Does TUDCA Make You Poop? Bowel Changes Explained

Some people do notice looser or more frequent stools when they start TUDCA, and the medicine labels list pasty or liquid stools as a possible side effect. In a year-long placebo-controlled trial, mild diarrhea was about as common on TUDCA as on placebo, and constipation was not recorded as a side effect of TUDCA in the studies we could read.

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Ask in an online gallbladder forum whether TUDCA changed someone's bowel habits and you will get mixed answers, from looser stools to constipation. It is a common question when people start, and it is easy to see why it causes confusion.

This guide sets out what the trials actually recorded about bowel changes on TUDCA, why bile acids and bowel habit are linked in the first place, what stool color can and can't tell you, and when a change needs a doctor rather than a wait-and-see approach.

Does TUDCA Make You Poop?

Some people notice looser or more frequent stools on TUDCA, especially when they first start. The Italian medicine label lists pasty stools or diarrhea among possible side effects, and the labels describe liquid stools as rare [1, 2]. The protocol of a large ALS trial notes that earlier ALS trials reported soft stools or brief diarrhea after the first doses [3].

In the trials that compared TUDCA with placebo, the results varied. In a year-long trial in people with ALS taking 2 g a day, mild diarrhea occurred in 2 of 15 people on TUDCA and 2 of 14 on placebo [4]. In a 16-week trial in people with progressive multiple sclerosis, also taking 2 g a day, diarrhea was recorded in 3 of 26 people on TUDCA and none of 21 on placebo; digestive side effects overall numbered 10 on TUDCA and 4 on placebo, a difference that wasn't statistically significant [5]. None of these trials was in people without a gallbladder.

Can TUDCA Cause Diarrhea?

It can in some people. In an Italian registry of 86 people with ALS, diarrhea was the side effect recorded most often, in 12 people, and three of them stopped TUDCA because of it [6]. In a small six-week study of 13 people with ulcerative colitis, published as a preprint, two people taking 1,750 to 2,000 mg a day had one or two extra bowel movements a day, for 3 and 14 days [7].

Two of the labels say to lower the dose if diarrhea occurs and to stop if it continues [1, 2]. A few people notice looser stools when they first start; take it with a meal, as directed. If loose stools continue, stopping shows whether TUDCA is the cause.

Can TUDCA Cause Constipation?

In the trials we could read, the only case of constipation was in a placebo group [5]. None of the three TUDCA medicine labels names constipation, though all list occasional bowel irregularity, without saying in which direction, that usually settles as treatment continues [1, 8, 2].

Even so, some people in online forums describe constipation after starting TUDCA. Trials don't always record minor complaints, so that isn't ruled out. Diet, fiber, fluids and other supplements started at the same time can all change bowel habits too.

Why Do Bile Acids Affect Bowel Habits?

Bile acids are normally recycled. About 95% are reabsorbed near the end of the small intestine and returned to the liver on each pass [9]. The ones that reach the colon can change how it behaves: they can make the colon lining more permeable and speed up transit [10].

Not all bile acids act the same way. In a classic study in people, deoxycholic acid made the colon secrete water at lower concentrations, chenodeoxycholic acid at higher ones, and cholic acid not at all [11]. We found no comparable study in people testing UDCA or TUDCA, so those findings can't be applied to TUDCA.

Is It TUDCA or Something Else?

When your bowel habits change after starting TUDCA, it is tempting to blame the newest thing. Often several things changed at once. Coffee can stir the colon within minutes in some people, whether or not it is decaf [12], and changes in fiber, meal size or other supplements started the same week can all shift how often you go.

A simple way to sort it out is to keep a short note for a week or two: what you ate, when you took TUDCA, and how your stools were. If a change lines up with TUDCA rather than with meals or drinks, that may point to the supplement; if not, the cause may lie elsewhere. In a small trial of 40 people with chronic constipation, prunes improved bowel movements and stool consistency more than psyllium [13], which is worth knowing if constipation is the problem.

Are Bowel Changes Normal After Gallbladder Removal?

Bowel changes are common after gallbladder removal, whatever you take. Loose stools after eating may last four to eight weeks, sometimes longer [14], and in one study 47% had loose stools at one month after surgery and 33% at three months [15]. Bile acid diarrhea is a common cause of lasting diarrhea after gallbladder removal [16], and it has its own tests and treatments [17].

That matters when you start TUDCA in the months after surgery, because changes you notice may be part of your recovery rather than a reaction to the supplement. Our guide to diarrhea after gallbladder removal explains the causes and what helps.

What Can Stool Color Tell You?

Stool color reflects what you eat and how quickly food moves through. Green stools can come from fast transit, yellow from excess fat, and pale stools can mean too little bile is reaching the gut or a bile duct is blocked [18]. We found no study that recorded stool color in people taking TUDCA, so there is no evidence on whether it changes color either way.

Our guide to poop after gallbladder removal covers what is normal, and the warning signs are listed below.

When Should a Bowel Change Worry You?

Some changes need a doctor promptly [19, 14, 20]:

• pale, clay-colored or gray stools with dark urine or yellowing of the skin or eyes
• a fever over 101°F, or pain that is severe or getting worse
• diarrhea that lasts more than two days, six or more loose stools a day, or signs of dehydration
• blood in the stool

Black, tarry stools can mean bleeding, and MedlinePlus advises calling 911 or going to the emergency room [21].

In Summary: TUDCA and Your Bowels

Some people notice looser or more frequent stools when they start TUDCA, and the labels list loose stools as a possible side effect, while constipation wasn't recorded as a side effect on TUDCA in the studies we could read. The trials that recorded bowel changes were in people with other conditions, not after gallbladder removal, and two labels advise lowering the dose or stopping if diarrhea continues.

Dr.Primal's TUDCA is made for life after gallbladder removal and taken with meals, to support healthy bile flow and fat digestion when richer meals feel heavy. After gallbladder removal, bowel changes have many causes, so change one thing at a time. If you are working out what is behind your symptoms, our digestion quiz is a quick way to put your symptoms and habits in order.

This article is for general education and is not a substitute for advice from your doctor. TUDCA is sold as a dietary supplement. 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.