Muscle aging is usually described as a slow and unavoidable loss: less muscle mass, less strength, slower recovery and, eventually, a greater risk of frailty. Exercise remains one of the most powerful tools we have to fight that process. But what if part of the problem is not simply that older muscles receive too little stimulation? What if one of their own repair signals gradually becomes chemically damaged?

A new study from researchers led by Kyushu University points toward exactly that possibility. Published in Scientific Reports in July 2026, the research focuses on hepatocyte growth factor, better known as HGF, and a sulfur-containing compound called lipoic acid trisulfide, or LASSS. The findings are intriguing enough to raise the possibility of future strategies aimed at preserving muscle regeneration as we age. But they are also a perfect example of why exciting laboratory research should not immediately be translated into claims about an anti-aging treatment.

The scientists did not reverse sarcopenia in humans. They did not demonstrate that older people can rebuild lost muscle by taking a supplement. What they found is subtler – and scientifically much more interesting.

Why Muscle Repair Gets Harder With Age

Skeletal muscle is remarkably adaptable. Training can make it larger and stronger, while injury can trigger an elaborate repair process. An important part of that ability comes from muscle satellite cells, a population of resident myogenic stem cells positioned around muscle fibers. Most of the time these cells remain relatively dormant. When muscle tissue receives the appropriate signals, however, satellite cells can become activated, proliferate and contribute to repair and regeneration.

One of the signals involved in waking them up is HGF. Despite its name, hepatocyte growth factor is not limited to the liver. It has important roles in the development, regeneration and repair of several tissues, including skeletal muscle.

When muscle is injured, mechanically stretched or otherwise challenged, HGF can participate in a signaling cascade that activates satellite cells. HGF binds to a receptor known as c-Met. Think of HGF as a molecular key and c-Met as one of the locks involved in initiating the repair response. If the key no longer fits the lock properly, the signal becomes weaker.

And this appears to be one of the problems that develops with aging.

Aging Can Chemically Damage the Repair Signal

The researchers have been investigating a chemical modification called protein tyrosine nitration. During aging, reactive molecules including peroxynitrite can modify particular tyrosine residues in proteins. In HGF, two important sites – Y198 and Y250 – are especially relevant because they are located in regions involved in binding to the c-Met receptor.

When these sites become nitrated, HGF loses some of its ability to bind effectively to c-Met. Previous work by the research group found that age-related HGF nitration was particularly evident in fast muscle fibers. That observation is interesting because fast fibers are also especially vulnerable to age-related atrophy.

This suggests a very different way of thinking about declining muscle regeneration. Aging may not simply mean that the body has fewer repair resources. Some of the molecular instructions telling muscle to repair itself may become progressively damaged.

What Lipoic Acid Trisulfide Changed

The new research investigated whether lipoic acid trisulfide could protect HGF against this deterioration. LASSS belongs to a class of highly reactive sulfur-containing molecules sometimes discussed in the emerging field of supersulfide biology.

The results went beyond simple antioxidant protection. Under the researchers’ experimental conditions, interaction with LASSS made HGF more resistant to nitration-related dysfunction. Even more strikingly, after unreacted LASSS had been removed, the treated HGF showed more than twice the c-Met receptor-binding affinity of the original non-nitrated HGF under the reported assay conditions.

In other words, the researchers were not merely protecting a damaged molecular key. Their experiments suggested that interaction with LASSS could produce an enhanced form of HGF that fitted its receptor more effectively while also becoming more resistant to one form of age-related chemical damage.

Why This Is More Than an Antioxidant Story

At first glance, it would be tempting to explain the result simply by saying that LASSS is an antioxidant that protects HGF from oxidative damage. The experiments suggest that something more specific may be happening.

The researchers also tested glutathione trisulfide, or GSSSG, which has strong redox properties. They additionally tested lipoic acid itself. Neither reproduced the distinctive combination of enhanced receptor binding and nitration resistance observed with LASSS after the experimental wash-out procedure.

This led the researchers to propose that LASSS may interact with or chemically modify HGF itself. The exact mechanism still needs further investigation, but potential targets include disulfide bonds within the HGF molecule. If that hypothesis is confirmed, LASSS would not simply be acting as a chemical shield floating around HGF. It could be altering the protein in a way that changes how it behaves.

And No – This Does Not Mean Alpha-Lipoic Acid Supplements Rebuild Aging Muscle

This distinction is crucial. Lipoic acid trisulfide is not the same molecule as the alpha-lipoic acid commonly sold as a dietary supplement. In fact, ordinary lipoic acid was included as a control in the study and did not produce the same enhancement of HGF receptor binding or nitration resistance.

So buying alpha-lipoic acid after reading about this research would be jumping from one molecule to another and from experimental biochemistry to human supplementation without evidence connecting those steps. The study provides no basis for claiming that commercially available alpha-lipoic acid supplements prevent sarcopenia or recreate the LASSS-HGF effect in people.

That may sound like a disappointing qualification, but it actually makes the discovery more interesting. The researchers appear to have identified a specific molecular interaction rather than simply demonstrating another generic antioxidant effect.

What Happened in the Mice?

The research was not limited entirely to test tubes. The investigators also used a mouse model of disuse-induced muscle atrophy. In this model, unloading the hind limbs creates a period of muscular inactivity. Pre-administration of LASSS prevented the disuse-associated HGF nitration observed by the researchers, whereas the comparison compound GSSSG did not show the same result.

That is important because it demonstrates that at least part of the proposed mechanism can operate in a living animal. But there is still a large gap between preventing a molecular change in a mouse model and treating age-related sarcopenia in humans.

The experiment does not establish that LASSS restores lost human muscle mass, increases strength in older adults, improves walking speed or prevents falls. Those are the kinds of clinically meaningful outcomes that eventually would have to be demonstrated before talking about a therapy for sarcopenia.

Could Protecting Repair Signals Become an Anti-Sarcopenia Strategy?

Potentially – and this is where the study becomes exciting. Much of the discussion around preserving muscle with age understandably focuses on resistance training, adequate protein intake, physical activity and the hormonal and metabolic environment. Those factors remain enormously important.

But muscle maintenance also depends on the tissue's ability to respond to damage and mechanical stimuli. If aging chemically degrades molecules involved in activating muscle stem cells, protecting those signals could eventually become another piece of the puzzle.

The concept is particularly intriguing because it shifts the emphasis from replacing something the aging body supposedly lacks to preserving biological machinery that is already there. Instead of supplying more growth factor, future interventions might conceivably protect or enhance the growth factor the muscle already possesses.

That is still a hypothesis for future therapeutic development, not an available anti-aging intervention. LASSS would need much more research covering pharmacology, dosing, metabolism, safety, delivery, long-term effects and ultimately controlled human trials.

What the Study Really Tells Us

The most compelling message from this research is not that scientists have discovered a compound that makes old muscles young again. They have not. It is that age-related muscle decline may involve damage to specific molecular repair signals – and that such damage might not necessarily be irreversible.

In the laboratory, LASSS produced an HGF form with increased c-Met receptor-binding affinity and greater resistance to nitration-related dysfunction. In mice, pretreatment also prevented the HGF nitration associated with experimentally induced muscle disuse. Those findings provide a biological mechanism worth pursuing.

For anyone interested in fitness and healthy aging, however, the practical advice has not suddenly changed. Resistance exercise remains one of our strongest established tools for maintaining muscle mass, strength and function with age. What this study adds is a glimpse at what may be happening much deeper inside aging muscle – and perhaps a future way of helping its own repair machinery keep working.

Source

Zushi K, Seki M, Mizuochi R, et al. Enhanced HGF with increased receptor affinity and nitration-dysfunction resistance through interaction with lipoic acid trisulfide. Scientific Reports. 2026;16:22053. Published July 24, 2026. DOI: 10.1038/s41598-026-60835-w.