Urolithin A Side Effects: Is It Really Safe to Take?

What Is Urolithin A?

Urolithin A is a natural compound made in the gut when certain bacteria convert polyphenols from foods like pomegranates, walnuts, and berries.

Not everyone can produce it naturally. In fact, only about 40% of people have the right gut microbes for this conversion (2). 

That’s why supplements have become popular, as they deliver Urolithin A directly to the body without relying on the microbiome.

Researchers are interested in Urolithin A because it supports mitochondrial health, which is linked to energy, muscle strength, and healthy aging. 

Think of it as a cellular clean-up crew that helps remove damaged mitochondria so healthier ones can thrive. 

This process may improve endurance and reduce inflammation, but studies are still ongoing.

Is Urolithin A Safe?

Human trials so far show that Urolithin A is safe and well-tolerated at doses between 250 mg and 1000 mg per day (3).

Clinical studies report no significant changes in liver enzymes, kidney markers, or cardiovascular health. 

That’s important because these are the areas most supplements can stress if they are not well tolerated. Participants across different age groups handled it well, and researchers found no signs of toxicity.

That said, safety data only extends to a few months of use. Long-term effects are not yet clear, and more studies are needed to confirm whether daily use over years remains problem-free.

Does Urolithin A Have Any Side Effects?

Most people do not experience side effects from Urolithin A, but mild complaints have been reported in some studies.

The most common issues were temporary and included muscle aches, headaches, or digestive discomfort. These were generally minor, and serious side effects have not been linked to the supplement so far.

What Side Effects Have Been Reported in Studies?

Clinical trials list a handful of mild effects that may occur in some people (4):

• Muscle aches or soreness – sometimes reported as myalgia.

• Headaches – occasional and mild.

• Digestive upset – diarrhea or mild gastrointestinal discomfort.

• Back or limb discomfort – described as mild pain or stiffness.

These events were uncommon, usually resolved on their own, and were not considered serious.

Can Urolithin A Affect Liver, Kidneys, or Heart?

Current studies show that Urolithin A does not appear to harm the liver, kidneys, or heart when taken for a few months at typical doses.

Researchers tracked common lab markers such as liver enzymes, kidney function, and cardiovascular health signals during clinical trials (5). 

Across these studies, no significant changes were reported. This suggests that, at least in the short term, the supplement is generally well tolerated.

Still, the research is limited. Most trials only lasted two to four months and involved small groups of participants. That means we do not yet know how Urolithin A might affect these organs with long-term or higher-dose use. 

People with existing liver, kidney, or heart issues should approach supplementation with extra caution.

Who Should Be Careful With Urolithin A?

Most healthy adults tolerate Urolithin A well, but some groups may need to be more cautious:

• Pregnant or breastfeeding women – there is not enough safety data.

• People with liver or kidney disease – organ function can influence how supplements are processed.

• Those with heart conditions – while no problems have been reported, data is still limited.

• Older adults on multiple medications – the risk of drug-supplement interactions is higher.

• Competitive athletes – should look for third-party tested products to avoid contamination.

Can Urolithin A Interact With Medications?

No confirmed drug interactions have been reported with Urolithin A, but research in this area is still very limited.

Because Urolithin A influences mitochondria and inflammation pathways, it could theoretically overlap with medications that target similar processes. 

This includes anti-inflammatory drugs, blood thinners, or treatments for metabolic and cardiovascular conditions. 

So far, clinical trials have not shown any harmful interactions, but they were not designed to test this specifically.

If you take prescription medications, especially for chronic conditions, it’s best to check with your doctor or pharmacist before adding Urolithin A. They can review your current treatment plan and decide whether monitoring or adjustments are needed.

How Can You Take Urolithin A Safely?

You can lower the risk of side effects by being thoughtful about how you use it:

• Start with a lower dose (250–500 mg daily) to see how your body responds.

• Follow product instructions carefully instead of increasing the amount on your own.

• Take it consistently for the best chance of seeing benefits, but pause if you notice unusual symptoms.

• Track your health by paying attention to muscle aches, digestive changes, or headaches.

• Consult a healthcare professional before starting if you have chronic health conditions or take prescription medications.

Can You Get Urolithin A Naturally From Food?

Urolithin A itself is not found in food, but your body can make it when gut bacteria break down compounds called ellagitannins. These are present in foods like pomegranates, strawberries, raspberries, blackberries, and walnuts.

The catch is that not everyone can produce Urolithin A. Only about 30–40% of people have the right mix of gut microbes to make it consistently. 

Even if you eat a diet rich in ellagitannins, your ability to convert them into Urolithin A depends on your microbiome. 

That’s one reason why supplements have become popular, since they bypass this variability and provide a direct source.

Final Words

Research so far shows that Urolithin A is generally safe, with only mild side effects reported in a few cases. Studies have not found major concerns for liver, kidney, or heart health, though long-term safety is still being studied.

For most people, it looks like a low-risk supplement that may support muscle and cellular health. 

Still, it’s best to start with modest doses, monitor how you feel, and check with a healthcare professional if you have underlying health issues or take medications.

FAQs

Does Urolithin A cause muscle pain?

Some participants in clinical trials reported mild muscle aches or soreness, often described as myalgia. These cases were rare and typically resolved without treatment. Serious or long-lasting muscle pain has not been linked to Urolithin A.

Can Urolithin A upset your stomach?

A small number of people experienced digestive issues such as diarrhea or mild discomfort. These side effects were not common and usually improved on their own. Most users tolerated the supplement without any stomach problems.

Is it safe to take Urolithin A every day?

Daily use of Urolithin A at studied doses (250–1000 mg) appears safe for periods of up to four months. No major safety concerns have been reported so far. However, long-term daily use has not yet been fully studied, so caution is recommended.

Can I take Urolithin A with NMN or resveratrol?

There is no evidence showing harmful interactions between Urolithin A and other popular longevity supplements like NMN or resveratrol. Many people choose to combine them for potential complementary benefits.

Is Urolithin A safe for older adults?

Clinical studies in older adults have found Urolithin A to be safe and well-tolerated. It has even been studied for its potential to support muscle endurance in this age group. Those with chronic health conditions should consult a doctor before starting.