Red light therapy works best on a clean, dry face, done 3 to 5 times per week in sessions of 10 to 20 minutes. But “when” covers more than just frequency. Most people searching this want to know the best time of day, where it fits in a skincare routine, and how long before results show up. Here’s what the evidence supports.
Morning or Evening Sessions
Either works for skin benefits, but morning sessions may offer a slight edge if you’re also looking to improve energy and mood. Light exposure in the morning helps shift your body’s internal clock earlier, which supports alertness and can reduce symptoms of seasonal mood changes. A controlled study found that morning light was significantly better than evening light at reducing depressive symptoms in people with winter depression, largely by correcting a delayed melatonin cycle.
For purely cosmetic goals like fine lines or skin tone, the time of day doesn’t meaningfully change how your skin cells respond to the light. Pick whatever time you’ll actually stick with. Consistency matters far more than the hour on the clock.
Where It Fits in Your Skincare Routine
Use red light therapy on freshly washed, bare skin. No makeup, no sunscreen, no serums. Products sitting on the surface of your skin can scatter or block the light wavelengths before they reach the deeper layers where they do their work. Heavy or opaque formulas, especially anything oil-based, are the biggest offenders.
The simplest routine looks like this: wash your face, pat it dry, do your red light session, then apply your serums and moisturizer afterward. Some users report better results when they apply a green tea extract (as a toner or serum) before treatment, and a small number of studies support the idea that green tea’s antioxidant compounds may enhance the therapy’s effects on skin cells. But this is the one exception to the clean-skin rule.
There’s also a practical benefit to doing the light session first. Red light therapy can temporarily increase blood flow to the skin’s surface, which may improve absorption of the products you apply afterward.
What to Avoid Before a Session
Skip any active ingredients before treatment. Retinol, vitamin C serums, chemical exfoliants, and other strong actives can increase your skin’s sensitivity to light. Layering these under a red light device risks irritation, especially if you’re combining multiple actives in one routine. Keep it simple: rotate your strongest products to a different time of day or use them on your off days from light therapy.
Oxidized vitamin C is a particular concern. If your vitamin C serum has turned dark yellow or brown, it’s broken down and can irritate skin rather than help it. Toss it regardless, but definitely don’t pair it with light therapy.
Session Length and Frequency
For anti-aging, acne prevention, or general skin rejuvenation, aim for 3 to 5 sessions per week at 10 to 20 minutes per session. The right duration depends on your device’s power output. Panel-style devices with higher irradiance can deliver an effective dose in 10 minutes, while lower-powered LED masks may need the full 20.
More isn’t better. Your skin cells can only absorb a certain amount of light energy before additional exposure stops producing benefits. Doubling your session time won’t double your results, and overdoing it can cause mild irritation or redness, which defeats the purpose.
If you’re just starting out, begin at the lower end: 10 minutes, 3 times per week. After two weeks, increase to longer or more frequent sessions if your skin tolerates it well.
How Far to Position the Device
Hold or position your device 6 to 12 inches from your face. For skin-specific goals like improving texture or reducing fine lines, 8 to 12 inches is the sweet spot. Getting too close concentrates the energy output and can cause skin irritation or uncomfortable heat, especially around thinner skin near the eyes and forehead.
If your device has a fan or feels warm during use, that’s normal, but warmth that becomes uncomfortable means you’re too close. Move back an inch or two and see if the sensation eases.
Eye Protection During Facial Treatments
Red light at therapeutic wavelengths isn’t considered dangerous to the eyes in the same way UV light is, but the brightness can be intense. At minimum, keep your eyes closed throughout the session. If you have sensitive eyes or find the brightness bothersome even with eyes shut, wear protective goggles designed to block the specific wavelengths your device emits. Most reputable devices include a pair in the box.
Near-infrared wavelengths, which many facial devices include alongside red light, are invisible to the eye but still carry energy. Closing your eyes reduces exposure significantly, and the skin of your eyelids can still receive some benefit from the near-infrared portion of the treatment.
How Long Before You See Results
Don’t expect overnight changes. Most people begin noticing subtle improvements in skin texture and tone after 4 to 6 weeks of consistent use at 3 to 5 sessions per week. More significant changes, like reduced fine lines or fading of post-acne marks, typically take 8 to 12 weeks. The process works by stimulating your skin’s own collagen production and cellular repair, which takes time to become visible on the surface.
If you stop using the device, the benefits gradually fade over several weeks, similar to how your skin returns to baseline after stopping any active skincare product. Most people who see results treat it as an ongoing part of their routine rather than a short-term fix. After the initial ramp-up period, dropping to 2 or 3 maintenance sessions per week is a common approach.