From Sun Gods to Starships: The Surprising History of Light Therapy

Long before the invention of the light bulb, the laser, or the LED, humanity understood a fundamental truth: light is life. It was our first clock, our first compass, and arguably, our first medicine. The story of light therapy is not a modern invention but a tale as old as civilization itself, a thread of wisdom that connects the sun-drenched temples of the Nile to the sterile laboratories of the 20th century, and even to the handheld devices we use in our homes today. It is a surprising history of intuition, accidental discovery, and relentless scientific inquiry, revealing how we learned to bottle a sunbeam and command it to heal.

Children of the Sun: Heliotherapy in the Ancient World

Our journey begins in the ancient world, where the sun was not merely a celestial body but a powerful deity, a giver of warmth, growth, and vitality. The ancient Egyptians, builders of sun-drenched pyramids, practiced a form of solar therapy, exposing the sick to the sun’s rays to treat various ailments. The Greeks, pioneers of rational medicine, formalized this practice. Hippocrates, the father of medicine, meticulously documented the use of sunlight—a practice he termed heliotherapy—for conditions ranging from skin ulcers to jaundice. In the sprawling bathhouses of the Roman Empire, solariums were a common feature, architectural testaments to the belief in the sun’s restorative power. For centuries, humanity bathed in this power with reverent intuition. But it would take the dawn of a new, scientific age—and a determined Danish physician—to dissect its rays and turn a blunt instrument into a surgeon’s scalpel.

The Light of Reason: Niels Finsen and the Dawn of Modern Phototherapy

The story of modern phototherapy begins with Niels Ryberg Finsen. In the late 19th century, this Faroese-Danish physician, himself a sufferer of a condition that left him feeling perpetually cold and tired, became obsessed with the biological effects of light. He theorized that specific components of the light spectrum, not the entire beam, were responsible for its therapeutic effects. Finsen painstakingly developed a system of lenses and filters to isolate and concentrate certain wavelengths. He discovered that the “chemical rays” (what we now call ultraviolet light) had bactericidal properties.

His crowning achievement was the treatment of lupus vulgaris, a disfiguring and then-incurable form of cutaneous tuberculosis. By focusing filtered light from a powerful carbon arc lamp onto patients’ lesions, Finsen achieved remarkable success. This was not folk medicine; it was a controlled, repeatable, scientific procedure. For this groundbreaking work, “in recognition of his contribution to the treatment of diseases, especially lupus vulgaris, with concentrated light radiation,” Niels Finsen was awarded the 1903 Nobel Prize in Physiology or Medicine. He had single-handedly established phototherapy as a legitimate medical science, proving that light, when precisely controlled, could be a powerful therapeutic agent.

A Red Glow in the Void: NASA’s Accidental Contribution to Cellular Healing

Finsen had proven that specific colors of light held medical power. Nearly a century later, this very principle would be rediscovered in the most unlikely of places: hundreds of miles above the Earth, in the quest to conquer space. The story of modern, low-level light therapy is inextricably linked with the National Aeronautics and Space Administration (NASA). In the late 1980s and early 1990s, scientists were grappling with a critical challenge for long-duration spaceflight: how to grow food in space. As part of this research, specifically a project that began in 1993 with the Wisconsin Center for Space Automation and Robotics, scientists experimented with Light Emitting Diodes (LEDs) to stimulate plant growth aboard the Space Shuttle.

They discovered that certain wavelengths of red light were particularly effective at promoting plant cell metabolism. This led to a logical, yet brilliant, leap of thought: if red light could energize plant cells, what could it do for human cells? Astronauts in microgravity experience delayed wound healing. The NASA researchers, funded by a Small Business Innovation Research grant, turned their attention from botany to biology. They began studying the effects of these LEDs on human cells. The results were astonishing. According to NASA’s own publications on the technology transfer, their research indicated that specific LED wavelengths could increase cellular growth by 150% to 200%. This NASA-sponsored research provided powerful validation for a field that had been quietly bubbling under the surface since the 1960s, when a Hungarian physician named Endre Mester had first noticed that low-level red laser light accelerated hair growth and wound healing in mice—a discovery that birthed the field of photobiomodulation.

From Space Stations to Living Rooms: The Democratization of Light

The technology behind this revolution, the LED, had its own quiet history. The first practical visible-spectrum LED was invented in 1962 by Nick Holonyak Jr. at General Electric. For decades, LEDs were low-power indicators on electronic equipment. But as the technology advanced, their power, efficiency, and affordability skyrocketed. NASA’s high-profile research acted as a catalyst. It demonstrated that LEDs, once humble indicator lights, could be powerful, non-invasive medical tools.

What was once confined to high-tech space programs and specialized medical clinics began a journey of “technological descent”—the process by which advanced technology becomes smaller, cheaper, and accessible to the public. Companies began engineering this science into handheld, user-friendly devices. For instance, the development of products like the LightStim for Wrinkles, which incorporates multiple wavelengths of light into a single device, is a direct descendant of this lineage. It represents the final step in the journey: taking the fundamental principle validated by NASA and packaging it for safe, regular use in a domestic setting. This democratization of light therapy placed a tool of cellular rejuvenation, once the stuff of science fiction, directly into the hands of consumers.

The Modern Spectrum: Today’s Landscape of Light-Based Medicine

Today, the legacy of Finsen and the NASA experiments is everywhere. Blue light therapy is a standard treatment for acne and for treating jaundice in newborns. Red and near-infrared light therapies are used by dermatologists, physical therapists, and veterinarians for everything from reducing wrinkles and inflammation to accelerating muscle recovery and healing wounds. The once-esoteric science of phototherapy has become a cornerstone of modern, non-invasive medicine, with an ever-growing body of research supporting its efficacy across a wide spectrum of applications.

Conclusion: A Journey from Awe to Agency

The history of light therapy is a mirror of human progress. It reflects our journey from a state of passive awe before the power of the sun to one of active agency, where we can precisely wield specific wavelengths of light to orchestrate biological processes at the cellular level. It’s a story that starts with a simple, intuitive act—turning one’s face to the sun—and culminates in the ability to hold a device that emits a carefully calibrated spectrum of light, born from Nobel Prize-winning science and space-age research. It reminds us that sometimes, the most futuristic solutions have the most ancient roots.