Red Light Therapy, Pelvic Inflammation and Endometriosis
Inflammation-related fertility challenges are not uncommon (up to 50% of women) but a lack of understanding of how red light therapy impacts our immune system is. Dr. Ken Woo’s 2025 review, “Therapeutic implications of photobiomodulation application on immune cells,” published in Medical Lasers describes how photobiomodulation can reprogram immune cells and dramatically reduce inflammation in the body. The light is retraining our immune system!
To understand how PBM/red light therapy helps, imagine your immune system as a team of housekeepers, builders, and security guards, all communicating through chemical messages. In a healthy system, they work in together, cleaning up damage, fighting off invaders, and then stepping back to let healing happen. But when you’re dealing with chronic inflammation, these processes fall out of rhythm. PBM’s acts like a smart manager, guiding this team back into balance and making sure it doesn’t overreact to non-threats.
Understanding How PBM Works
PBM uses low-level red or near-infrared light (between 600 - 1,000 nm) to influence your body’s cells without heat or pain. The magic starts deep within mitochondria, the energy factories of our cells. When exposed to PBM’s wavelengths, an important enzyme called cytochrome c oxidase absorbs the light and triggers a cascade of beneficial effects within the body:
1. More cellular energy (ATP): Just as sunlight energizes plants, this light energizes your cells, helping them perform and repair.
2. Balanced oxidative signaling: PBM fine-tunes reactive oxygen species (ROS) - molecules that in small amounts, guide cell repair, but in excess, cause inflammation. Using PBM is like adjusting a thermostat from “too hot” back to “comfortable.”
3. Rebalanced immune signaling: PBM dampens inflammatory pathways like NF-κB and boosts antioxidant pathways such as NRF2, reducing inflammatory messengers (like TNF-α and IL-6) while encouraging soothing molecules (like IL-10 and TGF-β).
Together, these effects shift the immune system from a chronic “attack” mode toward balance and regeneration.
Endometriosis is an immune ‘storm’.
How Red Light Therapy Impacts Specific Immune Cells
Each immune cell has a specific job in inflammation. Think of them as a community working together:
1. Macrophages – The Janitors and Foremen
Macrophages are the cleanup crew that detect damage and start repairs. But sometimes, they overreact and keep scrubbing long after the mess is gone, causing damage to your tissues. PBM helps them calm down and switch from their aggressive M1 type (inflammatory) to their healing M2 type, reducing cytokines like TNF-α and IL-1 while increasing anti-inflammatory messages like IL-10. This shift can be particularly helpful in pelvic inflammation, where excessive scarring disrupts fertility.
2. Neutrophils – The Emergency Responders
Neutrophils rush to the scene first, like EMTs in your tissues. They're vital for defense but can cause collateral damage when they linger too long. PBM reduces their numbers and reduces unnecessary “oxidative bursts,” this helps to decrease tissue swelling and scarring in sensitive regions like the uterus and fallopian tubes.
3. Dendritic Cells – The Messengers
Dendritic cells are like couriers delivering critical information to the adaptive immune system. Red light therapy boosts their efficiency, enhancing antigen presentation and improving communication with T cells. This better coordination helps the immune response stay effective but not amped up, reducing autoimmune-like activity often linked to endometriosis or unexplained infertility.
4. T Lymphocytes – The Strategists
T cells coordinate immune actions, calling the shots for defense and healing. PBM strengthens regulatory T cells (Tregs), which act like peacekeepers, preventing the immune system from attacking its own tissues. It helps balance Th1, Th2, and Th17 cells, important for settling chronic inflammation and supporting a welcoming uterine environment for embryo implantation.
How This Applies to Women’s Reproductive Health
In conditions like endometriosis, pelvic inflammatory disease, or autoimmune-related infertility, the pelvic region can become an inflammatory battlefield. PBM’s multi-pathway action helps by:
· Rebalancing overactive immune responses that damage ovarian or uterine tissue.
· Improving blood flow and mitochondrial energy, aiding repair and oxygenation.
· Boosting regulatory T cells that restore immune tolerance—important so the body recognizes an implanted embryo as safe, not foreign.
PBM is teaching your immune system to heal, not harm.
If you want to geek out on the details of how this all translates into endometriosis - read on.
2025 Immune Studies on Endometriosis
1. The Immune System’s Breakdown in Endometriosis (Hou et al., 2025; Boldu-Fernández et al., 2025)
This study revealed that endometriosis involves both innate and adaptive immune dysfunction. Macrophages in endometriotic lesions show low phagocytic capacity but high production of inflammatory cytokines (IL-6, TNF-α, VEGF, and TGF-β1), which encourage cell growth, new blood vessels, and fibrosis. NK cells become “exhausted,” losing their ability to destroy abnormal tissues. T cells and dendritic cells shift toward an immunosuppressive state, allowing the lesions to persist and pain to intensify.
This immune pattern mirrors the dysregulated pathways PBM can help regulate, such as NF-κB, MAPK, and NRF2, suggesting PBM could recalibrate the overactive inflammatory environment that drives lesion survival. How exciting is this!
2. Immunopathological Insights into Endometriosis (Amidifar et al., 2025)
This molecular review confirmed overactivation of the NF-κB transcription factor in peritoneal macrophages, which drives the release of key inflammatory cytokines (IL-1β, IL-6, TNF-α) and perpetuates a chronic inflammatory state. The authors highlighted oxidative stress and mitochondrial dysfunction as major contributors to this inflammation, precisely the cellular processes that red light therapy is known to rebalance through mitochondrial support and redox signaling balancing.
3. Inflammatory Cytokines as Disease Biomarkers (Bedaiwy et al., 2024)
A diagnostic study found TNF-α, IL-6, and IL-13 in peritoneal fluid were strongly correlated with disease severity and infertility in women with endometriosis. TNF-α was almost 100% sensitive and 89% specific as a diagnostic biomarker, linking it directly to impaired reproductive outcomes. Since PBM downregulates TNF-α and IL-6 through redox-mediated NF-κB inhibition, this provides a biological bridge between PBM’s immune-calming effects and potential fertility improvements.
4. Autoimmunity and Endometriosis Co-Morbidity (Nature, 2025)
A major case-control study demonstrated strong associations between endometriosis and autoimmune disorders, further supporting the immune misfire theory. Overlapping conditions included thyroiditis, lupus, and rheumatoid arthritis, diseases that all share chronic inflammation and regulatory T cell (Treg) deficiency. And whaddaya know - PBM has been shown to enhance Treg activity and rebalance Th1/Th17 dominance, making it a potential tool for modulating these auto-inflammatory cascades.
I thought it would be interesting to see if there were any common denominators in these endo studies and how PBM seems to help (according to Woo’s paper and another 2025 paper on immune modulation)…and there’s a definite pattern.
How PBM impacts the immune system and ovarian gene expression
2025 Connections to Fertility and PBM
Links are increasingly being recognized between endometriosis inflammation and pelvic immune dysfunction and it’s impact on egg quality, implantation, and uterine receptivity. Red light therapy offers a mechanism to address this inflammation via mitochondrial regulation and cytokine rebalancing:
Experts suggest that endometriosis is not simply misplaced uterine tissue, it’s an immune signaling disorder that is created by cellular oxidative stress, mitochondrial imbalance, and a ‘confused’ immune system. Photobiomodulation targets these underlying mechanisms directly, calming the “immune storms” that make endometriosis so difficult to treat.
This evolutionary dance between light, energy, and immunity represents a promising avenue for non-invasive fertility therapies, where modulating inflammation with laser therapy could be a path toward healing and conception.
Tracy
Note on Light Source
When using red light therapy for deep tissues like the uterus or pelvic region, the light source and method of delivery matters. Lasers provide focused, coherent light that penetrates several centimeters into tissue, especially when applied with direct skin contact (or the Fringe wand that puts light IN to your pelvis, directly in contact with your mucosal tissues for greater absorption. Skin contact allows better energy transfer by reducing reflection and scattering, ensuring more photons reach the target. This is why nearly all clinical PBM studies for pain, inflammation, and tissue repair use skin-contact lasers rather than distant light sources. LED panels emit non-coherent, diffuse light that spreads and weakens over distance. They can produce gentle, whole-body or systemic effects when used regularly, but these changes take much longer to appear and remain largely unverified for deep pelvic or reproductive applications. Currently, no peer-reviewed research confirms effective, panel-based PBM results for endometriosis or uterine health, making direct-contact laser application the only evidence-supported method for deep, targeted tissue therapy.
Resources:
https://blog.tracydonegan.org/blog/ultimate-guide-to-choosing-red-light-devices-for-fertility-
