Losing Muscle Without Trying? Support Muscle Maintenance

Reviewed by SOMA HEALTH's Medical Research Team

Muscle rarely disappears in a dramatic way. More often it slips quietly: a jar that is suddenly harder to open, a staircase that leaves you a little more winded, a body that looks softer despite no real change in habits. If you have noticed muscle fading without trying, this guide explains what is happening and where urolithin A fits, honestly.

Gradual, age-related muscle loss is common enough to have a name, and understanding the mechanism behind it is the first step to supporting your muscle intelligently. What follows walks through the biology, the human evidence for urolithin A, its genuine limits, and, importantly, when muscle loss is a reason to see your doctor rather than reach for a supplement.

Why muscle can slip away with age

Starting in your thirties and accelerating later in life, adults tend to lose muscle mass gradually if nothing is done to counter it, a process associated with aging and reduced activity. Beyond the mirror, muscle matters for strength, balance, metabolism, and independence, which is why maintaining it becomes more important, not less, as the years add up.

Part of the story is cellular. Muscle is exceptionally energy-hungry tissue, densely packed with mitochondria, the structures that turn nutrients into usable energy. With age, the body's ability to keep those mitochondria in good repair, clearing out worn ones and maintaining a healthy pool, tends to decline. That clean-up process is called mitophagy, and when it becomes less efficient, muscle cells can be left working with a less capable energy supply. This is the biological thread that connects urolithin A to muscle. Our primer on mitochondrial health lays out the system if it is new to you.

Where urolithin A comes in

Urolithin A is a gut postbiotic. When you eat foods rich in ellagitannins, mainly pomegranate, walnuts, and certain berries, some gut bacteria can convert them into urolithin A. But only some microbiomes carry the bacteria needed, so two people with identical diets can end up with very different levels. That is the core reason a standardized supplement exists: it delivers a consistent dose no matter what your gut produces. Our full urolithin A guide covers the biology in depth.

What ties urolithin A to muscle specifically is its studied support of mitophagy. By supporting the recycling of worn-out mitochondria, the research explores whether muscle cells can maintain a healthier energy supply, which is a structure and function idea about supporting a normal process, not a claim to treat muscle-wasting conditions.

What the human evidence shows

This is the area where urolithin A has its strongest human support, so it is worth being precise. In a randomized trial of middle-aged adults published in Cell Reports Medicine (Singh 2022), four months of urolithin A at 500 mg and 1,000 mg per day was associated with improvements in muscle strength and exercise performance. In older adults, a randomized trial in JAMA Network Open (Liu and D'Amico 2022) reported improved muscle endurance over roughly four months. And the first-in-human study in Nature Metabolism (Andreux 2019) established that the compound was safe and well tolerated up to 1,000 mg per day, while detecting a mitochondrial gene-expression signature in muscle-relevant tissue. For a focused look, see our page on urolithin A for muscle.

More recent human work reinforces the exercise angle. An 8-week randomized trial in resistance-trained men (Journal of the International Society of Sports Nutrition, 2024) and a 2025 randomized trial in distance runners extended the research into fitter, active populations. A 2025 trial in Nature Aging also reported support for immune-cell mitochondrial health in midlife adults over about 28 days. Across these studies, the safety record was consistent over durations up to about four months. If you want the study-by-study detail, our summary of the urolithin A clinical studies lays it out.

Honest limitations and what preclinical means

The muscle evidence, while the strongest in the urolithin A field, still comes from a modest number of trials lasting months rather than years, and a 2024 systematic review in Ageing Research Reviews concluded the human evidence for targeting aging is still emerging. It is also worth separating human findings from earlier-stage work. The original muscle observations in animals, along with mitophagy and lifespan effects in the worm C. elegans, came from preclinical research (Ryu 2016, Nature Medicine), meaning laboratory and animal studies not yet confirmed in humans. Related work on joint and cartilage support in osteoarthritis models (D'Amico 2022, Aging Cell) is likewise preclinical. These are promising leads, not established human muscle claims, and they should be read that way.

There is a more important limit. Urolithin A supports a normal biological process; it does not treat any medical condition, and it is not a substitute for the two things with the deepest evidence for muscle: resistance exercise and adequate protein. Just as critically, muscle loss that is rapid, unexplained, or accompanied by weakness, unintended weight loss, or difficulty with daily tasks is not a supplement problem. This guide is educational and is not a treatment. Unexplained muscle loss can signal an underlying condition and deserves prompt evaluation, so please see your doctor rather than trying to manage it on your own.

How to support muscle the evidence-based way

Think of urolithin A as one supporting piece inside a foundation that does the heavy lifting. Resistance training is the single most effective lever for maintaining and building muscle at any age, even two to three focused sessions a week. Adequate dietary protein, spread across the day, gives your body the raw material to maintain muscle. Sleep supports the recovery and repair that make training count. Against that foundation, if you choose to add urolithin A, treat it as an experiment: the studied range is 500 to 1,000 mg per day, take it consistently, and give it a fair runway of a couple of months, since the muscle trials ran for roughly four. Note a simple baseline, such as a specific strength benchmark, so you can judge honestly. Our notes on how to take urolithin A cover the practical details.

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*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease. This guide is educational and is not a substitute for advice from a qualified healthcare provider.