Light Therapy 101: A January Survival Tool

Light therapy (also called bright light treatment or phototherapy) involves controlled exposure to an artificial light source that mimics certain characteristics of natural sunlight. The most common form uses a light therapy box or light box that emits bright white light at a specific light intensity, typically 10,000 lux.

Unlike ordinary indoor lighting, which usually ranges from 100–500 lux, these light therapy lamps deliver a concentrated dose of light designed to influence the brain’s mood-regulating and circadian systems.

Importantly, modern commercially available phototherapy devices are designed to filter out harmful ultraviolet light (including UVA light, UVB, and ultraviolet radiation), making them generally safe when used properly.

During winter, reduced light exposure—especially in the morning—can disrupt the body’s circadian rhythm, the internal clock that governs sleep, hormone release, metabolism, and mood.

Less direct sunlight means:

• Delayed melatonin suppression
  

• Reduced serotonin signaling
  

• Altered cortisol rhythms
  

• Increased fatigue, cravings, and weight gain
  
  

These biological changes are strongly associated with seasonal affective disorder (SAD), a subtype of mood disorders characterized by recurring winter depression.

Multiple controlled trials, placebo controlled trials, and systematic reviews—including research published in the New England Journal of Medicine—show that bright light therapy leads to a significant reduction in depressive symptoms, particularly for winter depression.

Light therapy is considered a first-line, effective treatment for SAD. Clinical trials consistently demonstrate improvements in mood, energy, sleep, and concentration.

Evidence suggests light therapy may also benefit nonseasonal depression, major depression, and non seasonal depression, especially as an adjunct to antidepressant medication or other treatments.

Light therapy may help patients suffering from bipolar depression, but timing and intensity must be carefully managed under guidance from a mental health professional to avoid triggering mania.

Some studies show beneficial effects of bright light therapy for perinatal depression, offering a non-drug option during pregnancy and postpartum.

By reinforcing circadian alignment, light therapy may improve insomnia, delayed sleep phase disorder, and other sleep disorders.

Research is ongoing into potential benefits for Alzheimer’s disease (the most common form of dementia that increases with age), mood disorders, wound healing, and even inflammation regulation. Early findings suggest light therapy may reduce inflammation and support neurological health, though this remains an active area of investigation.

Light therapy works through the eyes—but not through vision.

Specialized retinal cells detect emitted light and signal the brain’s suprachiasmatic nucleus (SCN), the master circadian clock. This process:

• Suppresses melatonin earlier in the day
  

• Increases alertness
  

• Improves serotonin signaling
  

• Resets sleep–wake timing
  
  

This mechanism explains why starting light therapy in the morning is most effective.

The antidepressant effect appears comparable to medication in some studies, particularly for SAD, without many of the systemic side effects associated with drugs.

When selecting a light therapy box, look for these physical characteristics:

• 10,000 lux output at a safe distance
  

• Broad-spectrum bright white light therapy
  

• No ultraviolet radiation
  

• Clinically tested or FDA-cleared
  

• Designed for at home devices use
  
  

Avoid:

• Tanning beds (high UV exposure, skin cancer risk)
  

• Devices emitting excessive blue light without filtering
  

• Unregulated light devices with unclear intensity ratings
  
  

Some newer tools include dawn simulation lamps, which gradually increase light in the morning, and near infrared light or red light devices—though these serve different therapeutic purposes and are not equivalent to bright light treatment for depression.

Starting light therapy doesn’t require hours of exposure.

Typical guidelines:

• Use for 20–30 minutes daily
  

• Morning use (within 1 hour of waking)
  

• Sit about 16–24 inches from the light therapy box
  

• Do not stare directly into the light
  
  

Light therapy is generally safe, but mild adverse effects can include:

• Headache
  

• Eye strain
  

• Nausea
  

• Increased light sensitivity
  
  

People with medical conditions, eye disease, skin conditions, or heightened light sensitivity should consult a mental health professional or physician before use.

Light therapy should not include ultraviolet light, UVB phototherapy, or UVA light, which are used in office treatments for certain skin conditions and carry different risk profiles, including skin cancer.

A critical review of multiple clinical trials and controlled trials shows:

• Faster symptom improvement than placebo
  

• Comparable outcomes to antidepressants for SAD
  

• Additive benefits when combined with other treatments
  
  

Evidence supporting light therapy continues to grow, with research spanning psychiatry, sleep medicine, and environmental therapeutics.

Light therapy isn’t a cure-all—but it’s a powerful tool when combined with:

• Consistent sleep timing
  

• Morning outdoor light exposure when possible
  

• Regular movement
  

• Nutrient-dense nutrition
  

• Stress regulation
  
  

At Tally Health, we view light therapy as one piece of a broader strategy to support mental health, biological rhythms, and long-term resilience—especially during challenging seasonal transitions.

January doesn’t have to feel like a biological uphill climb.

For many people—especially those experiencing seasonal depression—bright light therapy offers a safe, evidence-backed way to restore circadian balance, improve mood, and support mental well-being during winter’s darkest weeks.

As always, if you’re experiencing persistent or severe depression symptoms, work with a qualified mental health professional to determine the best personalized treatment plan.

Light matters. And in winter, it may matter more than you think.

Light therapy helps reset your circadian rhythm. Vitality supports what happens deeper—inside your cells.

Tally’s signature longevity supplement is formulated with science-backed ingredients to support longevity over time—especially when stress, low light, and winter routines take a toll.

Your healthiest year isn’t built overnight. It’s built daily—starting at the cellular level.