What is vitamin U?
It’s not a true vitamin. It’s a compound in cabbage. Small studies from 1949 to 1956 reported ulcers healing fast on cabbage juice. But doctors now treat an ulcer by its cause.
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What is vitamin U?
Vitamin U is an old nickname for S-methylmethionine, or SMM. It’s a vitamin-like compound made from methionine, one of the building blocks of protein.
The name came from the 1940s and 1950s. Doctors saw stomach ulcers heal faster in people eating plant foods rich in it, mainly raw cabbage juice.
It’s not on the NHS list of vitamins. That list runs A, B, C, D, E and K. No UK body sets a daily amount for it.
| Question | Answer |
|---|---|
| What is it? | S-methylmethionine (SMM), a compound made from methionine. |
| Where is it found? | Plant foods. The famous studies used raw cabbage juice. |
| Is it a vitamin? | No. It’s vitamin-like, and not on the NHS vitamin list. |
| Is it a licensed medicine? | No. It isn’t registered as a medicine in any Western country. |
Sources: Ananian 2026 review; NHS
So if a pack says vitamin U, read it as SMM. Then ask the real question: does it do anything?
Does vitamin U heal stomach ulcers?
Nobody can say yet. The early results looked striking. But almost all of them came from one doctor, Garnett Cheney, and they’re over 70 years old.
| Study | What it found | The catch |
|---|---|---|
| 1949: 13 people with ulcers drank fresh cabbage juice | Ulcers healed in about 7 to 10 days on average. | No comparison group. Healing was set against other doctors’ reports of 37 to 42 days. |
| 1952: 100 people drank raw cabbage juice | Pain went within 4 days in 86%. Healing took about 13 to 14 days. | Again compared with other doctors’ reports, not a group on dummy pills. |
| 1956: 53 people at San Quentin Prison, over 3 weeks | Ulcers healed in 22 people on the juice and 7 on dummy pills. The review doesn’t say how many were in each group. | The best design of the three. Still small, and the juice held many other compounds. |
| 2023: 37 adults with gastritis took 300 mg of SMM a day | Symptom scores fell from 15 to 5.5 over 6 months. | Everyone took SMM. No group on dummy pills, so time alone could explain some of it. |
Sources: Cheney 1949; Cheney 1952; Cheney 1956; Drozdov 2023; Ananian 2026 review
Gastritis means a sore, inflamed stomach lining. The 2023 group also followed a diet plan, so the pill wasn’t the only change.
A 2026 review of all the research says the level of evidence remains limited. It calls for proper trials, with people picked at random for SMM or dummy pills.
So if a pack or post promises vitamin U heals ulcers, treat that as unproven. The next section explains why.
Why don’t the cabbage juice results settle it?
Think of a cake that came out well. You can’t tell whether the eggs did it, or the butter, or the oven. Cabbage juice is the whole cake.
It holds vitamin C and many other natural plant compounds. The 2026 review says SMM’s own part could not be isolated.
In many of the trials, people knew they were getting the juice, and groups weren’t picked at random. And the risk that only good results got published is high.
There’s a bigger gap too. The juice studies judged success by the sore shrinking on an x-ray. Today the NHS treats an ulcer by its cause.
The main causes are a germ called H. pylori, or regular use of painkillers like ibuprofen.
So ask for the cause to be found first. A GP can check for H. pylori with a simple breath or poo test.
Is vitamin U safe to take?
We don’t know enough to say. Older reviews and animal studies report low toxicity. But human studies are few and small, so rare side effects may not have shown up.
There’s no UK dose. The 300 mg a day above is just what one study used.
Before you try vitamin U or cabbage juice
- Got ulcer symptoms? See a GP first, so the cause can be found and treated.
- On warfarin? Talk to your doctor before any big change to your diet, like daily cabbage juice.
- Have an ulcer? Don’t take anti-inflammatory painkillers, such as ibuprofen, without speaking to a doctor first.
- Already on ulcer medicine? Keep taking it as prescribed.
- Buying a supplement? Check the label gives the amount of SMM in mg.
Sources: NHS: stomach ulcer; NHS: warfarin
The NHS says green leafy vegetables are high in vitamin K, which can affect how warfarin works. You can still eat them. Your warfarin clinic can advise.
Never stop or change a prescribed medicine without your prescriber. For how to judge any pill, see which supplements are worth taking.
What actually helps a stomach ulcer?
Treatment that matches the cause. Most people recover with treatment.
What usually happens if your GP thinks it’s an ulcer
- 1
Tests
A breath, poo or blood test. Some people have a camera test.
- 2
Treat the cause
Antibiotics for H. pylori, or medicine to cut stomach acid.
- 3
1 week to 2 months
How long treatment usually lasts, depending on the cause.
- 4
Check it worked
You may need tests after treatment.
Source: NHS: stomach ulcer
The camera test is a gastroscopy. A thin tube with a camera goes down your throat into your stomach.
NHS steps to ease an ulcer and stop it coming back
- Eat smaller meals.
- Have your evening meal 3 to 4 hours before bed.
- Skip food and drink that set off your symptoms, which can include fatty or spicy foods, coffee and chocolate.
- Don’t smoke, and don’t drink too much alcohol.
- Try to keep to a healthy weight and take steps to manage stress.
Source: NHS: stomach ulcer
The NHS says to do these after you’ve seen a GP. Looking at other gut remedies? See slippery elm for reflux and IBS and fermented foods and gut health.
When to speak to a GP
The main ulcer symptom is tummy pain. It’s usually high up, may burn and is often worse at night. Get help if:
- Your indigestion doesn’t go away with treatment, or your tummy pain keeps coming back. See a GP.
- You have ulcer symptoms and the pain is getting worse or won’t go, you’ve lost your appetite or weight without trying, or you feel full after a very small amount of food. Ask for an urgent GP appointment or call NHS 111.
- You have ulcer symptoms and it feels like there’s a lump in your tummy, it hurts or is hard to swallow, you keep being sick or you feel tired all the time. Ask for an urgent GP appointment or call 111.
- You’re vomiting bright red blood or vomit that looks like ground coffee, your poo has blood in it or is black, sticky and very smelly, you have severe tummy pain, your tummy hurts to touch, or chest pain started suddenly. Call 999 or go to A&E.
An untreated ulcer can bleed and cause a lack of iron. See the anaemia blood test.