What are the side effects of Urolithin A supplement?

November 21, 2025 •

3 min read

Recent clinical studies have shown that Urolithin A is generally safe and well-tolerated. While most individuals experience no issues, it is important to understand what the side effects of Urolithin A supplement might be, as some people may report mild, temporary symptoms such as muscle aches or digestive upset.

Quick Summary

This article explains the known side effects of Urolithin A supplements based on clinical trial findings. It details common mild gastrointestinal and musculoskeletal complaints, discusses the low risk of serious adverse events, and outlines safety precautions like starting with a lower dose and consulting a healthcare provider, especially for individuals with pre-existing conditions or those on other medications.

Key Points

Mild Gastrointestinal Issues: Some users report temporary bloating, gas, or mild stomach upset when first starting Urolithin A.
Possible Muscle Aches: A low incidence of mild muscle aches and pains (myalgia) has been reported in clinical trials.
Occasional Headaches: Some individuals may experience mild and occasional headaches as a temporary adjustment effect.
Rare Allergic Reactions: Although rare, allergic reactions can occur, and users should stop use and consult a doctor if they experience symptoms like itching or swelling.
Generally Safe: Urolithin A has a strong safety profile in clinical trials, with no serious adverse effects reported.
Long-Term Effects Need Study: Research on the effects of long-term and high intake of Urolithin A use, especially concerning organs like the liver and kidneys, is still needed.
Medication Interactions: There is limited research on potential drug interactions, and individuals on other medications should consult a doctor before use.
Minimize Risk: Taking the supplement with food and starting with a lower amount can help mitigate potential mild side effects.

Clinical Evidence on Urolithin A Safety

Clinical research into Urolithin A has consistently reported a favorable safety profile. One significant randomized clinical trial involving older adults found no statistical differences in adverse events between the group taking Urolithin A and the placebo group over a four-month period. Similarly, a 2019 study confirmed that Urolithin A was safe and well-tolerated in single and multiple doses. These findings are crucial, as they provide a strong evidence base for the supplement's general safety in healthy, adult populations.

Mild and Temporary Side Effects

Despite the overall strong safety profile, a small number of participants in clinical studies have reported mild side effects. It's important to note that these issues were generally uncommon and temporary, often resolving on their own as the body adjusted.

Gastrointestinal Upset

Some individuals may experience mild digestive issues, especially when first starting supplementation. These effects are often temporary and can include:

Bloating and gas
Mild stomach pain
Diarrhea
Nausea These symptoms can often be mitigated by taking the supplement with food.

Musculoskeletal Discomfort

In some trials, mild muscle aches and pains, known as myalgia, were reported. In a 2022 study, this was classified as a 'possibly' related side effect, though many similar events were deemed 'unlikely' to be related. Discomfort in the limbs or back has also been reported as a mild, temporary event.

Headaches

Occasional, mild headaches have also been noted in some studies. As with other minor issues, they are typically not serious or long-lasting.

Allergic Reactions

Although extremely rare, allergic reactions are a possibility with any supplement. Symptoms can include itching, a rash, or swelling. If a user suspects an allergic reaction, they should stop taking the supplement immediately and consult a doctor.

Comparison of Potential Side Effects

While overall side effect incidence is low, some studies suggest that mild issues may be more common, though severe reactions are still not linked to the supplement.


Side Effect Category	Lower Intake	Higher Intake
Gastrointestinal	Low incidence; body generally adjusts well.	Slightly higher potential for mild, temporary discomfort.
Musculoskeletal	Very low, though mild muscle ache is possible.	Myalgia (muscle aches) noted in clinical trials but classified as mild.
Headaches	Very low incidence, if any reported.	Occasional, mild headaches reported in some users.
Inflammatory Response	Reduced inflammatory markers in middle-aged adults.	Potentially reduces more inflammatory markers in middle-aged adults.

Long-Term Safety and Medication Interactions

Research on Urolithin A's long-term effects beyond a few months is still ongoing. While short-term clinical trials have not identified major concerns for liver, kidney, or cardiovascular health, long-term use and higher intake still require further study. For individuals with pre-existing liver or kidney conditions, extra caution and medical consultation are recommended.

Similarly, research on Urolithin A's potential interactions with other medications is limited. While no harmful interactions have been confirmed, it is best to consult a healthcare provider if taking prescription medication, especially those affecting metabolic, cardiovascular, or inflammatory pathways.

Conclusion: A Supplement with a Favorable Profile

Urolithin A has a favorable safety profile based on current clinical evidence. The side effects reported have been primarily mild and temporary, with no serious adverse events directly attributed to the supplement. These mild issues, such as gastrointestinal upset or muscle aches, often resolve as the body adapts. However, it is important to adhere to recommended guidelines and consult a healthcare provider, especially for those with existing health conditions or taking other medications, given the limited long-term research and lack of specific interaction studies. A cautious and informed approach can help minimize potential risks while exploring the potential benefits of Urolithin A supplementation.

Here is an authoritative source on the safety assessment of Urolithin A in preclinical studies.

Frequently Asked Questions

Urolithin A is generally considered safe for most healthy adults, with no serious adverse effects reported in clinical studies. However, those who are pregnant or breastfeeding, children and adolescents, and individuals with pre-existing liver or kidney conditions should consult a healthcare provider before use, as research in these populations is limited.

Yes, some people may experience mild gastrointestinal side effects like bloating, gas, or nausea, particularly when they first start taking the supplement. Taking Urolithin A with food can help minimize these digestive discomforts.

Mild muscle aches and soreness, known as myalgia, have been reported by some participants in clinical trials, though these instances were rare and typically resolved on their own. This is considered a mild, temporary side effect.

Occasional, mild headaches have been noted in some studies as a possible side effect, but they are not common and tend to be temporary. Staying hydrated may help mitigate the chances of this side effect.

Allergic reactions to Urolithin A are very rare, but possible. Symptoms like rash, itching, or swelling require immediate medical attention, and you should stop taking the supplement if they appear.

The long-term effects of Urolithin A are not yet fully understood, as most studies have been conducted over a few months. Continued research is needed to monitor for any rare or long-term issues, especially concerning organ health.

Research into drug interactions with Urolithin A is limited. Individuals on prescription medications, particularly for chronic conditions, should consult a healthcare provider to assess potential risks before starting supplementation.

Starting with a lower amount and gradually increasing can help the body adjust and may minimize the occurrence of mild side effects, like digestive upset. Taking the supplement with food may also help.

Urolithin A is not regulated by the FDA as a pharmaceutical drug, but as a dietary supplement. Some formulations have achieved Generally Recognized As Safe (GRAS) status for specific uses in food products.

To reduce potential side effects, start with a lower amount, take the supplement with food, and ensure you are using a product from a reputable source. Paying attention to your body's response and consulting a healthcare professional is always a good practice.