Can Red Light Therapy Cause Fatigue?

Most people use red light therapy to support energy production within cells, so it may seem surprising that some users report feeling temporarily tired after a session. While fatigue is not a common side effect, it can occasionally occur during the early stages of treatment.

One explanation is that red light therapy stimulates mitochondrial activity, which increases cellular energy production. This process may encourage the body to initiate repair and recovery mechanisms. During these biological processes, some individuals may experience a temporary feeling of relaxation or fatigue.

Another possibility is that the treatment itself can be very calming. Many sessions involve sitting or lying still in a quiet environment for several minutes while the device emits warm light. This relaxing atmosphere can sometimes lead to a sense of drowsiness or physical relaxation similar to what people feel after a massage or meditation session.

Fatigue may also be influenced by external factors such as sleep quality, hydration levels, or overall health. Individuals who begin therapy while already feeling tired may simply become more aware of their fatigue during the session.

In most cases, this effect is temporary and disappears as the body becomes accustomed to the therapy. Many users actually report improved energy levels after several weeks of consistent treatment.

If fatigue continues or becomes bothersome, reducing session duration or frequency may help restore balance.