A pill millions of men already take for erectile dysfunction just showed a surprising side effect in the lab: it helped muscle cells grow and survive longer.
Quick Take
- Italian researchers found tadalafil, the active ingredient in Cialis, boosted growth and survival of mouse muscle precursor cells in a lab dish.
- The seven-day study, published in Molecular Biology Reports on October 10, 2026, also found the drug delayed those cells from maturing into full muscle fibers.
- The work was done entirely in mouse cells, not in people, so no one can yet say it builds muscle in aging men.
- The finding echoes earlier research showing related drugs affect blood flow and bone mass in older adults.
What The Italian Study Actually Found
Researchers at the University of Rome Foro Italico treated mouse muscle cells called C2C12 myoblasts with a low dose of tadalafil for up to seven days. They tracked how the cells grew, survived, and matured over that week. The result: more cells proliferated, more cells survived, and fewer cells died at every point the team measured, compared to untreated cells.
Muscle precursor cells matter because they are the raw material the body uses to repair and build muscle tissue. When a muscle gets damaged, through exercise, injury, or just the wear of aging, these early-stage cells step in to patch things up. More of them surviving longer sounds like good news for anyone worried about shrinking muscle mass later in life.
The Catch Buried In The Data
The same experiment also found tadalafil slowed down how fast those precursor cells matured into finished, working muscle fibers. In plain terms, the drug grew the raw supply of repair cells but put the brakes on turning that supply into actual new muscle. More building blocks does not automatically mean more finished product.
That tension is the whole story in a nutshell. A drug already sitting in millions of medicine cabinets showed it can push cellular machinery in a muscle-friendly direction, while also showing it slows a separate step in that same process. Both effects happened in the same seven-day window, in the same petri dish, to the same batch of cells.
Why This Fits A Known Pattern With This Drug Class
Tadalafil belongs to a group of drugs called PDE5 inhibitors, which also includes sildenafil, the active ingredient in Viagra. Scientists have already shown that drugs in this class do more than treat erectile dysfunction. Earlier research found tadalafil and a related drug, vardenafil, increased bone mass in animal studies through effects on both the body and the brain.
Human studies of sildenafil add another layer. Researchers found that boosting the same chemical signal these drugs target increased blood flow and oxygen delivery to working muscle in older men, but not in younger men. That age-specific pattern lines up with why scientists keep circling back to these drugs when studying muscle aging, even though a blood flow boost in a lab test is a long way from proven muscle gain in daily life.
What Men Over 40 Should Actually Take From This
No one involved in this research is suggesting men start taking Cialis to build muscle. The study used mouse cells in a dish, not human patients, and the drug’s own data shows a tradeoff between growing precursor cells and finishing the job of making mature muscle fibers. Experts quoted on the findings have been clear that this does not prove the drug builds muscle in people.
Still, the discovery adds a genuinely interesting data point to a growing pile of evidence that erectile dysfunction drugs may have effects reaching well beyond their original purpose. Muscle loss is one of the most stubborn problems of aging, hitting strength, balance, and independence for millions of men every year. A cheap, widely available pill nudging the biology of muscle repair, even in early lab work, is worth watching closely as research moves forward.
The honest summary: this is a real finding from a real published study, and it points somewhere promising. But cell cultures in a lab are the first rung on a very long ladder before anything reaches a doctor’s prescription pad for muscle preservation, and researchers themselves say more work is needed before drawing conclusions about aging men.
UNEXPECTED UPSIDE: Researchers in Italy discovered that tadalafil — the active ingredient in the erectile dysfunction drug Cialis — boosted the growth and survival of muscle precursor cells in a lab study using mouse skeletal muscle cells.
The seven-day experiment, published in… pic.twitter.com/oetqIkfY0S
— Fox News Health (@foxnewshealth) October 13, 2026
For now, the takeaway is curiosity rather than a prescription change. Men managing muscle loss as they age should keep leaning on proven tools, resistance training, adequate protein, and medical guidance, while scientists chase down whether this unexpected muscle signal holds up outside a petri dish.
Sources:
foxnews.com, health.ltn.com.tw, us.headtopics.com, pmc.ncbi.nlm.nih.gov, link.springer.com
