Our story • Our ingredients • Our standards
About Tarsul: Cream of Tartar and MSM, Kept Simple
Tarsul is a small, family-run supplement company in San Diego. We make one thing, with two ingredients, and we try to explain it honestly.
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Tarsul at a glance
- Founded in 2010 by Russ Guillemot in San Diego, California.
- Two ingredients: cream of tartar, a natural source of potassium, and MSM, a sulfur compound found in many foods.
- No fillers and no proprietary blend. Available as capsules or powder.
- A dietary supplement, not a medicine. 30-day money-back guarantee on every order.
How Tarsul Started
In 2008, Russ Guillemot was dealing with a health problem of his own and doing what most of us do: searching for answers late at night. Along the way he came across an older patent, filed in 1989, describing a simple oral mixture of sulfur and cream of tartar. Both ingredients were easy to find, so he bought them and tried the combination himself.
It made a real difference for him. That is one person’s experience, not a clinical study, and we never present it as proof of anything. But it was enough to make him curious about why two such ordinary ingredients had been paired for so long, and why almost nobody talked about them anymore.
In 2010 he started Tarsul to make the pairing easy for other people to try. The name simply joins the two ingredients: Tar for cream of tartar and Sul for sulfur. Tarsul uses MSM as its sulfur source.
What Is in Tarsul
Cream of tartar is potassium bitartrate. As grape juice ferments into wine, tartaric acid and potassium from the fruit crystallize inside the barrel, and those crystals are purified into a fine white powder (University of Illinois Extension). The FDA lists it as a food ingredient that is Generally Recognized as Safe (21 CFR 184.1077). By weight it is roughly a fifth potassium, which is why we describe it as a natural source of that mineral.
MSM (methylsulfonylmethane) is a sulfur compound found in small amounts in many foods. It is widely used in supplements and is generally described as well tolerated in research reviews (Butawan et al., Nutrients, 2017).
That is the whole formula. It is made mainly from cream of tartar, with a smaller amount of MSM. The suggested use is on the dosage and ingredients page, and the label on your bottle always comes first.
How We Talk About Health
People sometimes ask why our site does not list all the conditions Tarsul is good for. The honest answer is that Tarsul is a dietary supplement, and no supplement should be sold as a fix for a disease. Earlier versions of this site said more than we could support, and we have rewritten them.
Today we try to follow a few simple rules:
- We explain what the research says, including when it is thin or mixed, and we link to the sources so you can read them yourself.
- Our health guides start with the steps that have the strongest evidence, such as diet, movement, and seeing a doctor, before Tarsul is mentioned at all.
- When something is a common observation rather than a finding, we say so.
- If we cannot source a claim, we leave it out.
If you are dealing with a health problem, please start with your own clinician. Our guide to our 16 health topics is a good place to read more.
A Note on Potassium Safety
Cream of tartar is a concentrated source of potassium. At the label amount that is fine for many healthy adults, but not for everyone. Much larger amounts, taken at once, have caused dangerously high potassium levels in published case reports (Medical Journal of Australia, 2025). Please talk with your doctor before you start if you have kidney problems, take an ACE inhibitor, an ARB, or a potassium-sparing diuretic, or are pregnant or nursing (NIH Office of Dietary Supplements). Never take more than the label suggests.
A Small Company, On Purpose
Tarsul is family-run. We do not have a big advertising budget or celebrity endorsements, and we do not want them. What we have is one product, made the same way for more than fifteen years, and people who answer the phone.
Some health practitioners order Tarsul wholesale for their own patients. Dr. John Parks Trowbridge, M.D., an integrative physician in Texas, has bought Tarsul by the case for more than ten years. He is a customer, not a formulator or a paid spokesperson, and he has no financial interest in the company.
Every order comes with a 30-day money-back guarantee. If Tarsul is not right for you, contact us within 30 days of delivery for a full refund, and you do not need to return the product. The details are in our terms of sale.
Talk to Us
A real person at Tarsul reads every message. Call 619-500-4403, email info@Tarsul.com, or use the form below.
When you are ready, you can see Tarsul capsules and powder. Orders over $50 ship free.
Have a Question? Ask Us
Search our guides, or send us a note. A real person at Tarsul reads every message.
Frequently Asked Questions
Who started Tarsul?
Russ Guillemot started Tarsul in San Diego in 2010, after finding the sulfur and cream of tartar pairing in 2008 while looking for answers to a health problem of his own. He still runs the company and writes much of what you read on this site.
What does the name Tarsul mean?
It joins the two ingredients: “Tar” from cream of tartar and “Sul” from sulfur.
What is in Tarsul?
Two ingredients: cream of tartar (potassium bitartrate) and MSM (methylsulfonylmethane). There are no fillers and no proprietary blend. The capsules and the powder contain the same two ingredients.
Is Tarsul a medicine?
No. Tarsul is a dietary supplement. It is not intended to diagnose, treat, cure, or prevent any disease, and it is not a replacement for care from your own doctor.
Who should check with a doctor before taking Tarsul?
Anyone with kidney problems, anyone taking an ACE inhibitor, an ARB, or a potassium-sparing diuretic, and anyone who is pregnant, nursing, or managing a medical condition. Cream of tartar is a concentrated source of potassium, so these questions matter.
What if Tarsul is not right for me?
Every order comes with a 30-day money-back guarantee. Contact us within 30 days of delivery for a full refund, and you do not need to send the product back.
Sources
University of Illinois Extension. Cream of tartar: From winery byproduct to baking essential.
Code of Federal Regulations. 21 CFR 184.1077, Potassium acid tartrate.
Butawan M, Benjamin RL, Bloomer RJ. Methylsulfonylmethane: Applications and Safety of a Novel Dietary Supplement. Nutrients. 2017;9(3):290.
NIH Office of Dietary Supplements. Potassium: Fact Sheet for Health Professionals.
Ng DYL, et al. Hyperkalaemic cardiac arrest due to cream of tartar ingestion. Medical Journal of Australia. 2025;222(11).
About this page — last reviewed October 2026
Written by Russ Guillemot, founder of Tarsul. Tarsul is a family-run dietary supplement company in San Diego, California, selling since 2010. We are not physicians, and nothing on this page is a diagnosis or a treatment plan. Where we cite research, we link to it so you can read it yourself.
Tarsul · 2307 Fenton Parkway #107-42, San Diego, CA 92108 · 619-500-4403 · info@tarsul.com
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.