How Red Light Therapy Affects Cortisol Levels and the Body's Stress Response

Created on April 19, 2026 Written by BestQool R&D Team:

Introduction

Stress has become such a normal part of our daily life that most people do not even recognize when their bodies are stuck in a constant state of tension. At the center of this response is cortisol, which is the body’s primary stress hormone.

Cortisol plays a key role in regulating energy and sleep and maintaining overall balance. When cortisol levels remain elevated for too long, they can quietly disrupt multiple systems in the body. Red light therapy is emerging as a potential supportive tool to restore cortisol balance and manage stress.

In this article, we will explore how red light therapy influences cortisol and its potential role in supporting your body’s ability to recover from ongoing stress.

Nowadays, stress is seen as a normal part of life. However, many people don’t realize how deeply it affects their health by stimulating the secretion of the stress hormone, cortisol.

However, the problem is not cortisol itself. Cortisol is designed to help us stay alert, react to challenges, and maintain energy balance. The problems arise when the levels of this hormone stay elevated for too long. Read the clinical study on the role of cortisol in stress response. [1]

Persistently elevated levels of cortisol can contribute to a wide range of issues, such as:

• Poor sleep and insomnia
• Weight gain (especially around the abdomen)
• Chronic fatigue
• Anxiety and mood swings
• Hormone imbalances
• Weak immune function
• Chronic inflammation

These consequences develop over a period of time when cortisol does not return to its baseline, even after the period of stress is over. As a result, many people live in a state of “low-grade stress” without realizing it. Research on the systemic impact of chronic cortisol elevation. [2]

This marks the importance of supporting your body’s ability to regulate cortisol levels naturally for long-term health and wellness.

Light is one of the most powerful signals our body receives. It regulates the body’s internal clock, balances hormone rhythms, and regulates sleep-wake cycles.

Cortisol is closely tied to these light-driven biological rhythms.

Our body follows a 24-hour cycle called the circadian rhythm, which controls when certain hormones, including cortisol, rise and fall. The secretion of cortisol typically peaks in the morning to help you wake up and declines gradually throughout the day.

Natural sunlight plays a major role in maintaining this cortisol rhythm. Exposure of the eyes and skin to sunlight sends signals to the brain, regulating cortisol production.

Red light therapy (RLT) has the potential to interact with this system in a more subtle way. It is believed to work by promoting cellular function, thereby creating a more balanced stress response.

Early research on red light therapy and cortisol has suggested a potential link between light exposure and reduced stress markers. The findings suggest that RLT may influence certain underlying mechanisms that support hormonal balance.

For example, some studies have shown that exposure to red and near-infrared light may help lower oxidative stress and inflammation, both of which are linked to elevated cortisol levels. Some studies have also reported improvements in sleep quality and recovery following red light therapy. Clinical review of the diverse benefits of red light therapy. [3]

These findings suggest that RLT might act as a supportive tool to help your body return to a more balanced state, especially when combined with other healthy habits.

The nervous system plays a vital role in how your body handles stress. Cortisol levels remain elevated when you are constantly in a “fight or flight” state.

Research suggests that red light therapy might help promote a shift toward the parasympathetic nervous system, often referred to as the “rest and repair” mode. RLT involves the use of specific wavelengths of red and near-infrared light, typically between 630 nm and 850 nm, which can penetrate deeper into affected tissues, stimulating mitochondria.

Mitochondria are the energy-producing structures inside cells. RLT, by stimulating mitochondria, increases energy production and thus supports cellular function, including healing. Study on the role of red light in cellular energy production. [4]

These benefits of red light can help you feel calmer by supporting healing, reducing tension, and promoting a greater sense of ease. This effect aligns with the idea that cortisol levels naturally begin to reduce when the body feels safe and supported. Learn how red light therapy supports biological healing. [5]

Cortisol secretion follows a daily rhythm. This is why the timing when you use RLT matters so that you can see the desired results based on your specific concerns.

For example, using red light therapy in the morning may support energy levels and reinforce your natural wake cycle. It can complement exposure to natural light.

Evening sessions, on the other hand, are often recommended for relaxation. Red light therapy in the evening can reduce tension, help you unwind, and prepare you for sleep, thereby supporting a natural decline in cortisol at night.

So, some people benefit from using RLT in the morning, others from evening sessions, and some from a combination of both. You can experiment and observe how your body responds to determine what works for you.

Red light therapy works best when used as part of a broader strategy that includes healthy lifestyle habits. Red light therapy can complement these habits by supporting recovery, improving sleep quality, and helping the body manage inflammation.

For example, practices such as quality sleep and stress-management techniques like breathing exercises or mindfulness can be effective for regulating cortisol.

Managing Cortisol Is a Long Game, and Red Light Therapy Can Be Part of It

In today’s fast-paced world, eliminating stress completely isn’t realistic. However, it is possible to improve how your body responds to it. Restoration of balance requires patience and consistency.

Supportive tools like red light therapy can improve long-term cortisol balance when used consistently. RLT offers a gentle, non-invasive way to regulate the body’s natural stress response. It may help you feel more resilient and better equipped to handle daily stress.

Click on this link to learn more about red light therapy and its benefits for your overall health and wellness.

References:

1. Tafur, J., & Mills, P. J. (2008). Low-intensity light therapy: exploring the role of redox mechanisms. Photomedicine and laser surgery.
2. Kaur J, Gandhi J, Sharma S. Physiology, Cortisol. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2026 Jan.
3. Knezevic, E., et al. (2023). The Role of Cortisol in Chronic Stress and Psychological Disorders. Cells.
4. Hamblin M. R. (2017). Mechanisms and applications of the anti-inflammatory effects of photobiomodulation. AIMS biophysics.
5. Kuppa, S. S., et al. (2025). Red-light LED therapy promotes wound regeneration and reducing IL-1β. Lasers in medical science.