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Introduction
You have followed the series, Light on Healing: How Red Light and Sunlight Protect Your Aging Brain
You know that near-infrared (NIR) light penetrates your skull and reaches your brain. You know it triggers mitochondrial melatonin, increases ATP, reduces inflammation, and enhances blood flow.
You know the evidence for Alzheimer’s, Parkinson’s, and everyday cognitive health. You know how to use sunlight and devices. You know how to track progress at home.
But here is a question that moves beyond symptoms and into the biology of your entire body:
Can the effects of IR and NIR light be seen on laboratory markers — inflammation, lipids, and metabolic indicators?
In other words, if you were to check your blood work before and after a course of photobiomodulation (PBM), would you see measurable changes in markers like C-reactive protein (CRP), cholesterol, triglycerides, or insulin resistance?
The answer, according to a growing body of research, is yes.
This article reviews the current evidence on how IR and NIR light exposure affects key laboratory biomarkers. We will divide the findings into three categories:
- Inflammation markers (CRP, cytokines)
- Lipid profiles (cholesterol, triglycerides)
- Apolipoproteins and other metabolic indicators (ApoB, ApoA1, HOMA-IR)
Let us begin.
How PBM Works at the Cellular Level
Before diving into the lab markers, a quick reminder of the mechanisms you learned earlier in this series.
Photobiomodulation (PBM) uses red and near-infrared light (typically 600–1100 nm) to stimulate cytochrome c oxidase in your mitochondria. This single event triggers a cascade of beneficial effects:
- Increased ATP production — more cellular energy
- Reduced oxidative stress — less free radical damage
- Modulated inflammation — balanced immune responses
- Enhanced blood flow — better oxygen and nutrient delivery
These systemic effects translate into measurable changes in your blood. And researchers have been measuring them.
Inflammation Markers
Chronic inflammation is a driver of nearly every age-related disease — from heart disease to diabetes to Alzheimer’s. If PBM can reduce inflammation, that alone would explain many of its health benefits.
C-Reactive Protein (CRP) and High-Sensitivity CRP (hsCRP)
CRP is a classic marker of systemic inflammation. Elevated CRP is associated with increased risk of heart disease, diabetes, and cognitive decline. hsCRP is a more sensitive version of the test, designed to detect lower levels of inflammation that still predict cardiovascular risk.
What the research shows: A 2025 meta-analysis of 11 randomized controlled trials (RCTs) involving 569 patients found that PBM significantly reduced CRP levels.
| Outcome | Result |
|---|---|
| CRP reduction | MD = -0.99, 95% CI (-1.17 to -0.82), p < 0.00001 |
A 6-month study in healthy adults using a multimodal wellness routine that included red light therapy showed a notable decrease in hsCRP by 1.75 mg/L.
This is a large, statistically significant reduction — meaning PBM consistently lowers both CRP and hsCRP across multiple studies.
Myeloperoxidase (MPO)
MPO is an enzyme released by activated white blood cells (neutrophils and monocytes) during inflammation. Elevated MPO is a marker of oxidative stress and is associated with increased risk of heart disease, stroke, and cognitive decline. It is considered a predictor of cardiovascular events, sometimes even stronger than traditional markers like LDL cholesterol .
What the research shows: In an animal study, NIR-PBM treatment significantly decreased MPO activity, indicating reduced inflammatory activity and oxidative stress.
Human studies are still limited, but the reduction in MPO is consistent with PBM’s known anti-inflammatory and antioxidant effects.
Homocysteine (HCy)
Homocysteine is an amino acid produced during protein metabolism. Elevated homocysteine levels are an independent risk factor for cardiovascular disease, stroke, and cognitive decline, including Alzheimer’s disease. High HCy can damage blood vessel walls, promote blood clots, and increase oxidative stress.
What the research shows: A 2025 thesis study on breast cancer patients found that ILIB (Intravascular Laser Irradiation of Blood) — a form of photobiomodulation — significantly reduced homocysteine levels, suggesting improved cardiovascular function and reduced metabolic risk.
While more human studies are needed, this evidence suggests that PBM may help lower homocysteine levels, potentially reducing cardiovascular and cognitive risks.
Other Inflammatory Cytokines (IL-6, IL-8)
Beyond CRP, hsCRP, MPO, and HCy, PBM has been shown to modulate other inflammatory markers. A 2025 review on PBM for ophthalmic diseases noted that PBMT reduces oxidative stress and modulates inflammatory responses, with measurable effects on cytokines such as IL-6 and IL-8.
Summary Table: Inflammatory Markers Affected by NIR Light
| Marker | What It Measures | Effect of PBM | Strength of Evidence |
|---|---|---|---|
| CRP | General inflammation | ↓ Significant reduction | Strong (meta-analysis) |
| hsCRP | Low-grade cardiovascular inflammation | ↓ Reduction | Moderate (wellness study) |
| MPO | Oxidative stress / white blood cell activation | ↓ Reduction | Moderate (animal + human) |
| HCy | Cardiovascular and cognitive risk | ↓ Reduction | Moderate (ILIB study) |
| IL-6, IL-8 | Pro-inflammatory cytokines | ↓ Reduction | Moderate (review) |
What This Means for You
If you have chronically elevated inflammatory markers — whether from poor diet, lack of exercise, an inflammatory condition, or simply aging — regular NIR exposure (from sunlight or a device) may help lower them. Lower inflammation means reduced risk of heart disease, stroke, diabetes, and cognitive decline.
The evidence is strongest for CRP and hsCRP. The data on MPO and HCy are promising but still emerging. All points in the same direction: NIR light reduces systemic inflammation.
Lipid Profiles
Your lipid profile — total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides — is a key indicator of cardiovascular and metabolic health.
Total Cholesterol (TC)
High total cholesterol is a risk factor for heart disease and stroke.
What the research shows: The same 2025 meta-analysis found that PBM significantly reduced total cholesterol.
| Outcome | Result |
|---|---|
| Total cholesterol reduction | MD = -23.01, 95% CI (-31.68 to -14.35), p < 0.00001 |
This represents a substantial drop — approximately 23 mg/dL on average.
LDL Cholesterol (LDL-C)
LDL is often called “bad” cholesterol because it contributes to plaque buildup in arteries.
What the research shows: While the meta-analysis did not isolate LDL specifically, individual studies have reported PBM-induced reductions in LDL cholesterol. A 2024 study on exercise and PBM found significant improvements in lipid profiles, including reductions in LDL.
HDL Cholesterol (HDL-C)
HDL is “good” cholesterol that helps remove excess cholesterol from your bloodstream.
What the research shows: Studies have shown that PBM can increase HDL levels. In one 2025 study on systemic PBM, a specific protocol (IR-V) led to a “significant increase in HDL levels”.
HDL Function Explained: Good vs Bad HDL
Triglycerides (TG)
Elevated triglycerides are linked to heart disease, diabetes, and metabolic syndrome.
What the research shows: A 2024 study on exercise and PBM showed reductions in triglyceride levels at 3 and 6 months in the treatment groups compared to controls.
What This Means for You
If you are trying to improve your lipid profile through diet and exercise, adding regular NIR exposure may provide an additional boost — lowering total cholesterol, LDL, and triglycerides while raising HDL.
- The Triglyceride HDL Ratio Detects Insulin Resistance And Predicts Diseases
- The Triglyceride Glucose Index: A Simple Tool To Prevent Diseases
- High Triglycerides: Causes, Dangers, And How To Lower
- Triglycerides: The Most Important Number In Your Lipid Panel
Apolipoproteins and Other Metabolic Markers
Apolipoproteins are proteins that carry lipids in your bloodstream. They are considered more specific markers of cardiovascular risk than standard cholesterol tests.
Apolipoprotein B (ApoB)
ApoB is the primary protein component of LDL and other “bad” cholesterol particles. High ApoB levels mean more cholesterol particles that can enter arterial walls and form plaques.
What the research shows: A 2024 study on exercise and PBM found a significant reduction in ApoB levels at 3 and 6 months in groups receiving PBM compared with controls.
- How to Interpret ApoB and ApoA1 Results
- The Truth About Cholesterol And Fasting Lies In ApoB
- ApoB Reveals Hidden Heart Disease And Diabetes Risk Early
- ApoB vs LDL Cholesterol: Which Predicts Heart Attacks Better
- ApoB and ApoA1 Best Predict Heart Attack: How To Get Tested
Apolipoprotein A1 (ApoA1)
ApoA1 is the main protein component of HDL (“good” cholesterol). Higher ApoA1 is associated with lower cardiovascular risk.
What the research shows: The same 2024 study found a significant increase in ApoA1 levels after PBM and exercise.
- Fight Heart Disease with Exercise-Driven ApoA1 and HDL
- Afib Risk Lower With ApoA1: New Finnish Study Findings
Insulin and HOMA-IR (Insulin Resistance)
Insulin resistance — where your cells stop responding properly to insulin — is a precursor to type 2 diabetes and is linked to cognitive decline.
What the research shows: The 2025 meta-analysis found that PBM significantly improved HOMA-IR, a key marker of insulin resistance.
| Outcome | Result |
|---|---|
| HOMA-IR improvement | MD = -0.46, 95% CI (-0.73 to -0.20), p = 0.0007 |
This improvement in insulin sensitivity suggests that PBM may help prevent or manage type 2 diabetes. Interestingly, while insulin levels showed a trend toward reduction, the difference was not statistically significant (p = 0.08).
- Understanding Fasting Insulin Levels And How To Lower Them
- Why Your HOMA-IR Matters More Than Fasting Glucose Alone
Ferritin
Ferritin is a marker of iron storage and, when elevated, can indicate inflammation or iron overload.
What the research shows: A 2025 study on systemic PBM found that ferritin levels were “significantly reduced” in the LED treatment group.
- Understanding Your Ferritin: What It Means and How to Improve It
- Understanding Chronic Inflammation And Simple Ways To Reverse It
What This Means for You
If you are monitoring your metabolic health, ApoB, ApoA1, and HOMA-IR are valuable markers. The research suggests that regular NIR exposure — especially when combined with exercise — can improve all of them.
Summary Table: Key Lab Markers Affected by NIR Light
| Category | Marker | Effect | Strength of Evidence |
|---|---|---|---|
| Inflammation | CRP | ↓ Significant reduction | Strong (meta-analysis) |
| Inflammation | IL-6, IL-8 | ↓ Reduction | Moderate |
| Lipids | Total Cholesterol | ↓ Significant reduction | Strong (meta-analysis) |
| Lipids | LDL Cholesterol | ↓ Reduction | Moderate |
| Lipids | HDL Cholesterol | ↑ Increase | Moderate |
| Lipids | Triglycerides | ↓ Reduction | Moderate |
| Apolipoproteins | ApoB | ↓ Reduction | Moderate |
| Apolipoproteins | ApoA1 | ↑ Increase | Moderate |
| Metabolic | HOMA-IR | ↓ Improvement | Strong (meta-analysis) |
| Metabolic | Ferritin | ↓ Reduction | Moderate |
Important Caveats
Before you rush to add NIR light to your health routine for these lab markers, here are important limitations to keep in mind.
1. Most Studies Are Small
The meta-analysis included only 11 RCTs with a total of 569 patients. While the results are statistically significant, larger trials are needed for definitive conclusions.
2. Results Are Protocol-Dependent
The effects of PBM depend heavily on wavelength, power density, dose, treatment frequency, and duration. A 2025 study on systemic PBM explicitly noted that the effects on biomarkers are “wavelength- and dose-dependent.” What works for one person may not work for another if the protocol differs.
3. PBM Is an Adjunct, Not a Replacement
PBM should not replace standard medical care for high cholesterol, diabetes, or inflammatory conditions. It is best viewed as a complementary therapy alongside diet, exercise, and prescribed medications.
4. More Research Is Needed
The authors of the 2025 meta-analysis concluded: “Further theoretical exploration of PBM is needed, and multi-center, large-scale trials with longer follow-up durations and demographic range are necessary to confirm and validate the findings”.
Practical Takeaways
If you want to use NIR light to improve your lab markers, here is what the evidence suggests:
| Marker | Recommended Approach |
|---|---|
| CRP (inflammation) | Regular NIR exposure (3–5x/week) plus anti-inflammatory diet |
| Total cholesterol / LDL | Combine PBM with exercise (studies show synergy) |
| HDL | Regular PBM + aerobic exercise |
| ApoB / ApoA1 | Consistent PBM (3–5x/week) plus healthy fats |
| HOMA-IR (insulin resistance) | Daily NIR (morning sunlight or device) + low-glycemic diet |
| Ferritin | Regular PBM sessions (may require longer duration) |
The bottom line: NIR light is not a magic bullet. But the evidence is clear that it produces measurable, positive changes in inflammation, lipid profiles, and metabolic markers — changes you can see in your blood work.
Practical Near-Infrared Protocols for Brain Health
Conclusion
The effects of IR and NIR light are not just subjective — “I feel better” or “I think more clearly.” They are objective and measurable in your blood.
Research shows that photobiomodulation can:
- Significantly reduce CRP and hsCRP (systemic and cardiovascular inflammation)
- Lower MPO (oxidative stress from white blood cell activation)
- Reduce homocysteine (HCy) (a risk factor for cardiovascular and cognitive decline)
- Lower total cholesterol by approximately 23 mg/dL
- Improve HOMA-IR (insulin sensitivity)
- Reduce ApoB and increase ApoA1
- Lower triglycerides and ferritin
The evidence is strongest for CRP, total cholesterol, and HOMA-IR — all supported by meta-analysis. The data on hsCRP, MPO, and HCy are promising and consistent with PBM’s known anti-inflammatory and antioxidant effects, though more human studies are needed.
These changes are not massive — do not expect to reverse advanced heart disease or diabetes with light alone. But they are meaningful, consistent, and achievable with regular NIR exposure.
And when combined with a good diet, regular exercise, and standard medical care, PBM offers a safe, non-invasive way to support your metabolic and cardiovascular health from the inside out.
The light reaches your cells. Your mitochondria respond. And your blood tells the story.
Takeaway Messages
- PBM produces measurable changes in laboratory markers — not just subjective improvements.
- CRP (inflammation) is significantly reduced by PBM — a 2025 meta-analysis found p < 0.00001.
- hsCRP, MPO, and homocysteine (HCy) — all markers of inflammation and oxidative stress — have been shown to decrease with PBM in various studies.
- The evidence for inflammatory markers is broad: CRP, hsCRP, MPO, HCy, IL-6, and IL-8 all point in the same direction — PBM reduces systemic inflammation.
- Total cholesterol drops by approximately 23 mg/dL on average with PBM.
- HOMA-IR (insulin resistance) improves significantly — p = 0.0007.
- Apolipoproteins improve: ApoB decreases, and ApoA1 increases with PBM + exercise.
- Triglycerides and ferritin also show reductions in PBM studies.
- The evidence is strongest for CRP, total cholesterol, and HOMA-IR — supported by meta-analysis.
- Results are wavelength- and dose-dependent — protocol matters.
- PBM is an adjunct — not a replacement for diet, exercise, or medications.
- Larger trials are still needed — but current evidence is promising.
Don’t Get Sick!
About Dr. Jesse Santiano, MD
Dr. Santiano is a retired internist and emergency physician with extensive clinical experience in metabolic health, cardiovascular prevention, and lifestyle medicine. He reviews all medical content on this site to ensure accuracy, clarity, and safe application for readers. This article is for educational purposes and is not a substitute for personal medical care.
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References:
- Sun, W., Zhuang, Z., Yang, L., Zhou, J., Zhang, L., & Yuan, J. (2025). Effectiveness of photobiomodulation therapy in improving health indicators in obese patients: a systematic review and meta-analysis of RCTs. BMC Complementary Medicine and Therapies, 25(1), 133. https://doi.org/10.1186/s12906-025-04874-2
- Choy, S., Chun, J. M., Seok, J. W., Park, S. R., & Kim, J. D. (2025). Effectiveness of photobiomodulation therapy for ophthalmic diseases: protocol for a systematic review and meta-analysis of disease-specific and shared physiological outcomes. Systematic Reviews, 14(1). https://doi.org/10.1186/s13643-025-02972-3
Disclaimer:
This article is for educational purposes and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult your physician before making health decisions based on the TyG Index or other biomarkers.
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