Does Red Light Support the Microbiome?

The gut is a living ecosystem, shaped less by single "fixes" and more by repeatable signals your body learns to trust.

Researchers are now asking whether red and near‑infrared light therapy (called photobiomodulation, or PBM) can change the gut microbiome directly, or whether any microbiome changes are mostly a knock‑on effect of other changes in the body.

What is Photobiomodulation?

Photobiomodulation (PBM) is the use of specific wavelengths of light, often in the red to near‑infrared spectrum, to influence biological processes through light-sensitive molecules in tissues. [1, 2]

Photobiomics: Light and the Microbiome

Photobiomics describes the hypothesis that light exposure can alter the microbiome and metabolome (human metabolism), influencing host physiology through indirect pathways. [3]

The proposed logic is: light affects human metabolism and signalling, those changes reshape the gut environment, and the microbiome shifts in response. [3]

Does Light Relate to the Microbiome?

Across reviews, a core uncertainty persists: are microbiome shifts driven by direct microbial photobiology, or by changes to the human metabolism that secondarily reshape the ecosystem? [3, 6]

1. Direct Microbial Interaction

Some microbes can be light-responsive in certain contexts, but the in vivo gut environment complicates direct light‑microbe effects due to depth, scattering, dose, and intestinal contents. [3]

2. Physiological Effects

A more conservative interpretation is that light influences human physiology first (e.g., immune signalling, mucosal environment), and microbial composition changes because the gastrointestinal function changes. [1, 2]

3. Rhythm Pathways (Nervous System, Circadian, Neuro‑Immune)

The gut is highly sensitive to autonomic balance, motility patterns, hormones, and inflammatory signalling.

Some light-based treatments have been studied for their ability to influence the autonomic nervous system, which helps control "automatic" functions like digestion and heart rate. [4] Research on gut inflammation also shows that the vagus nerve and other nerve-to-immune pathways can play an important role in keeping the gut environment balanced. [5]

In this hypothesis, PBM is less a "gut-targeting tool" and more a rhythm tool that may influence the microbiome downstream.

What the Evidence Says

• Reviews suggest PBM may shift microbiome composition. [6]
• Animal studies link PBM to metabolic and microbiome changes in specific animal models. [7]
• Outcomes likely depend on parameters such as dose, frequency, and tissue context. [8, 9]
• A biphasic response is commonly discussed in PBM literature: more is not always better. [1, 2, 10]

Balancing Energy and Equilibrium

If you want to use PBM as part of a gut-friendly routine, the safest way to think about it is as a steady, supportive habit alongside the basics that help keep your microbiome stable:

• Fibre diversity, hydration, and regular mealtimes
• Measured sessions that prioritise consistency over intensity
• Morning light exposure, to anchor your circadian rhythm:
  • Use BON CHARGE Red Light Therapy Panels in the morning to support wakefulness and circadian alignment.
  • Use BON CHARGE Full Spectrum Light Bulbs throughout the day for day-like circadian-friendly lighting.
• Lower-stimulation light environment at night to reduce melatonin-disrupting wavelengths.
  • Use BON CHARGE Amber Light Bulbs or BON CHARGE Red Light Bulbs in the evening to reduce blue light exposure.
  • Wear BON CHARGE Blue Light Blocking Glasses 2‑3 hours before bed. Also available with prescription lenses.

When you create a more stable internal environment through rhythm, nourishment, and measured signals, your microbiome may shift in response.

BON CHARGE: This content is for general education and is not medical advice. Our products are not intended to diagnose, treat, cure, or prevent any disease. Always follow product instructions and consult a qualified healthcare professional for guidance tailored to you. Individual results may vary.

References

1. de Freitas, L. F. & Hamblin, M. R. Proposed mechanisms of photobiomodulation or low‑level light therapy. IEEE Journal of Selected Topics in Quantum Electronics 22, 7000417 (2016).
2. Dompe, C. et al. Photobiomodulation—Underlying mechanism and clinical applications. Journal of Clinical Medicine 9, 1724 (2020).
3. Liebert, A., Bicknell, B., Johnstone, D. M., Gordon, L. C., Kiat, H. & Hamblin, M. R. Photobiomics: Can light, including photobiomodulation, alter the microbiome? Photobiomodulation, Photomedicine, and Laser Surgery 37, 681–693 (2019).
4. Ali, M. K. et al. Modulation of the autonomic nervous system by one session of spinal low‑level laser therapy in patients with chronic colonic motility dysfunction. Frontiers in Neuroscience 16, 882602 (2022).
5. Bonaz, B. et al. Therapeutic potential of vagus nerve stimulation for inflammatory bowel diseases. Frontiers in Neuroscience 15, 650971 (2021).
6. Jahani‑Sherafat, S., Taghavi, H., Asri, N., Rezaei Tavirani, M., Razzaghi, Z. & Rostami‑Nejad, M. The effectiveness of photobiomodulation therapy (PBMT) in modulation the gut microbiome dysbiosis related diseases. Gastroenterology and Hepatology From Bed to Bench 16, 386–393 (2023).
7. Min, S. H. et al. Duodenal dual‑wavelength photobiomodulation improves hyperglycemia and hepatic parameters with alteration of gut microbiome in a type 2 diabetes animal model. Cells 11, 3490 (2022).
8. Son, Y. et al. Effects of photobiomodulation on multiple health outcomes: an umbrella review of randomized clinical trials. Systematic Reviews (2025).
9. Jiménez‑García, A. M., Zorzo, C., Gutiérrez‑Menéndez, A., Arias, J. L. & Arias, N. Transabdominal photobiomodulation applications: A systematic review and meta‑analysis. Obesity Reviews 26, e13921 (2025).
10. Zein, R., Selting, W. & Hamblin, M. R. Review of light parameters and photobiomodulation efficacy: dive into complexity. Journal of Biomedical Optics 23, 120901 (2018).