Urolithin A

Most people who search for urolithin A want muscle that keeps up. They describe the same slow slide: stairs that feel steeper, a walk that tires the legs sooner, a strength that quietly dropped a notch without any change in routine. Urolithin A is the compound studied for the mitochondria inside muscle cells, and that's what draws them.

The second group comes from healthy aging. Urolithin A sits in the same conversation as NAD+, SS-31 and MOTS-c, and it stands out there for two reasons. It's a capsule, not an injection, and it has more randomized human trials behind it than most of the compounds it gets shelved next to.

What those trials found is real and modest. In older adults who took it for four months, the hand and leg muscles kept going longer before tiring, and blood markers of inflammation and mitochondrial strain came down. In middle-aged adults, leg strength went up by about 12 percent. Neither trial measured everyday tiredness, which is what a lot of readers are really asking about.

One detail matters for our readers. The four-month trial in older adults enrolled people in their late sixties and up, and about three in four of them were women. So unlike a lot of muscle research, the people in the study look a good deal like the people asking about it, just a decade or two further along.

Not everything moved. In that same trial, the six-minute walk distance improved in both groups, and the gap between urolithin A and placebo wasn't large enough to count. The muscles' top energy output, measured with a scanner, didn't change either. The endurance result is the one that held, and it's the reason people take it.

Every cell runs on mitochondria, small power plants that turn food into usable energy. Like any machinery they wear out, and a healthy cell has a recycling system, called mitophagy, that breaks down the worn ones so new ones can take their place. That clean-up slows down with age, and worn-out mitochondria hang around making less energy.

Urolithin A is studied for switching that clean-up back on. Think of it less as more fuel and more as clearing out the garage so there's room to work. Most of the evidence for the clean-up itself comes from animals and cells, and in people the trials measured the downstream signs: muscle samples showing more of the proteins tied to mitochondrial recycling, and changes in blood markers.

The odd part is where it comes from. You don't absorb it straight from food. Pomegranate, walnuts and some berries carry the raw material, and gut bacteria turn it into urolithin A, and researchers who run the trials note that how much people make on their own varies widely. Giving the finished compound skips that step.

That's also how it fits with the peptides people pair it with. SS-31 is studied for protecting the inner wall of mitochondria you already have, and NAD+ for helping them run. Urolithin A is the one aimed at taking out the worn ones, so people who use more than one describe them as covering different jobs rather than doubling up.

Urolithin A is a capsule or powder you take by mouth, once a day. There's nothing to mix, nothing to inject and no fridge involved, which makes it the simplest compound in the mitochondria group to start. There's no vial to source, no bacteriostatic water to buy and no syringes to count.

We don't have a dosage page for urolithin A, so the only amounts printed here are the ones the human trials used. The first trial in people gave 500 mg or 1,000 mg a day for four weeks to older adults. The four-month trial in older adults used 1,000 mg a day, and the four-month trial in middle-aged adults compared 500 mg and 1,000 mg a day. No label sets a dose, and no study has compared timing, with food or without.

Research peptide vendors don't sell it, so it isn't in our per-milligram comparison. It's sold through supplement brands instead. Mitopure is the form used in the trials, all run with its maker. See Mitopure on Amazon. That's an affiliate link, which means we may earn a commission at no cost to you. Our affiliate policy explains what that does and doesn't buy.

In all three human trials, urolithin A was well tolerated. The first trial's main goal was safety. It gave healthy older adults who didn't exercise much either a single dose or four weeks of daily doses, and it found no safety problems at any amount tested, with the compound showing up in the blood at each one. In the four-month trial in older adults, side effects were no more common than on placebo.

What isn't known is long-term use. The trials ran four months at most, and they enrolled mostly healthy older or middle-aged adults, so pregnancy, breastfeeding and people managing a chronic condition are all outside what's been tested. Nobody has studied how urolithin A sits alongside prescription drugs. All three human trials had scientists from Mitopure's maker on the author list, and independent replication is still limited.

Pomegranate juice, walnuts and berries are the food route, and they're good food regardless. The catch is that your gut bacteria decide how much urolithin A you get from them, and there's no easy way to know whether yours make much. The trials skipped the question by giving the finished compound, which is why the amounts above are for the supplement, not for a glass of juice.

If you're buying it, the basics are the same as for anything else. Check the amount of urolithin A per serving rather than the capsule size, work out what a day at the trial amounts costs, and look for a brand that publishes independent testing for purity. A cheaper capsule with half the urolithin A isn't the cheaper buy, it's just the smaller one.

Yes. In the US urolithin A is sold as a dietary supplement, over the counter, with no prescription. It isn't an approved drug for any condition.

We haven't written a head-to-head page for urolithin A yet. The compounds people weigh it against are the other mitochondria options. SS-31 is aimed at protecting the structure inside existing mitochondria, MOTS-c works as a signal from mitochondria to the rest of the cell, and NAD+ helps the mitochondria you have run. Our guide to urolithin A, SS-31 and MOTS-c covers the order people take them in, and peptides for energy and fatigue covers where to start when you're tired all the time.

Urolithin A is a supplement, not a research vial, and the human trials are short and run by the company that sells it. It's still the best-tested compound in this group.