Red light therapy is not a common cause of tiredness. Some people may feel relaxed or sleepy after a session, especially when treatment takes place in the evening, lasts a long time, or follows poor sleep.
Red light therapy, also called photobiomodulation, uses red or near-infrared light. Research on its effects on sleep and alertness remains limited. One randomized study found that a specific near-infrared treatment reduced daytime drowsiness. A review of five randomized trials, published in, found a possible modest improvement in sleep quality, but confidence in that result was limited.
Red Light Therapy and Tiredness at a Glance
| Question | Short answer |
|---|---|
| Is tiredness a typical side effect? | No |
| Can red light therapy make some people sleepy? | Yes, occasionally |
| Does it reliably improve energy? | Not proven |
| Can it affect sleep? | It may, but evidence remains limited |
| What should you do if fatigue persists? | Pause treatment and consider other causes |
Why Might Red Light Therapy Make You Feel Sleepy?
Red light therapy may leave some people feeling sleepy for several reasons:
- Relaxation: Sitting or lying still under a light panel can make you feel relaxed, especially at night.
- Timing: An evening session may overlap with the body's normal preparation for sleep.
- Individual response: People can respond differently to the light's wavelength, intensity, duration and treatment area.
- Existing sleep debt: The tiredness may have been present before the session.
- Device settings: Home devices differ in wavelength, power and recommended exposure time.
Some photobiomodulation research suggests that red or near-infrared light may affect biological processes linked to sleep regulation. The current evidence does not show that ordinary red light therapy consistently causes drowsiness.
Does Red Light Therapy Increase Energy?
Red light therapy is not a proven energy or alertness treatment.
A systematic review of photobiomodulation studies in healthy people found possible benefits for recovery from physical fatigue, but it did not find consistent improvements in strength or functional capacity. The studies used different devices and treatment plans, so their findings may not apply to every red light therapy panel or mask.
Some research has found less daytime drowsiness after near-infrared treatment. That does not mean every red light therapy device will make you feel more awake. The result may depend on the device, dose, timing and treatment area.
What Should You Do If Red Light Therapy Makes You Tired?
If you feel mildly sleepy after a session:
- Do not drive or operate machinery until you feel alert.
- Check the device instructions. Do not extend the session or increase the intensity beyond the recommended limits.
- Try a shorter session only if the instructions allow it.
- Record the session time, duration and treatment area to see whether a pattern develops.
- Avoid using the device immediately before activities that require alertness.
If the tiredness is strong, occurs after every session or lasts for several hours, pause treatment and speak with a healthcare professional. Persistent fatigue can have other causes, including poor sleep, anemia, thyroid disease, medication effects, infection or another medical condition.
Is Tiredness a Recognized Side Effect?
Tiredness is not usually listed as a common short-term side effect of red light therapy.
The American Academy of Dermatology reports that short-term red light therapy appears generally safe. Reported side effects are more often mild skin irritation or pain than tiredness. Long-term effects are less certain. "FDA-cleared" means that a device has been cleared as posing a low risk. It does not prove that the device works for every intended use.
Use extra caution if you take medication that increases light sensitivity or have a light-sensitive condition such as lupus. Follow the manufacturer's instructions for eye protection.
Bottom Line
Red light therapy does not normally make people tired, but occasional sleepiness or relaxation can happen. Photobiomodulation may affect sleep quality in some situations, but it is not a reliable sedative or energy treatment. If fatigue is persistent, severe or new, stop using the device and investigate other possible causes.