Vitamin C ampoules — what they contain, which doses are used and what an IV drip changes

Injectable vitamin C in ampoules is among the most searched-for injectable forms in Romania. This article explains what the ampoules contain, which doses are used and — the useful part — why the oral form cannot reach, however much you take, what an IV drip reaches.

What the ampoules contain

The active substance is ascorbic acid. The usual strengths in ampoules are in the order of 100–200 mg per millilitre for the products in the ANM Nomenclature (the register of medicines authorised in Romania), and pack sizes differ between manufacturers. They are given intramuscularly or intravenously, depending on the dose and the indication.

High doses are not given by injecting ampoules directly: they are diluted in a solution for infusion and given slowly. This is exactly the same logic as with any substance at a high dose — concentration and rate matter, not just the amount.

Which ampoules are authorised in Romania today

We checked the Nomenclature of the National Agency for Medicines (ANM), in the version updated on 11 September 2026. Under ascorbic acid solution for injection, it lists:

Two things follow from the list. First: all of them are listed as prescription-only — vitamin C ampoules are medicines, not supplements. Second: a 5 g dose means the contents of ten 500 mg ampoules. Hence the rule: at amounts like these, ampoules are not injected one after another; a diluted infusion is prepared.

The list changes over time; what is actually available at any given moment is confirmed by the pharmacist, and you check the exact strength in the leaflet of the product.

The ceiling on oral absorption — the part missing from most articles

This is the fact that changes the discussion. Intestinal absorption of vitamin C is saturable: it takes place through transporters with a limited capacity.

The practical consequence: above a certain oral dose, the percentage absorbed falls, and the surplus is eliminated. You can take larger and larger doses without proportionally raising the concentration in your blood — there is a physical ceiling, not a question of product quality.

Intravenous administration bypasses the intestinal transporters completely. That is why plasma concentrations an order of magnitude above what is possible orally can be reached. This is the only certain advantage of the IV drip, and it is a real one.

What does not automatically follow: that those concentrations produce proportional clinical benefits. These are two different claims, with different levels of evidence.

The numbers behind the ceiling

The reference data come from a pharmacokinetic study by the US National Institutes of Health, published in 2004 in the Annals of Internal Medicine, in healthy volunteers. At the same dose of 1.25 g, the peak plasma concentration averaged about 135 µmol/L by mouth and about 885 µmol/L intravenously. The difference grew as the dose increased.

The authors described the concentrations achieved orally as "tightly controlled" by the body. They also note the study's limitation: at very high doses, the values were calculated by modelling, not measured in patients.

The figures explain why an ampoule and a tablet are not interchangeable. They say nothing about who needs high concentrations — nor that high concentrations are beneficial.

What can be said about high doses

High-dose intravenous vitamin C has been studied for decades, in very different settings — from immune support to adjuvant cancer research. What can honestly be said:

• the role of vitamin C in collagen synthesis, in iron absorption and as an antioxidant is established;
• the high concentrations achieved intravenously are measurable and reproducible;
• the clinical effects of these concentrations, in people without a particular condition, have not been demonstrated by a solid body of evidence.

We give it as a supportive protocol, not as a treatment, and we do not promise results.

When more did not mean better: the LOVIT trial

The largest recent randomised trial of intravenous vitamin C, published in 2022 in the New England Journal of Medicine, included 872 adults with sepsis in intensive care who were receiving medicines to support their blood pressure. Half received vitamin C every 6 hours for up to 4 days, and the other half placebo.

The result was the opposite of what was expected: at 28 days, death or persistent organ dysfunction occurred in 44.5% of the vitamin C group, compared with 38.5% of the placebo group.

This is a completely different setting from a drip at the clinic — critically ill patients, weight-based doses, repeated administration. We mention it for one reason only: it shows, in a large and well-conducted trial, that a high plasma concentration does not automatically translate into a benefit. Sometimes the effect can even go the other way.

Who actually has low vitamin C status

A 2020 review of the factors affecting vitamin C levels globally shows that they depend primarily on diet and supplement use — people who take supplements have, on average, better status. Factors associated with lower levels include smoking, body weight, pregnancy and breastfeeding, severe infections, some chronic diseases and socio-economic conditions.

For most people, a good dietary intake and, if needed, an oral supplement are enough. An IV drip does not replace that and is not a shortcut around it.

Precautions that matter

• History of oxalate kidney stones — vitamin C is partly metabolised to oxalate; at high doses, in certain situations, this is a real precaution;
• kidney failure — elimination is impaired;
• G6PD deficiency — a specific contraindication for high intravenous doses, which is checked at the assessment;
• haemochromatosis or iron overload — vitamin C increases iron absorption.

These are not theoretical precautions, and none of them can be ruled out by an online form. That is what the assessment is for.

For the above there are also documented cases in the medical literature: oxalate nephropathy — oxalate crystals deposited in the kidney — after intravenous vitamin C, and acute haemolysis after high doses in people with G6PD deficiency who did not know they had it. They are rare, but they are exactly why the questions about the kidneys and about G6PD are asked before, not after.

If you have diabetes and measure your blood sugar at home

A practical precaution few people know about: vitamin C at high concentrations can interfere with some glucose meters that use test strips. A laboratory study from the Mayo Clinic, published in 2021, tested three hospital-use glucose meters: on two of them, blood glucose readings came out falsely high as the vitamin C concentration rose, and the third displayed error messages. With self-monitoring glucose meters, false readings in both directions have been reported.

What this means in practice: if you have diabetes, say so at the assessment and do not adjust your treatment on the basis of a glucose-meter reading taken during the period of the drip without talking to your doctor.

How we work

We give vitamin C 5 g — 300 RON — diluted, intravenously, after a medical assessment, at the clinic or at home. There is also the combination with glutathione, at 450 RON.

The vitamin C drip takes around 30 minutes, and the combination with glutathione around 45. For anyone who has agreed a series of sessions with the doctor, there is the Glutathione + vitamin C course: 4 sessions, 1,350 RON in total, compared with 1,800 RON paid separately.

We do not sell ampoules and we do not recommend self-administering injectables. More about the protocol: vitamin C IV drip.

Sources

Vitamin C solution for injection — package leaflet (Catena, Romanian pharmacy chain, in Romanian) — composition, strengths, method of administration (check the leaflet of the product actually used).

Serum iron and iron metabolism (Synevo, Romanian lab network, in Romanian) — on the interaction between vitamin C and iron absorption.

Nomenclature of medicinal products for human use — ANM (in Romanian) — the authorised ascorbic acid ampoules, strengths, dispensing status (version of 11 September 2026).

Padayatty SJ et al. Vitamin C pharmacokinetics: implications for oral and intravenous use. Annals of Internal Medicine, 2004 (PMID 15068981).

Lamontagne F et al. Intravenous Vitamin C in Adults with Sepsis in the Intensive Care Unit (LOVIT). New England Journal of Medicine, 2022 (PMID 35704292).

Carr AC, Rowe S. Factors Affecting Vitamin C Status and Prevalence of Deficiency: A Global Health Perspective. Nutrients, 2020 (PMID 32630245).

Cossey LN et al. Oxalate nephropathy and intravenous vitamin C. American Journal of Kidney Diseases, 2013 (PMID 23548555).

Lo YH, Mok KL. High dose vitamin C induced methemoglobinemia and hemolytic anemia in glucose-6-phosphate dehydrogenase deficiency. American Journal of Emergency Medicine, 2020 (PMID 32561141).

Katzman BM et al. Unintended Consequence of High-Dose Vitamin C Therapy for an Oncology Patient: Evaluation of Ascorbic Acid Interference With Three Hospital-Use Glucose Meters. Journal of Diabetes Science and Technology, 2021 (PMID 32506941).

Kimura T et al. Pseudohypoglycemia or hyperglycemia caused by interference with self-monitoring blood glucose measurements in anticancer ascorbic acid therapy. Journal of Diabetes Investigation, 2013 (PMID 24843726).

Informational article. Doses and whether administration is appropriate are decided by a doctor, at the assessment.