Study shows red light improves functional brain networks and working memory in healthy older adults

Red light therapy is often discussed in relation to pain, inflammation, and recovery. But researchers are also studying another exciting area: brain health. A 2025 human study (Yang et al., 2025) published in NeuroImage looked at whether transcranial red light (called photobiomodulation), or near-infrared light applied to the head, could improve working memory in healthy older adults. For many people interested in aging well, cognitive health, and maintaining independence, this is an area worth paying attention to.

What the Study Looked At

The study included 55 healthy older adults between the ages of 55 and 79. Each participant received both an active transcranial photobiomodulation treatment and a sham treatment, separated by a washout period of more than 30 days. This crossover design allowed researchers to compare each person’s response to real treatment versus placebo-style treatment.

The active treatment used a 1064 nm near-infrared laser applied to the left forehead for 12 minutes, targeting the left prefrontal cortex. This area of the brain is closely involved in attention, executive function, and working memory.

This is important because working memory is one of the cognitive skills we rely on every day. It helps us hold and use information in the moment, whether we’re following instructions, making decisions, remembering a number, or keeping track of a conversation.

After treatment, participants completed a working memory task called an n-back test. In simple terms, a number appears on a screen, and the participant has to decide whether it matches a number shown earlier.

In a 1-back task, they compare the current number to the one immediately before it. In a 2-back task, they compare it to the number from two steps back. In a 3-back task, they have to remember and compare the number from three steps back. The 3-back version is the most demanding. It requires focus, mental flexibility, and short-term memory, which makes it a useful way to test working memory under higher cognitive load.

What the Researchers Found

After the active near-infrared light treatment, participants performed better on the 3-back task. They were more accurate and responded faster compared with the sham treatment. The easier 1-back and 2-back tasks did not show the same meaningful improvement, suggesting the effect was most noticeable when the brain had to work harder.

The researchers also used functional near-infrared spectroscopy, called fNIRS, to observe changes in brain network activity. After the active treatment, the brain showed increased functional connectivity and improved network efficiency, especially in frontoparietal areas. These regions are involved in attention, working memory, and higher-level thinking.

In plain language: The brain appeared to communicate more efficiently after red light treatment. This is one of the more interesting parts of the study. It suggests that near-infrared light therapy may not simply affect one isolated area of the brain. Instead, it may influence broader brain network communication.

Why Might Light Affect Brain Function?

The proposed mechanism is familiar to photobiomodulation research. Near-infrared light interacts with cytochrome c oxidase, an enzyme found in the mitochondria. Mitochondria are responsible for producing cellular energy, or ATP. By supporting mitochondrial activity, photobiomodulation can help cells function more effectively.

In the brain, this may relate to oxygenation, energy metabolism, and neuronal communication. That matters because the brain is energy-hungry. Supporting cellular energy can help to explain why researchers are studying red light therapy for cognition, working memory, and healthy aging.

We’re Paying Attention

At RegenClinic, we follow studies like this because they help show where the science of red light therapy is going. Photobiomodulation is being studied across many areas of health, including pain, inflammation, recovery, skin health, wound healing, and now brain health. This study adds to a growing body of research suggesting that red and near-infrared light may support the body at a cellular level, including the brain.

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If you’re interested in cognitive health, aging well, or exploring transcranial red light therapy, we’re happy to talk through what is available, what the research currently says, and whether it may be appropriate for you.

Call or text us at 250-208-4218
Email: hello@regenclinic.ca