Photobiomodulation to boost immune response

Using red light to modulate T cell response

What if red light is the key to preventing aging in the immune system?

An unsolvable longevity health problem (so far) is that the thymus shrinks and declines with age, decreasing your overall immune response. The thymus is a small organ located just behind the breastbone where T cells are produced and mature.

T cells are a type of white blood cell that fight both infections (bacteria, viruses) and cancerous cells. The decline in response to pathogens means that the flu kills you when you’re old. Similarly, an inability to nip cancerous mutations in the bud means that cancer incidence increases dramatically with aging.

There are multiple types of T cells - some regulate the immune response and protect against autoimmune attacks, while others directly kill off cells that need to be removed.

Photobiomodulation - red light therapy - is one way to help boost T cell function in aging (or at any age). It is exactly what it sounds like: exposure to light in the red wavelengths at a strong intensity. And the clinical trials on it show that it can significantly improve immune function.

Background terminology:
When looking at light therapy, the things to consider include wavelength, intensity, and time of exposure.

Wavelength: The color of the light - wavelength - is important for interacting with cytochrome c in the mitochondria to produce ATP. In the study on mitochondrial ATP production, the researchers used 810nm light. Other studies show that around 610 nm, 760 nm, and 820 nm have an effect.

• Red light: 600-700 nm (visible), penetrates 1-2 cm

• Near-infrared (NIR): 700-1100 nm (invisible)

  • 800-850 nm penetrates 2-4 cm

  • 1064 nm penetrates even deeper

Irradiance (power density): Studies measure this in different ways, which makes it confusing. But irradiance is power (usually mW) divided by area (usually in cm²).

Energy density (Fluence): This is the amount of light energy per unit area times the duration. It comes out to be Joules/cm² in terms of units and is usually in the range of 2-70 J/cm².

U-shaped curve: Some studies show that there is essentially a U-shaped curve in reference to the dose and response. Low levels aren’t going to do anything, too high of levels can be a negative — thus the need for the right wavelength, energy density, and duration. ¹

Clinical trials, immune response:

Let’s take a look at what randomized clinical trials (most with sham control) show for photobiomodulation for immune-related conditions: ²

• 45%reduction in pain and stiffness for rheumatoid arthritis patients (810 nm wavelength, 10 J/cm², 3x weekly for 12 weeks)

• 65% faster wound healing for chronic wounds (660 nm wavelength, 4 J/cm², daily for 4 weeks)

• 40% reduction in asthma exacerbation and improved pulmonary function (904 nm wavelength , 6 J/cm², 2x weekly for 8 weeks)

• 55% improvement in psoriasis inflammation (633 nm wavelength, 12 J/cm², Daily for 8 weeks)

• 30% reduction in relapse rate for MS (670 nm, 5 J/cm², 3x weekly for 16 weeks)

• 30% reduction in ICU length of stay (635nm and 880 nm, 90-second intervals over thighs, legs, arms for 15 minutes)³

Let’s just let that last one sink in for a minute — almost a third less time in the ICU is significant in a lot of ways, including cost. I wonder why every hospital isn’t putting in a red light therapy room.

Mitochondrial health:

Mitochondria are the ‘powerhouse’ of the cells, supplying the ATP needed for most cellular reactions. Researchers in 2024 showed that light at specific wavelengths can enter the mitochondria and excite specific molecules in the electron transport chain to produce ATP directly. It’s not a huge amount (you still need to eat food), but it is a measurable increase. ⁴

In addition to producing ATP, photobiomodulation affects the mitochondrial production of reactive oxygen species (ROS). In cells, ROS needs to be at the right level. Excess ROS causes oxidative stress and can kill the cell, but a low level of ROS is needed as a signaling mechanism to promote antioxidant defense and immune activation. ⁵

Positive T cell changes:

Looking specifically at the changes in T cells, a study involving an animal model of COPD showed that photobiomodulation reduced inflammation in the lungs, reduced mucous, and improved bronchoconstriction. This was in conjunction with positive changes to CD4+ and CD8+ T cells. ⁶

In a mouse model of familial Alzheimer’s, researchers found that photobiomodulation promoted CD4+ T cells and a positive brain immune response.⁷

Rabbit trail: Making people smarter

While I had planned to write only about the immune modulating effects of photobiomodulation, I also wanted to mention that there are a bunch of new studies on photobiomodulation through the skull to improve memory and cognitive function.

• Targeting the prefrontal cortex with a low-level laser on the forehead above the right eyebrow improved memory and cognition for 5 days.⁸

• The military is also interested in photobiomodulation. A study using transcranial photobiomodulation (1,070 nm, 15 minutes) resulted in a decrease in anxiety, stress, and depression while simultaneously improving cognitive performance. ⁹

What to buy?

This is where a great article on photobiomodulation would hold all the answers and tell you the exact best product to buy. I don’t have all the answers.

If you belong to a gym or fitness center, check to see if they have full body red light therapy available. I know people that swear by the full body red lights.

What I ended up buying a few years ago for a muscle injury was from hooga. It was a flexible wrap with 660nm and 850nm wavelengths. I like the flexibility of the wrap format, and at the time it was a moderate price (~$50). But… it looks like hooga no longer makes it. (Here’s something similar for reference.)

Can you help me out?
If you have a red light or photobiomodulation device that you like and recommend, can you post it in the comments? Also important, if you had a red light device that wasn’t high quality or didn’t work for long, I would love the heads up on that as well.

I would also like opinions on whether a whole body setup is worthwhile or if the small flexible wraps are good enough. And if anyone has tried the new helmets for boosting IQ, let me know if it works! The one that I was looking at is around $2K, so I doubt that I will be trying it out any time soon.

1. https://link.springer.com/article/10.1186/s12967-025-07466-3

2. https://pmc.ncbi.nlm.nih.gov/articles/PMC11991943/

3. https://pubmed.ncbi.nlm.nih.gov/38262071/

4. https://www.nature.com/articles/s41598-024-61740-w

5. https://pmc.ncbi.nlm.nih.gov/articles/PMC3141042/

6. https://www.frontiersin.org/journals/medicine/articles/10.3389/fmed.2024.1347517/full

7. https://link.springer.com/article/10.1186/s12974-022-02617-5

8. https://www.frontiersin.org/journals/behavioral-neuroscience/articles/10.3389/fnbeh.2025.1726805/full

9. https://academic.oup.com/milmed/article/190/Supplement_2/456/8256308?login=false