What This Trial Looked At
Diabetic peripheral neuropathy is one of the most disabling long-term complications of type 2 diabetes. Years of elevated blood glucose damage the small nerves that supply the feet and hands, producing burning pain, numbness, loss of protective sensation, and an elevated risk of foot ulcers and amputation. Standard pharmacological treatments — gabapentinoids, antidepressants, opioids — help some patients but leave many with inadequate pain relief and significant side effects. A 2025 single-blinded randomised controlled trial in 200 patients tested whether photobiomodulation therapy could offer a non-pharmacological alternative or adjunct.
The trial randomised 200 adults with type 2 diabetes and clinically diagnosed peripheral neuropathy into two equal groups. The intervention arm received ten days of low-level helium-neon laser therapy at 632.8 nm (3.1 J/cm² dose, nine-minute sessions applied to both the dorsal and plantar surfaces of the foot). The control arm received an identical-looking sham laser treatment. Outcomes were assessed at baseline and four weeks after the end of treatment, covering pain intensity, neuropathy symptoms, protective foot sensation, and validated quality-of-life measures, alongside a panel of neuron-specific biomarkers.
What They Found
The photobiomodulation group showed significant improvements compared with sham across the patient-reported outcomes that matter most in everyday life. Neuropathic pain scores decreased meaningfully. Neuropathy symptom severity dropped. Protective foot sensation — the touch and pressure perception that warns patients of injury before it becomes a wound — improved measurably. Quality of life scores moved in the same favourable direction.
The neuron-specific biomarker panel pointed the same way as the clinical measures. The signal across pain, sensation, function, and biological markers was consistent rather than scattered, which is the kind of internal coherence that strengthens confidence in a single-trial result.
What This Means in Context
This is a recent, reasonably sized randomised controlled trial — 200 patients is large by the standards of the photobiomodulation neuropathy literature, where most prior work was based on smaller pilots. The sham-controlled design with blinded outcome assessment substantially reduces the risk that improvements were driven by expectation or attention effects.
The four-week follow-up window means the trial speaks more directly to short-term symptom relief than to whether benefits persist over months or years — that question is left to longer follow-up studies. The protocol used was a clinical one (ten daily sessions of low-level laser applied by a trained operator), so the trial does not by itself establish that any specific at-home device or schedule will reproduce the same outcomes.
What It Means for You
If you live with diabetic peripheral neuropathy and conventional pain management has only partly helped, this trial adds substantial recent evidence that consistent photobiomodulation may meaningfully reduce neuropathic pain and improve foot sensation. Photobiomodulation is best used alongside the foundations of diabetic care — blood-glucose control, foot inspection, podiatric review — rather than as a replacement. Talk to the clinician helping you manage your diabetes before adding any new approach.
Citation: Authors et al. (2025). A single blinded randomized controlled trial assessing the effect of photobiomodulation therapy on neuron specific biomarkers in type II diabetes mellitus patients with peripheral neuropathy. PubMed
