Frequently asked questions
Everything you want to know about Vitamin U
About Vitamin U
The basics
Vitamin U is the common name for S-methylmethionine (SMM), a naturally occurring compound found in cabbage and other cruciferous vegetables. It was named by researcher Garnett Cheney at Stanford in the 1950s, during research into raw cabbage juice and the stomach. The U stands for ulcers. It isn't technically a vitamin by modern definition, but the name stuck.
Not in the strict scientific sense. Classical vitamins are essential nutrients the body can't produce and must get from food. S-methylmethionine doesn't fit that definition. Think of it as a vitamin-like compound: naturally occurring, food-derived, and studied since the 1950s.
It's found naturally in cabbage, kale, Brussels sprouts, and other cruciferous vegetables, and in smaller amounts in celery, asparagus, and spinach. Raw cabbage juice is the most concentrated food source. Each VitaminYOU capsule contains 500 mg, roughly what a litre of the juice would give you.
Your stomach makes acid strong enough to break down food. What stops it breaking down the stomach itself is a thin mucus layer sitting on the stomach lining, keeping the acid off the tissue underneath.
In laboratory studies, S-methylmethionine increased the amount of mucus on the stomach lining. That layer is where it appears to act.
Watanabe et al., reviewed in Ananian et al., Pharmaceuticals 19(5):743, 2026.
Taking it
Dosage, timing and who should ask first
One to two VitaminYOU capsules per day, which is 500 to 1,000 mg of S-methylmethionine.
With food. Consistency matters more than whether you take it in the morning or the evening.
We don't have data on combinations, so we can't tell you either way. If you take prescription medication, ask your doctor or pharmacist before adding anything new.
It's a dietary supplement, sold in the US under the rules that apply to supplements, made in an FDA-registered cGMP-compliant facility, and third-party tested for purity and potency every batch.
If you take prescription medication or are managing a medical condition, check with your doctor before starting.
There isn't enough safety data for use during pregnancy or breastfeeding, so please consult your doctor before taking it.
Everyone is different. Some people notice a difference within days. For others it takes weeks.
The product
What's inside
S-Methylmethionine (Vitamin U), 500 mg per capsule. Three inactive ingredients: hypromellose (the capsule shell), magnesium stearate, and silicon dioxide.
Yes. The capsule shell is made from hypromellose, a plant-derived material.
Yes. VitaminYOU is third-party tested for purity and potency, every batch.
VitaminYOU is manufactured in the United States in an FDA-registered, cGMP-compliant facility.
Yes. S-methylmethionine is built around a sulfur atom. When a little of it breaks down it gives off dimethyl sulfide, which is the same gas that makes cooked cabbage smell like cooked cabbage. That's what you notice when you open the bottle.
Some people also get a light sulfur burp shortly after taking it, for the same reason, much the way fish oil can do. It passes, and taking it with food usually helps.
Heat and air speed that breakdown up and make the smell stronger, so keep the bottle sealed and somewhere cool and dry.
VitaminYOU is a dietary supplement, not a drug. Under US law, dietary supplements are not individually approved by the FDA. Our facility is FDA-registered and cGMP-compliant, and the product label complies with FDA dietary supplement regulations.
Shipping and returns
Orders and delivery
All 50 US states, and Canada.
US shipping is free. Canada is a flat CAD 15. Full details are on our Shipping Policy page.
Orders are processed within 1 to 2 business days. US delivery typically takes 3 to 7 business days after shipment. Canada takes 8 to 10 business days. A note on current delays: USPS is going through a nationwide network reorganization, and occasionally a package sits for several days without a new tracking scan. We're sorry, it's genuinely annoying. These almost always start moving again on their own and arrive. If yours hasn't moved in a week, email us at hello@vitaminyou.shop.
30-day satisfaction guarantee. If you're not happy for any reason, email us at hello@vitaminyou.shop within 30 days of delivery and we'll issue a full refund. You don't need to return the bottle. Full terms are on our Returns and Refunds Policy.
Subscriptions
Subscribe and save
Yes. On the product page, choose deliver every month or every 2 months instead of one-time purchase. You save 10% on every order, not only the first.
Yourself, in about a minute. Click the account icon at the top of any page, enter your email, and we send you a 6-digit code to sign in. There is no password to remember. Then open Subscriptions and click Manage.
Skip moves your next delivery on by one cycle, pause stops deliveries until you start again, and cancel ends it. There is no minimum number of orders and no cancellation fee. We also email you before every charge, so you always have time to decide. Full details are on our Subscription and Cancellation Policy page.
A bottle is 60 capsules. Two capsules a day is a monthly bottle. One a day is every 2 months. You can change it whenever you like.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.