Red Light Therapy for Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory condition that primarily affects the spine and sacroiliac joints, causing progressive stiffness and pain that can fuse vertebrae over time. Standard treatment relies on NSAIDs, biologics, and physiotherapy. Red light therapy — more precisely, photobiomodulation (PBM) — is increasingly being explored as an adjunct treatment, though the direct evidence for AS specifically remains limited.

This page examines what we know, what we can reasonably infer from related research, and how to approach red light therapy if you have ankylosing spondylitis.

Understanding ankylosing spondylitis

AS is an autoimmune condition driven by chronic systemic inflammation. The hallmark is enthesitis — inflammation where tendons and ligaments attach to bone — particularly along the spine and pelvis. Over time, this inflammation triggers new bone formation, potentially fusing spinal segments and severely restricting mobility.

Key characteristics relevant to red light therapy:

Deep tissue involvement. The affected structures — vertebral joints, sacroiliac joints, entheses — sit beneath multiple tissue layers. Superficial red light (620–660nm) cannot reach them.
Systemic inflammation. AS is not a localised injury. TNF-alpha, IL-17, and other pro-inflammatory cytokines circulate systemically.
Chronic nature. Any therapy would need to be sustained long-term rather than applied as a short course.

What the research says

Direct evidence for AS

As of early 2026, there are no large-scale randomised controlled trials investigating photobiomodulation specifically for ankylosing spondylitis. This is a gap in the literature, not evidence of inefficacy.

A small number of pilot studies and case reports have examined low-level laser therapy (LLLT) — the clinical predecessor to modern LED-based PBM — for AS-related symptoms:

A 2014 study published in Lasers in Medical Science (Altan et al.) investigated LLLT applied to the sacroiliac joints and lumbar spine in 40 AS patients. The treatment group showed statistically significant improvements in pain (VAS scores), morning stiffness duration, and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores compared to sham treatment over a four-week protocol.
Several case series have reported pain reduction and improved spinal mobility following infrared laser application to affected spinal segments, though sample sizes were small and follow-up periods short.

The stronger evidence base lies in conditions that share pathological features with AS:

Inflammatory joint pain. A 2019 Cochrane-style systematic review by Stausholm et al. in BMJ Open analysed 22 RCTs of PBM for inflammatory joint conditions and found moderate evidence for pain reduction and functional improvement, particularly with near-infrared wavelengths at adequate doses (PMID: 31892641).

Chronic back pain. A meta-analysis by Huang et al. (2015) in Arthritis Research & Therapy evaluated LLLT for chronic low back pain across 7 RCTs (394 patients). PBM groups showed significant pain reduction compared to placebo, with effects lasting up to 12 weeks post-treatment (PMID: 26612620).

Rheumatoid arthritis. As a fellow autoimmune inflammatory arthritis, RA shares immune pathways with AS. Multiple RCTs have demonstrated that PBM reduces morning stiffness, pain, and joint swelling in RA. A landmark meta-analysis by Brosseau et al. in the Cochrane Database of Systematic Reviews (2005) found clinically meaningful reductions in morning stiffness duration (PMID: 16235295).

TNF-alpha modulation. Laboratory studies have shown that PBM, particularly at 810nm and 830nm, can reduce TNF-alpha expression in activated immune cells. Given that TNF-alpha is a primary driver of AS (and the target of biologic drugs like adalimumab), this mechanism is directly relevant (Fernandes et al., 2015, Journal of Photochemistry and Photobiology B, PMID: 26000735).

Why near-infrared matters for AS

The spinal structures affected by AS sit deep beneath skin, subcutaneous fat, and paraspinal muscle. Standard red wavelengths (630–660nm) penetrate approximately 2–4mm into tissue — nowhere near deep enough to reach vertebral joints or sacroiliac structures.

Near-infrared (NIR) wavelengths offer substantially greater penetration:

810nm penetrates up to 30–40mm in laboratory models, though effective therapeutic intensity drops significantly beyond 20mm.
850nm shows similar penetration characteristics and has the broadest evidence base for musculoskeletal applications.
940nm penetrates deepest but has weaker absorption by cytochrome c oxidase, the primary chromophore in PBM.

For AS, 830–850nm is likely the most appropriate wavelength range, balancing tissue penetration with mitochondrial absorption. Some protocols combine 660nm (for superficial muscle and soft tissue) with 850nm (for deeper joint structures).

Suggested protocol for AS

The following protocol is extrapolated from the chronic back pain and inflammatory arthritis literature, not from direct AS trials. Discuss with your rheumatologist before starting.

Wavelength

Primary: 830–850nm (near-infrared) for deep tissue penetration to spinal and sacroiliac joints.
Secondary: 660nm (red) for paraspinal muscle tension and superficial inflammation.
Ideal: Combination device delivering both wavelengths simultaneously.

Dosing

Target a fluence of 4–8 J/cm² per treatment area, based on the Stausholm et al. review’s findings for inflammatory joint conditions. This is the therapeutic window — going higher risks an inhibitory biphasic response (the Arndt-Schulz curve).

At a typical treatment distance of 15cm from a panel delivering ~30 mW/cm²:

Treatment time per area = approximately 2–4 minutes
Treat each affected region (lumbar spine, thoracic spine, sacroiliac joints) separately

Frequency

Initial phase (weeks 1–4): Daily sessions, 5–7 times per week
Maintenance phase (week 5 onwards): 3–5 times per week
Ongoing: Indefinitely, as AS is a chronic condition

Device positioning

Treat the posterior spine from behind, with the panel centred on the most symptomatic segments.
Treat sacroiliac joints separately, angling the device toward each SI joint.
If peripheral joints are affected (hips, shoulders), treat those areas individually.

What red light therapy cannot do for AS

Honesty about limitations is important:

It will not halt disease progression. PBM does not suppress the immune system the way biologics or DMARDs do. New bone formation and ankylosis are driven by deep immunological processes that photobiomodulation cannot fully address.
It will not replace medication. If your rheumatologist has prescribed biologics or NSAIDs, PBM should be used alongside these treatments, not instead of them.
Penetration limits are real. Even NIR wavelengths lose most of their intensity by the time they reach deep spinal structures. The dose reaching vertebral joints will be a fraction of the surface dose.

Device recommendations for AS

AS requires a device that covers a large treatment area (the entire spine is potentially affected) and delivers adequate near-infrared output:

Full-body panels (e.g., devices with a treatment area of 90cm or taller) allow you to treat the entire spine in one or two positions.
Half-body panels work but require repositioning to cover the full spinal column.
Handheld devices and wands are impractical — the treatment area is too small and the condition too widespread.
Red light therapy beds offer the most comprehensive coverage, treating the entire posterior surface simultaneously, but the cost is prohibitive for home use.

Prioritise devices with verified NIR output (830–850nm). Many budget panels skew heavily toward 660nm, which is insufficient for the deep tissue targets in AS.

The bottom line

The direct evidence for red light therapy in ankylosing spondylitis is limited to small studies, but the broader PBM literature on inflammatory joint disease, chronic back pain, and TNF-alpha modulation provides a reasonable mechanistic basis for trying it as an adjunct therapy.

If you have AS, PBM is unlikely to be transformative on its own. But as a non-invasive addition to your existing treatment regimen — particularly for managing pain, morning stiffness, and paraspinal muscle tension — the risk-to-benefit ratio is favourable. Use near-infrared wavelengths, dose accurately, and treat consistently. And keep your rheumatologist in the loop.