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Limited evidenceGut health

Vitamin U

Vitamin U (S-methylmethionine, from cabbage juice) is not a vitamin, and its ulcer reputation rests on uncontrolled 1950s case series done before Helicobacter pylori and acid-suppressing drugs existed. There is no modern human trial; the animal data are mildly supportive at best.

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What the science says

  • Heals peptic ulcers Limited evidence

    The foundational evidence is Cheney's 1949–1956 reports, including a San Quentin Prison series, describing faster radiographic ulcer healing with fresh cabbage juice or concentrated 'vitamin U' — roughly 7–10 days versus historical averages of 3–6 weeks. These were uncontrolled, unblinded, used historical comparators, and predate the discovery that most ulcers are caused by H. pylori and NSAIDs. No randomized controlled human trial has replicated them.

  • Protects the gastric mucus barrier Limited evidence

    The mechanistic case is real but animal-only: methylmethionine sulfonium chloride increases gastric mucus and mucin content in rats, and a randomized veterinary trial in finishing pigs found vitamin U added to feed reduced gastric ulcer severity. Useful support for plausibility, not evidence of human efficacy.

  • Vitamin U is a vitamin Limited evidence

    It is not. S-methylmethionine is a methionine derivative abundant in cabbage, kale and other brassicas, with no established human requirement, no deficiency state, and no recognition by any nutrition authority. It acts primarily as a methyl donor, overlapping functionally with betaine and methionine.

Dosage & safety

Studied doseHistorical human use was fresh cabbage juice, roughly 1 litre daily in divided doses, or concentrated preparations. Japanese and Korean OTC gastric products supply methylmethionine sulfonium chloride at about 50–150 mg/day, typically alongside antacids. Supplements sold as 'vitamin U' in Western markets vary widely and are often cabbage powder with no standardization of S-methylmethionine content.
SafetyConsidered low risk; cabbage juice and brassica-derived compounds are ordinary food constituents. Practical downsides are bloating and gas from large volumes of cabbage juice, and the goitrogenic potential of very high raw brassica intake in people with iodine deficiency or thyroid disease. It is a methyl donor, so people on methionine-restricted diets or with homocystinuria should be cautious. The most important point is opportunity cost: if you have an ulcer or persistent dyspepsia, the correct step is testing for H. pylori and appropriate acid suppression — treatments with cure rates above 90% — not cabbage extract.

How to take it

TimingWith or shortly after meals, the way the Japanese and Korean gastric products are dosed.
With food?With food.
Worth knowingIf you have an ulcer or persistent dyspepsia, get tested for H. pylori first — eradication cures more than 90% of cases and no cabbage extract competes with that.

Frequently asked questions

Does vitamin U heal stomach ulcers?

The evidence for vitamin U (S-methylmethionine) is limited to uncontrolled 1949-1956 cabbage juice reports that predate the discovery of H. pylori, and no randomized human trial has replicated them. If you have an ulcer, H. pylori testing and appropriate acid suppression cure more than 90% of cases.

Is vitamin U a vitamin?

No. Vitamin U is S-methylmethionine, a methionine derivative abundant in cabbage, kale and other brassicas, with no established human requirement, no deficiency state and no recognition by any nutrition authority. It acts mainly as a methyl donor.

Is cabbage juice good for gastritis?

Cabbage juice, the historical source of vitamin U, is low risk but unproven: its mucus-protecting effects have been shown only in rats and pigs. Large volumes cause bloating and gas, and persistent dyspepsia should be tested for H. pylori rather than treated with cabbage extract.

How much vitamin U should I take?

Japanese and Korean gastric products supply methylmethionine sulfonium chloride (vitamin U) at about 50-150 mg/day, taken with or shortly after meals. Western 'vitamin U' supplements are often unstandardized cabbage powder, so the S-methylmethionine content is unknown.

Scientific references

Where to buy

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