A vitamin C trial missed its main target. Then the survival numbers came in
What happened
Researchers have published the results of a trial called EVITA, which tested whether a daily vitamin C tablet could help people with very early changes in their blood cells — changes that sometimes, but not always, go on to become a blood cancer. The trial was run by Van Andel Institute in Michigan, United States, together with Rigshospitalet at Copenhagen University Hospital in Denmark. It was led by Peter A. Jones and Kirsten Grønbæk, and the results were published in the journal Cancer in September 2026. It was a phase 2 trial: randomised, double-blind and placebo-controlled. That means 109 patients were split by chance into two groups — 55 took 1,000mg of vitamin C by mouth every day, and 54 took an identical dummy tablet. Neither the patients nor their doctors knew who was in which group. Everyone took their tablet for 12 months. The patients all had either clonal cytopenia of undetermined significance, or a lower-risk myeloid condition. In plain terms, their bone marrow had started making blood cells with a particular fault, but they did not have full-blown leukaemia. The trial's main question was whether vitamin C would slow the growth of those faulty cells. The answer was no. There was no difference between the two groups.
Why this matters
That could have been the end of it. Most trials that miss their main target are quietly filed away. But the researchers kept following the patients. After a median of 33.6 months — nearly three years — they counted how many people in each group had died. There were 11 deaths in the vitamin C group and 24 in the placebo group. That is less than half. On the face of it, that is the kind of number that makes people sit up. There is a reason to take the idea seriously rather than dismiss it. Vitamin C is not a random guess here. It boosts the activity of proteins in the cell called TET enzymes, which help control which genes get switched on and off. When TET enzymes stop working properly, that is a known driver of some blood cancers. So there was a real biological reason to test it, which is different from throwing a supplement at a problem and hoping. The trial also found fewer cases of anaemia, pneumonia, arthritis and bleeding in the vitamin C group, though more stomach and gut problems.
What the evidence actually says
Here is the part that matters most, and it is the part that tends to get lost when a story like this travels. The survival finding was exploratory. That is a specific term, not a polite hedge. It means the researchers were not testing that question when they designed the trial. They looked at it afterwards. Why does that matter? Because if you look at enough measurements after a trial has finished, some of them will look impressive purely by chance. The whole point of naming your main question in advance is that it stops you from going hunting for a good result. The trial named its main question, and its main question came back negative. The trial was also small. With 109 people, a difference of 13 deaths is a striking number of people, but a small number statistically. A handful of deaths landing differently could have changed the picture. The researchers themselves were careful. They said they were "cautiously optimistic that these findings could inform future strategies to intercept leukaemia development", that it is too soon to make recommendations, and that they are hopeful a larger study will give more definitive answers. That is the language of scientists who have found something interesting and know they have not yet proved it. The honest summary: an intriguing signal that now needs a bigger trial designed to test it properly. Not a result to act on.
Practical advice
This is not a reason to start taking vitamin C tablets. These patients had a specific, diagnosed bone marrow condition and were monitored by haematologists for years. Nothing here says that a daily vitamin C tablet does anything for people who do not have that condition. If you have been diagnosed with clonal cytopenia or a lower-risk myeloid condition, ask your haematologist. Do not start a supplement on the strength of a news story. Ask at your next appointment what this trial means for you specifically. They will know the full paper. Tell your pharmacist and your doctor about any supplements you take. This is the single most useful habit in this whole article. Supplements are medicines, and some interact with prescriptions. High-dose vitamin C can also upset the stomach — more gut problems in the vitamin C group was one of this trial's clearest findings. Get vitamin C from food where you can. Oranges, strawberries, peppers, broccoli and potatoes all contain it, and most people in the UK get enough from a normal diet. Learn the phrase 'exploratory finding'. When you see it in a health story, it means: interesting, worth another look, not yet proven.
What to know
A phase 2 trial of 109 people tested 1,000mg of daily vitamin C in patients with early blood-cell changes. It did not slow the growth of the faulty cells, which was the question it set out to answer. In a follow-up look at the data, there were 11 deaths in the vitamin C group against 24 in the placebo group after nearly three years. That is a genuinely interesting signal, it has a plausible biological explanation, and it is not proof. The researchers say so themselves. What happens next is a larger trial designed from the start to test survival. Until then, the right response is curiosity rather than a trip to the supplement aisle. Sources: Medical Xpress, 'Vitamin C linked to improved outcomes in people with precancerous blood disorders', September 2026, https://medicalxpress.com/news/2026-09-vitamin-linked-outcomes-people-precancerous.html; Van Andel Institute, https://www.vai.org/; NHS, 'Vitamins and minerals', https://www.nhs.uk/conditions/vitamins-and-minerals/ This article is for general information and does not replace advice from a doctor, pharmacist or other qualified healthcare professional.
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