Ashwagandha can make you poop more frequently, yes. It has a long traditional history of use for constipation, and modern research points to real mechanisms behind that effect. For most people, the change is mild, but some experience loose stools or stomach upset, especially at higher doses or on an empty stomach.
How Ashwagandha Affects Your Gut
Ashwagandha doesn’t work like a typical fiber supplement or stimulant laxative. Instead, it influences your digestive system through your nervous system. The active compounds in ashwagandha, called withanolides, reduce your body’s stress response by dialing down what’s known as sympathetic tone. That’s the “fight or flight” side of your nervous system. When that calms down, the “rest and digest” side takes over, prompting your stomach to produce more gastrin, a hormone that triggers digestive juices, speeds up stomach emptying, and stimulates the wave-like contractions (peristalsis) that move food through your intestines.
Ashwagandha also appears to increase serotonin activity. Most people associate serotonin with mood, but roughly 90% of your body’s serotonin is actually in your gut. When serotonin levels rise there, it activates the network of nerves lining your digestive tract, directly stimulating both peristalsis and the secretion of fluids into the intestine. More movement plus more fluid equals softer, more frequent stools.
The Stress Connection
If you’re someone whose digestion slows down when you’re stressed, ashwagandha’s effect on bowel habits could be especially noticeable. Chronic stress keeps your body in a sympathetic-dominant state, which diverts blood flow away from your gut and slows motility. That’s why many people get constipated during stressful periods. By lowering cortisol and shifting your nervous system back toward its parasympathetic (“rest and digest”) mode, ashwagandha can essentially remove the brake that stress puts on your digestion. For people who were already regular, this shift might tip things toward loose stools. For people who were backed up from stress, it could feel like welcome relief.
Thyroid Effects and Diarrhea
There’s another, less discussed pathway worth knowing about. Ashwagandha can raise thyroid hormone levels. Animal studies show it increases the main thyroid hormones, T3 and T4, sometimes significantly (one study found T4 levels rose by about 111% in mice after 20 days of supplementation). In healthy human volunteers, ashwagandha has also been shown to elevate free T3 and T4.
This matters because thyroid hormones control your metabolism, including how fast food moves through your digestive tract. When thyroid levels go too high, one of the classic symptoms is diarrhea. In one case report published in Cureus, a patient taking ashwagandha developed thyrotoxicosis (excess thyroid hormone) and experienced diarrhea, fatigue, fever, and weight loss. This is uncommon, but if you notice persistent diarrhea alongside other symptoms like unexplained weight loss, rapid heartbeat, or feeling unusually warm, your thyroid hormones may be part of the picture.
How Common Are Digestive Side Effects?
In clinical trials, digestive side effects from ashwagandha are generally mild and not much more frequent than what people taking a placebo experience. One randomized, double-blind study on a high-concentration ashwagandha extract reported six total adverse events in the supplement group versus five in the placebo group, with constipation being the only gut-related complaint listed. The difference wasn’t statistically significant.
That said, the NIH Office of Dietary Supplements lists stomach upset, loose stools, and nausea among the common side effects. The key word is “mild.” Most people tolerate ashwagandha without significant digestive disruption, but a subset clearly notices a change, and that’s consistent with the mechanisms described above. If your gut is sensitive to begin with, you’re more likely to feel it.
Powder vs. Extract Makes a Difference
The form of ashwagandha you take matters. Raw root powder contains small amounts of dietary fiber (less than 1 gram per typical serving), along with the full spectrum of plant compounds including tannins and saponins, both of which can irritate the gut lining in sensitive individuals. Concentrated extracts, like KSM-66 or Sensoril, strip out much of the plant material and deliver a higher dose of withanolides in a smaller package. This generally means less bulk irritation but a more potent pharmacological effect on your nervous system and hormones.
If you’re experiencing loose stools from a root powder, switching to an extract might reduce the gut irritation. If you’re taking a concentrated extract and having issues, the effect is more likely from the withanolides themselves rather than the fiber or tannins.
How to Reduce Digestive Side Effects
Taking ashwagandha with food is the simplest way to minimize stomach upset. Some people experience discomfort when taking it on an empty stomach, and pairing it with a meal helps buffer the effect. No specific food pairing is required, just eating something alongside your dose is enough.
Starting with a lower dose and gradually increasing also helps your body adjust. If you’re taking 600 mg daily, try splitting it into two 300 mg doses with meals rather than taking it all at once. This spreads the digestive impact across the day. If loose stools persist beyond the first week or two, it’s worth reconsidering the dose or the product form rather than pushing through it.
People with IBS or other functional gut conditions should be especially cautious. Ashwagandha’s ability to boost serotonin activity and increase gut motility could worsen symptoms in someone whose digestive tract is already overreactive. The same mechanism that relieves stress-related constipation can aggravate diarrhea-predominant IBS.