donating electrons to free radicals, and as a cofactor for enzymes involved in collagen synthesis, in the production of carnitine and noradrenaline, and in the absorption of non-haem iron. Humans cannot make it, so you depend on food or supplements. Vitamin C contributes to the normal functioning of the immune system and to the protection of cells from oxidative stress.

Below is the mechanism, what the evidence does and does not show, how much you actually need, what the TuttiBear gummy labels say, and when it is worth talking to a healthcare professional.

What vitamin C is, and why your body cannot make it

Vitamin C is water-soluble. It dissolves in water and is not stored in any meaningful quantity. Most mammals synthesise it in the liver; humans lost that ability somewhere along the evolutionary line and have to get it from the diet. The surplus leaves in your urine — which does not mean very large doses are harmless. They can upset your digestive system.

Severe deficiency (scurvy) appears when intake stays very low for weeks. It is rare in Europe now. Intake below the recommended level, though, is common among smokers and among people whose diets are light on fruit and vegetables. One systematic review of 141 observational and intervention studies in adults found higher vitamin C intake in people following plant-based (vegetarian and vegan) diets than in meat eaters.

The mechanism: what vitamin C is actually doing in there

Two pillars hold the whole thing up: antioxidant action and the job as an enzyme cofactor.

Antioxidant action: handing over an electron

Free radicals are molecules with an unpaired electron, which makes them reactive and capable of damaging lipids, proteins and DNA. Vitamin C donates an electron to them and stabilises them. This is well documented in the lab. In the human body it is messier: vitamin C interacts with other antioxidants, vitamin E among them, and the overall balance depends on each person's nutritional status. The authorised claim in the EU is that vitamin C contributes to the protection of cells from oxidative stress.

Enzyme cofactor: where vitamin C is indispensable

Without vitamin C, several enzymes simply do not work. The best known are the prolyl hydroxylases, which take part in collagen synthesis — collagen being the most abundant protein in the body, present in skin, tendons, blood vessels and bone. Vitamin C is needed for collagen molecules to be stable and properly structured. Without it, collagen is unstable and tissues weaken, which is exactly what happens in scurvy.

Another important role is in the absorption of non-haem iron, the iron that comes from plants. Vitamin C converts ferric iron (Fe3+) into ferrous iron (Fe2+), which the intestine absorbs more easily. Pairing vitamin C-rich foods with plant iron sources — pulses, for instance — is therefore a sensible strategy, particularly for vegetarians and vegans.

Vitamin C also takes part in reactions that produce carnitine and noradrenaline, and in the synthesis of certain amino acids. These are less discussed, but they show the vitamin is involved in far more than immunity.

Does vitamin C actually work? What the evidence shows

For preventing colds, the honest answer is: not really. In a Cochrane meta-analysis of 29 trial comparisons with 11,306 participants, regular vitamin C did not reduce the likelihood of catching a cold in the general population. There was a slight reduction in how long symptoms lasted, but the effect is small and does not justify high doses. Taking vitamin C once symptoms begin showed no consistent benefit in that same meta-analysis.

For skin, the evidence on oral vitamin C is limited. Most studies use specific topical formulations, not gummies. Nobody can promise you that an oral vitamin C supplement will visibly improve your skin.

There is research into vitamin C and chronic disease, but results are mixed and, in many cases, the doses studied are far above what you reach by mouth. It cannot be said that vitamin C prevents or treats any disease. What is known is that deficiency is associated with poorer health — while supplementing people who already have adequate levels does not appear to deliver meaningful extra benefit.

What vitamin C does not do, and why to be wary of those who say otherwise

A lot of claims hang around vitamin C with nothing behind them. It does not make anyone immune to infection. It does not replace a balanced diet and it does not treat illness. And, contrary to what some brands imply, it is not a fat burner and does not speed up your metabolism in any relevant way.

If a supplement promises "detox" or "boosting your defences" without explaining how, be sceptical. European regulation is strict: health claims must be authorised and listed in Regulation (EU) 432/2012. Plenty of popular vitamin C claims were rejected for lack of evidence. That does not make vitamin C useless. It means it does not do what the label implies.

How much vitamin C you need — and how to tell if you are overdoing it

Requirements vary with age, sex and lifestyle. In Portugal the reference intake for adults is around 80 mg a day. Smokers need more, because tobacco raises oxidative stress and lowers vitamin C levels. Pregnant and breastfeeding women also have increased needs.

A medium orange gives you roughly 70 mg; a kiwi, about 90 mg; raw red peppers have more than 150 mg per 100 g. A varied diet can get you there. Supplements are useful when the diet falls short, or when a healthcare professional has identified a specific need.

The safe upper limit for adults is 2000 mg a day. Above that, the risk of diarrhoea, abdominal pain and kidney stones rises. Megadoses have no proven benefit: your body excretes the excess, and side effects become more likely than any gain.

If you take medication or have a diagnosed health condition, speak to a healthcare professional before supplementing. Vitamin C increases non-haem iron absorption, which can be a problem for people with iron overload (haemochromatosis), and very high doses can interfere with some medicines and laboratory tests.

The different forms: ascorbic acid, mineral salts and liposomal

Supplements come in several forms. Ascorbic acid is the most common and the most studied; it is well absorbed but can cause gastric discomfort at high doses. The mineral salts (sodium or calcium ascorbate) are less acidic and may be tolerated better. The liposomal form wraps the vitamin in liposomes, which may increase absorption — but evidence of clinical benefit is limited and the cost is higher.

There is no universally "best" form. Your choice depends on tolerance and budget. What matters is the total dose and how consistent you are. Taking 200 mg of ascorbic acid a day is enough for most people. Taking 1000 mg of liposomal is not necessarily better.

Vitamin C and collagen: the pairing everyone sells

The link between vitamin C and collagen is why so many brands put the two together in beauty supplements. The logic is sound: vitamin C is a cofactor in collagen synthesis, so having both present makes sense. Whether an oral collagen supplement with vitamin C improves skin, however, is not conclusively proven. In a meta-analysis of 19 clinical trials with 1125 participants (95% women, aged 20–70), hydrolysed collagen supplementation showed favourable results for wrinkles, hydration, elasticity and skin firmness. A separate systematic review of 11 trials with 805 participants found improvements in skin elasticity and hydration with collagen (tripeptide, 3 g daily, 4 to 12 weeks). Those studies looked at collagen, not at the specific combination with vitamin C in a gummy.

If you are weighing up a beauty supplement, look at the doses and the form. Collagen Gummies from TuttiBear provide 24 mg of vitamin C per 2-gummy serving (30% of the reference intake) alongside 1000 mg of hydrolysed collagen. That vitamin C dose is enough for the cofactor role, but not for dramatic antioxidant effects. Check the label of whatever you buy and compare the numbers before you commit.

Vitamin C in gummies: what the TuttiBear labels say

The TuttiBear gummies that contain vitamin C deliver moderate doses, designed to top up the diet rather than replace it. Here is the vitamin C per serving across the range:

• Collagen Gummies: 24 mg (2 gummies), 30% of the reference intake
• Skin Hydration & Firmness Gummies: 50 mg (2 gummies), 62.5% of the reference intake
• Daily Detox Gummies: 40 mg (2 gummies), 50% of the reference intake
• Immunity & Defense Gummies with Echinacea: 80 mg (2 gummies), 100% of the reference intake
• Multivitamin Gummies: 20 mg (2 gummies), 25% of the reference intake
• Hair & Nails Gummies: 20 mg (2 gummies), 25% of the reference intake
• Multivitamin Gummies for Kids (+2 years): 10 mg (1 gummy), 13% of the reference intake

Only one of these covers the full reference intake in a serving. The rest are complements, not substitutes for a varied diet. A gummy does not change what vitamin C does inside you — the vitamin is the same molecule either way. What the format changes is adherence: people tend to keep taking something that tastes pleasant, and a supplement you stop taking does nothing at all. That is the honest case for gummies, and it is a modest one.

Interactions worth knowing about

Vitamin C increases non-haem iron absorption. Good news if your iron intake is low; less good if you have iron overload (haemochromatosis). Very high doses can also interfere with certain medicines and laboratory tests. If you take medication or have a health condition, speak to a healthcare professional before you start.

Who should ask a professional first

Pregnancy, breastfeeding, children, medication and diagnosed conditions all warrant professional advice before you begin any supplement. Never give a child a dose without your paediatrician's guidance. If you suspect a vitamin C deficiency, the diagnosis needs to come from a doctor, not from a symptoms checklist online.

The broader safety picture — signs of excess, at-risk groups, interactions — belongs on its own page, and so does the question of vitamin C for children. Read those if either applies to you.

What to do with all this

If your diet is rich in fruit and vegetables, you probably already have enough vitamin C. If it is not, a supplement of 100 to 200 mg a day is a reasonable and safe choice. You do not need megadoses. If your goal is skin, topical vitamin C has more evidence behind it than oral — though even there, results vary from person to person. And if someone tells you vitamin C will "strengthen your immune system" or "flush out toxins", ask to see the study. Vitamin C is essential. It is not a cure, and it was never going to be.