Metformin & Green Light: Two Unexpected Treatments Enter Trials

Metformin & Green Light Therapy: Two Unexpected Treatments Enter Trials

A study published in the journal Pain (May 2026) by Dr. Norman Taylor, MD, PhD at the University of Utah has done two things at once: validated the first reliable animal model for fibromyalgia, and identified two surprising treatment candidates — a diabetes drug and green light — both of which are now entering clinical trials.

The Animal Model Problem

For decades, fibromyalgia research has been hampered by the lack of a reliable animal model. Most existing models were based on acute injury (chemical injections, muscle stress) that don't reflect how fibromyalgia actually develops or behaves in humans — making it difficult to test new treatments with any confidence.

Dr. Taylor's team used a Dahl Salt-Sensitive (Dahl S) rat, a strain that naturally develops widespread pain sensitivity, sleep disruption, and fatigue without any artificial injury — closely mirroring the spontaneous, systemic nature of fibromyalgia in humans. The study validated this model using a standardized scoring system called the Fibromyalgia Analog Model (FAM) index.

The Two Treatments

1. Metformin Metformin is a widely used, inexpensive, and well-tolerated diabetes medication (biguanide class). In the Dahl S rat model, it significantly reduced fibromyalgia-like symptoms. Researchers believe the mechanism involves mTOR pathway inhibition and mitochondrial regulation — both implicated in central sensitization and energy dysfunction in fibromyalgia. A clinical trial in fibromyalgia patients is now underway.

2. Green Light Therapy Exposure to narrow-bandwidth green light (wavelength ~515–530 nm) has been shown in prior animal studies to reduce pain by activating endogenous opioid pathways in the brain without pharmacological intervention. The Dahl S model reproduced these results, and a human trial of green light exposure therapy for fibromyalgia has now been initiated by the Utah team.

Why This Matters

Both treatments are low-risk, low-cost, and already have established safety profiles (metformin from decades of diabetes use; green light from safety studies). If human trials confirm the animal model results, these could become accessible options for fibromyalgia patients relatively quickly — far faster than the typical 10+ year drug development timeline.

The validated animal model itself is equally significant: it gives researchers a reliable tool to screen future drug candidates before expensive human trials, which could accelerate the entire field.