Last reviewed: July 2026
Here's a fun test. Eat a bowl of pomegranate seeds. (Good luck. They always end up on your shirt.) Now go about your day. What your gut does next is amazing. Science took many years to see it.
Inside those seeds are plant chemicals. They are also in walnuts and raspberries. These chemicals are called ellagitannins. Your gut bacteria break them down. Some people's bacteria turn these chemicals into urolithin A. Urolithin A then starts mitophagy (PMID: 27400265). Think of this as your cells' own recycling system.
Scientists who study long life are watching this closely. This post explains the real science. No hype. Just how it works and what studies show.
Your Cells Have a Garbage Problem
Your mitochondria make energy for your cells. Think of them as tiny power plants. They burn food and make ATP. ATP is the fuel for moving muscles, thinking, and everything else.
Here is the problem: power plants wear out. Mitochondria do too. As you age, damaged mitochondria build up inside cells. Damaged mitochondria make less energy. They also leak bad stuff (PMID: 34030963). Scientists now see this as a main reason we age.
Your body has a way to fix this. But it slows down over time.
What Is Mitophagy?
Mitophagy is your cells' way to clean up old mitochondria. The word means "mito" (mitochondria) + "phagy" (Greek for "eating"). Damaged mitochondria get marked. They are then wrapped up and recycled.
Here is the best way to think about it. Imagine a factory manager. Every night she checks the machines. She finds the broken ones. She takes them out. She uses the good parts. She makes room for new machines. When she does her job, the factory runs well. When she slows down, broken machines pile up. Production drops. This happens as we age.
That is mitophagy. It slows down. This is why muscles get tired after age 40 (PMID: 37925671).
Where Urolithin A Comes In
Urolithin A is a postbiotic. Your gut bacteria make it. You do not eat it directly.
The raw material is ellagitannins. These plant chemicals come from pomegranate, walnuts, and raspberries. Special gut bacteria turn them into urolithin A. Your gut then takes it into your blood.
Here is the catch: not everyone's gut does this.
Why Production Varies So Much
Science has found three types of gut profiles. These are called metabotypes. Some people make urolithin A well from food. Others make very little. Some make none at all (PMID: 38329279). The same foods give very different results.
Your metabotype depends on your diet. It also depends on past antibiotic use. Other things play a part too. This is a very interesting puzzle in gut science.
This difference is why scientists started to study urolithin A as a direct supplement.
What the Studies Actually Show
A big 2016 paper in Nature Medicine made urolithin A famous. It found that urolithin A caused mitophagy in animals. It also made a worm, C. elegans, live longer. It made muscles work better in rodents (PMID: 27400265). That study has been used by other scientists over 1,000 times.
Animal studies are a start. Human studies are the real test.
The Human Evidence
A 2022 study looked at middle-aged adults. They took urolithin A for four months. Some took a fake pill. The results: those who took urolithin A gained muscle strength. They also did better in exercise. Their cell powerhouses also got healthier. This was compared to those who took the fake pill (PMID: 35584623).
A second 2022 study looked at older adults. This was in JAMA Network Open. Taking urolithin A made their muscles last longer. It also made their cell powerhouses healthier (DOI: 10.1001/jamanetworkopen.2021.44279).
A 2025 paper showed how it works. It uses a calcium signal (DOI: 10.1080/15548627.2025.2561073). Now scientists know HOW it works. They don't just know THAT it works.
One important thing to note: these are early human studies. The science is real. The results look good. But they do not mean urolithin A stops or cures any disease. The studies do not say that.
Why You're Hearing About It Now
The simple answer: the time is right. The research caught up.
People knew about Urolithin A in the 1970s. But most ignored it. The 2016 Nature Medicine paper changed that. Many years of studies followed. Then the 2022 human studies gave scientists something clear to talk about.
At the same time, people in their 40s and 50s want to know what happens inside their cells. Ideas like mitophagy, NAD+, and cell aging are now common. (No one said "mitophagy" at parties in 2010. They do now.)
Urolithin A has three key things: it's a real compound. We know how it works. There is growing proof from human studies.
How to Support Healthy Mitophagy
You can help your cells clean up. This is true no matter how much urolithin A your gut makes. Here is what the science shows.
Eat foods rich in ellagitannins. Pomegranate, walnuts, and raspberries give the raw materials. Eat them often. Don't just have them for holidays.
Exercise regularly. Both cardio and strength training start mitophagy. A 45-minute walk tells your cells to clean up. This is a free tool most people don't use enough.
Think about eating only at certain times. Not eating for some hours is linked to more mitophagy. When cells are not busy with food, they start cleaning. One caveat: fasting is not for everyone. If you are pregnant, take medication, have diabetes or low blood sugar, or have had an eating disorder, talk to your doctor before you try it.
Look at what studies say about supplements. Not everyone makes urolithin A well from food. A direct supplement might help with this. Learn more and subscribe to our free healthy-aging blog: eternalspringsbio.com/blogs/age-smarter-journal.
Frequently Asked Questions
What foods have a lot of urolithin A? You cannot eat urolithin A directly. Your gut bacteria make it. They use ellagitannins from pomegranate, walnuts, and raspberries. How much you make depends on your gut bacteria.
Is urolithin A safe? Studies in humans so far show no big safety problems. This is at the amounts tested. More research is still happening. Talk to your doctor first. This is real advice, not just words.
Can urolithin A help with muscle loss as you age? Studies suggest it may help older adults. It may boost muscle strength and how long muscles can work.* The research looks good. Urolithin A is not a cure for muscle loss or any health problem.
Is it true that not everyone makes urolithin A from food? Yes, that is true. Scientists have found three different gut types. Some people change food ellagitannins well. Others make very little or none.
How long does it take to see results? The 2022 study lasted four months. It found better muscles and cell powerhouse markers then.* How each person responds can be different.
What to Take Away
- Gut bacteria turn pomegranate chemicals into urolithin A.
- Urolithin A starts mitophagy. This is your cells' way to clean out damaged powerhouses.*
- Human studies show better muscle strength. They also show better endurance and cell powerhouse health.*
- Not everyone makes urolithin A well from food. Gut bacteria are different in people.
- Diet, exercise, and proven supplements all help cells stay healthy.*
Sources
- Ryu D et al. (2016). Urolithin A starts mitophagy. It makes C. elegans live longer. It also makes muscles work better in rodents. Nature Medicine. PMID: 27400265
- Singh A et al. (2022). Urolithin A makes muscles stronger. It helps with exercise. It also improves cell powerhouse health. This was in a study of middle-aged adults. Cell Reports Medicine. PMID: 35584623
- Liu S et al. (2022). How Urolithin A helps muscles last longer. It also helps cell powerhouse health in older adults. JAMA Network Open. DOI: 10.1001/jamanetworkopen.2021.44279
- Souza MTC et al. (2021). How the natural compound Urolithin A affects health, sickness, and aging. Trends in Molecular Medicine. PMID: 34030963
- Jannig PR et al. (2024). Using Urolithin A to start mitophagy. This helps with muscle aging. Calcified Tissue International. PMID: 37925671
- González-Sarrías A et al. (2024). How Urolithin A production drives the effects of pomegranate. This is on gut bacteria. Food & Function. PMID: 38329279
- Roussos A et al. (2025). Urolithin A changes how cell parts talk to each other. It uses calcium-based mitophagy. This helps with healthy aging. DOI: 10.1080/15548627.2025.2561073
*These words have not been checked by the Food and Drug Administration. This product is not meant to find, treat, cure, or stop any disease.
This is for your information only. This is not medical advice. Do your own research. Talk to your doctor. Do this before changing your diet, supplements, or health habits.
About the author — Roger Braun is the founder of Eternal Springs Bio, a NASM Certified Nutrition Coach, and a wellness entrepreneur with more than 14 years of experience in the dietary supplement industry. He earned his Bachelor's Degree in General Studies from Western Illinois University and has spent his career working with nutrition, supplement, and healthy-aging products.
Roger's writing focuses on the science of aging, metabolic health, gut health, immune support, and evidence-based nutrition strategies. He translates peer-reviewed research and supplement industry knowledge into clear, practical guidance for adults who want to better understand how nutrition, lifestyle, and targeted supplementation can support healthy aging in midlife and beyond.
Based on original ideas, research direction, and editorial review by the author, with AI-assisted drafting support.
This article is for informational purposes only — see the full disclosure below.
This article is for informational purposes only and is not medical advice. Do your own research and talk to your doctor before changing your diet, exercise routine, supplements, or health habits. The Food and Drug Administration has not evaluated these statements. If the above article mentions product(s), please know, These products are not intended to diagnose, treat, cure, or prevent any disease.