Seasonal affective disorder (SAD) is more than the “winter blues.” It’s a real mood disorder linked to reduced light exposure that can disrupt your sleep, energy, and internal clock. Bright light therapy has long been the go-to treatment, but newer options like red light therapy are raising questions. Here’s what the research actually shows.
Bright Light Therapy Is Still the Gold Standard for SAD
Traditional light therapy remains the most evidence-backed treatment for SAD. It typically involves exposure to bright white light—around 10,000 lux—used in the morning to mimic natural sunlight.
“Traditional light therapy using sunlight, natural white lighting, or shorter-wavelength blue light works well to combat SAD when used in the earlier part of the day,” says Dr. Raleigh Duncan, founder of Clearlight and widely-recognized infrared sauna technology pioneer.
Research supports that approach. A 2019 meta-analysis shows consistent improvements in mood and circadian alignment with morning light exposure. Studies also suggest that short-wavelength blue light can be just as effective as white light for SAD treatment.
Where Red Light Therapy Fits—and Where It Doesn’t
Red light therapy isn’t a replacement for bright light therapy, but it can work alongside it. “Red light therapy has been shown to improve mood, enhance circadian rhythm, and help mitigate the effects of SAD when used later in the day,” says Dr. Duncan.
Red light works at the cellular level through a process called photobiomodulation, which helps boost mitochondrial energy, improve circulation, and support healthier sleep. Research has linked these effects to improvements in sleep quality and depressive symptoms.
In one randomized trial of female basketball players, red light exposure improved sleep quality and physical performance—suggesting added benefits for recovery, energy, and mood.
Nervous System Regulation Matters, Too
Light isn’t the only factor. “Seasonal depression is not only a mood issue—it’s a chronic stress physiology problem,” says Dr. Jay Wiles, who studies nervous-system regulation.
Tools like the Ohm Resonance Lamp aim to support regulation through timed breathing and sensory cues rather than brightness alone. “Instead of asking people to think their way out of stress, the lamp helps the body physically downshift,” Wiles explains.
Nutrition and Mood During the Dark Months
Light exposure also affects nutrition-related hormones. “Decreased sunlight impacts melatonin, serotonin, and vitamin D production,” says Dr. Jaz Robbins, clinical professor of psychology at Pepperdine University.
Low vitamin D levels have been linked to reduced serotonin activity and mood dysregulation. Robbins recommends prioritizing vitamin D–rich foods, omega-3s, and B vitamins, while avoiding blood-sugar spikes that can worsen mood and energy.
What You Can Do Today to Feel Better This Winter
Shorter days and longer nights can quietly throw your internal clock off balance—but a few well-timed light, sleep, and nutrition habits can help reset your rhythm and protect your mood when daylight is scarce.
- Use bright light therapy in the morning to anchor your circadian rhythm. A high-output option like the Carex Day-Light Elite Light Therapy Lamp delivers clinical-grade brightness to signal “daytime” to your brain and support mood and energy when daylight is limited.
- Consider red light therapy in the evening (10–15 minutes) to support sleep and recovery. An at-home option like Clearlight’s Core Red Light delivers targeted red and near-infrared wavelengths that help your body wind down and prepare for deeper, more restorative sleep.
- Protect sleep first. Dim lights at night and limit screens. If you’re on a newer device like the iPhone 17, turn on Night Shift and Focus modes to reduce blue light and make late-night screen time easier on your sleep.
- Eat for mood. Choose omega-3s, B vitamins, vitamin D–rich foods—think salmon or sardines, eggs, leafy greens, mushrooms, and fortified dairy—to support brain chemistry, steady energy, and more stable mood during darker months.
- Lift for mood:Strength training is a proven mood booster—helping reduce depression, improve sleep, and build stress resilience when energy and daylight are low, according to research.
- Be consistent. Daily habits matter more than intensity.
Bottom line: Bright light therapy treats SAD directly. Red light therapy supports sleep, energy, and recovery. Used together, at the right times, they may help you feel more like yourself again, even in the darkest months.
