NASA and the history of LED photobiomodulation

From space-grown plants to a medical question

NASA’s own retrospective history places the beginning of this strand in plant science. In the late 1980s, the Wisconsin Center for Space Automation and Robotics—supported by NASA’s Marshall Space Flight Center—investigated LEDs as efficient, durable light sources for growing plants in space. Quantum Devices Inc. later received NASA Small Business Innovation Research support for plant-growth hardware; an LED system was used in experiments growing potatoes aboard the Space Shuttle in 1995.[1]

The often-repeated medical origin story includes researchers noticing that abrasions on hands exposed while working with the plant LEDs appeared to heal differently. That observation was anecdotal: it raised a question, but it was not a controlled experiment and should not be retold as proof.

The Whelan and Medical College of Wisconsin work

NASA’s account says the plant-lighting work brought Quantum Devices researcher Ron Ignatius into contact with neurologist Harry Whelan at the Medical College of Wisconsin. From 1995 to 2003, eight NASA SBIR contracts—most funded through Marshall—supported collaborations investigating possible medical uses of LED arrays.[1]

A 2002 NASA Technical Reports Server record describes contract-supported “biostimulation” work using 680, 730 and 880 nm LED systems.[2] This document is useful historical evidence of what the programme studied. As a conference paper covering varied experimental work, it is not equivalent to a large confirmatory human trial.

What the early studies actually contained

Whelan and colleagues’ 2001 publication combined review material with new results from several distinct settings: cell cultures, ischaemic and diabetic rat wound models, and early human observations. The abstract reported increased cell growth in some laboratory experiments, changes in rat wound size under a combined hyperbaric-oxygen and light protocol, observations in US Navy settings, and pain findings in paediatric oral mucositis.[3]

Those are not one experiment. Laboratory growth, animal wound models and human pain reports answer different questions, used different conditions and offer different levels of certainty. The paper did not test modern home panels as a category, and it cannot support a universal “NASA proved red light heals” claim.

A related 2002 study followed 32 paediatric bone-marrow transplant patients. It applied 670 nm light to one side of the mouth and sham treatment to the other, with a historical incidence comparison. The paper reported some favourable observations, but its abstract also reported no significant side-to-side difference in oral-mucositis index or pain scores, and the authors called for more study.[4]

Later controlled human evidence

A 2012 placebo-controlled trial enrolled 80 adult and paediatric stem-cell transplant patients and tested extra-oral 670 ± 10 nm LED treatment. It reported a statistically significant reduction in patient-reported pain for one specified comparison at day 14. Improvements in most other categories and scales were not statistically significant.[5]

This later trial matters because it moved beyond anecdote and some earlier design limitations. Its conclusion is still narrow: a defined protocol, population and outcome in transplant-associated oral mucositis. It does not validate unrelated wellness claims or show that any panel with a similar wavelength will reproduce the result.

A 2025 systematic review found only five eligible LED studies involving 256 participants. Four reported improvements in severity or pain, but the studies were too heterogeneous for meta-analysis; the authors rated the certainty of evidence as low.[6] This is a useful reminder that later research can be promising while important uncertainty remains.

Where NASA’s role ends—and the wider field begins

Research into low-power therapeutic light existed before the NASA collaborations. In 2015, researchers recommended the term photobiomodulation therapy to replace the increasingly awkward “low-level laser/light therapy” terminology.[7] The modern field includes lasers and LEDs, many wavelengths, different doses and a wide range of proposed applications.

Mechanism reviews discuss photon absorption by cellular chromophores, downstream signalling and a biphasic dose response, where more exposure is not necessarily better.[8] These models help frame research; they do not erase the need for condition-specific, controlled human evidence.

What the history supports

• Supported: NASA funded plant-growth LED technology and later SBIR-supported investigation of medical LED applications.
• Supported: Whelan-era researchers reported laboratory, animal and early human findings that helped motivate further work.
• Not supported: that NASA invented light therapy, used these medical devices routinely in space, or proved consumer red-light panels effective for broad wellness claims.
• Still required: application-specific evidence, a defined dose and critical reading of study design and limitations.

Next: what photobiomodulation means today →