The primary function of skeletal muscle is to move our limbs. These muscles are attached to our bones and pull on them during contraction. When contracting, muscles consume energy—like a Ford Mustang using fuel to generate propulsion. Like teeth, we only get one set of muscles, so we need to take care of them. Aging and disease can disrupt both the quality and function of muscle. At some point in almost every human being’s life, such impairments may prevent us from going for a round of golf, playing with our grandchildren or even getting out of bed. This issue concerns scientists, especially muscle physiologists like me. The big question we ask is: How can we address disabling loss of physical function? Surprisingly, black pepper may be part of the answer.

Let’s go back to the Mustang. For a long time, scientists believed our muscles to be like a standard car without the aftermarket options of changing the engine or altering fuel economy. Over the past few decades, scientists have discovered an evolutionary switch within our muscles that can turn them more on or off.  Think of this as if you’re placing a larger or smaller engine in the Mustang.

The great mystery of the muscle’s on/off switch holds enormous potential for improving our lives. Very intriguingly, this switch can be flipped by different compounds, leading to activation and inactivation of the primary motor molecule (called myosin). Researchers are using these kinds of compounds to design drugs that can increase or decrease the on/off state of our skeletal and heart muscles. However, we currently do not have any drugs that can flip the switch in skeletal muscles, without also affecting the heart.

My research centers on mapping both good and bad effects of flipping the switch on in skeletal muscles—and I do so using black pepper! Ten years ago, researchers from the University of Padova in Italy revealed that a compound extracted from black pepper called piperine could flip the on switch in skeletal muscles. Piperine was discovered 200 years ago by Danish chemist H.C. Ørsted. As recently as 2024, a fellow Dane from Aarhus University in Denmark found that piperine increases skeletal muscle function in rats. Piperine has a similar effect to placing a larger engine in the Mustang, making it drive faster. My PhD research investigates whether the effects of piperine on muscle function affect the amount of energy that’s used during muscle contraction. In other words, does the faster Mustang burn more fuel?

You might want to hold off on grinding all the black pepper in your kitchen to achieve superhuman strength! Piperine only makes up 5% of black pepper, and you’d have to eat so much black pepper for your muscles to respond that it would be toxic. Even so, piperine is an important tool for physiologists to investigate the general effects of flipping the on/off switch in skeletal muscles. Future efforts to leverage the on/off switch may help improve our lives by addressing loss of physical functioning safely and effectively.