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What Is Seasonal Affective Disorder (SAD)?

December 29, 2025

Understanding the Winter Blues—and How Light Therapy Can Help

If your mood takes a noticeable dip during the colder, darker months, you’re not alone. Many people experience low energy, sadness, and trouble concentrating in the fall and winter. These symptoms could be more than just “the winter blues”—they could be signs of Seasonal Affective Disorder, or SAD.

What Is Seasonal Affective Disorder?

Seasonal Affective Disorder is a form of depression that occurs at certain times of the year, most commonly in late fall or winter. It’s thought to be triggered by the shorter days and lack of sunlight, which can disrupt your body’s natural rhythms and brain chemistry.

Common Symptoms of SAD:

  • Persistent low mood or sadness
  • Loss of interest in activities you usually enjoy
  • Low energy or fatigue
  • Difficulty concentrating
  • Sleeping more than usual
  • Weight gain or carbohydrate cravings
  • Feeling hopeless or withdrawn

These symptoms usually start in fall or early winter and resolve in spring or early summer, when daylight increases.

What Causes SAD?

The exact cause of Seasonal Affective Disorder isn’t fully understood, but several key factors are believed to contribute:

  1. Lack of Sunlight

Less sunlight can disrupt your internal body clock (circadian rhythm), leading to feelings of depression.

  1. Serotonin Deficiency

Sunlight helps regulate serotonin, a brain chemical that affects mood. Less light can reduce serotonin levels, contributing to depressive symptoms.

  1. Melatonin Imbalance

Darker days increase melatonin production, which may cause excessive sleepiness and lower energy levels.

How Is SAD Treated?

Effective treatments for Seasonal Affective Disorder include:

  • Bright light therapy
  • Talk therapy (CBT)
  • Lifestyle changes such as exercise and outdoor activity
  • Medication, in some cases

Among these, light therapy is one of the most proven and accessible treatments.

Light Therapy: A Bright Solution for SAD

Light therapy works by mimicking natural sunlight. Daily exposure to bright light—typically 10,000 lux for 20–30 minutes in the morning—can reset your internal clock, boost serotonin levels, and help you feel more awake, positive, and balanced.

SAD Solutions from Phothera: Light Therapy You Can Trust

At Phothera, we understand how deeply Seasonal Affective Disorder can affect your life. That’s why we offer SAD Solutions light therapy boxes—trusted, medical-grade devices designed to safely and effectively treat symptoms of SAD.

Why Choose SAD Solutions by Phothera?

  • Clinically proven 10,000 lux output at a comfortable distance
  • UV-free and glare-free light
  • Convenient, portable design for home or office
  • Safe for daily use with no prescription required
  • Designed to support circadian rhythm regulation and mood improvement

With regular use, many people begin to notice an improvement in energy, focus, and mood in just one to two weeks.

How to Use a SAD Light Therapy Device

Using a SAD Solutions light is easy:

  1. Place the light about 16–24 inches from your face, at a slight angle.
  2. Turn it on for 20–30 minutes each morning, ideally before 10 a.m.
  3. Keep your eyes open and go about your normal activities—like reading, eating, or working—while staying within range of the light.
  4. Be consistent—use it daily during fall and winter months for best results.

Who Can Benefit from Light Therapy?

  • People with Seasonal Affective Disorder
  • Individuals with shift work sleep disorders
  • Those experiencing jet lag
  • People living in northern climates with long winters
  • Anyone who feels sluggish or low in energy during darker months

Feel Like Yourself Again This Winter

If fall and winter weigh on your mood, energy, and motivation, light therapy could help lift the cloud. Phothera’s SAD Solutions lights are designed to provide a safe, effective, and non-invasive way to take back your mornings and restore your rhythm.