Most people looking this up have already had a few hard winters. The energy goes first, then the plans, then the mood. By spring it lifts, and it’s easy to decide it was just the weather.
If that pattern comes back every year, light therapy is worth understanding properly. Here’s how to use a SAD lamp, what to look for when buying one, who should check with a professional first, and what to do when a lamp isn’t enough.
Does light therapy work for seasonal depression?
For many people, yes. CAMH describes light therapy as the main treatment for seasonal affective disorder (SAD), with many people helped by exposure to bright artificial light.
It isn’t the only option. When researchers directly compared light therapy with a form of CBT adapted for SAD, the National Institute of Mental Health reports that both were equally effective, with some symptoms improving slightly faster on light therapy.
The leading explanation is daylight. Shorter days are thought to disrupt your circadian rhythm and shift serotonin and melatonin, which affect mood and sleep. Bright light in the morning is meant to help reset that rhythm.
Is it seasonal depression or the winter blues?
The winter blues are common and tend to be mild. Seasonal depression is a form of depression that returns on a seasonal pattern and gets in the way of daily life. NIMH notes that symptoms usually start in late fall or early winter, ease in spring and summer, and last about four to five months of the year.
Winter-pattern SAD can look like:
- Low mood that holds for weeks
- Fatigue that sleep doesn’t fix
- Losing interest in things you normally enjoy
- Trouble concentrating
- Oversleeping and craving carbohydrates
It doesn’t always look like falling apart. From the outside, not much changes. You still go to work, answer messages and show up for family.
What goes quietly is everything optional: the friend you keep rescheduling, the gym, the hobby. You come home with nothing left and get short with the people closest to you, and you call it being tired. If everyone relies on you, it can be hard to see that as depression, because you’re still getting everything done.
You don’t need to be certain it’s SAD before you talk to someone. Your family doctor can assess what’s going on. Some people also have the reverse pattern, with summers that feel heavier rather than winters.
How do you use a SAD lamp?
Use a 10,000-lux light therapy lamp every morning, soon after you wake, from fall through spring. The details matter:
- Use it in the morning. NIMH describes sessions as usually first thing in the morning. Cleveland Clinic warns that using a lamp at night can affect your sleep.
- Plan for 20 to 45 minutes. Cleveland Clinic says most people use a lamp for 20 to 30 minutes a day, and NIMH describes about 30 to 45. Follow your lamp’s instructions and ask your doctor if you’re unsure.
- Sit 16 to 24 inches away. Place the lamp on your desk or table, off to the side. It’s meant to sit near you while you do something else, so you don’t stare into it.
- Keep going daily. Light therapy isn’t a one-time fix. NIMH describes daily use from fall to spring.
Many people notice a change within the first couple of weeks. If a few weeks of daily use hasn’t shifted anything, that’s useful to know, and a good reason to talk to someone.
What should you look for in a SAD lamp?
Look for a lamp that clearly states its brightness and UV filtering. The words “SAD lamp” on a listing don’t tell you much on their own, so check these before you buy one in Canada:
| What to check | What to look for |
|---|---|
| Brightness | 10,000 lux is the level NIMH describes. Cleveland Clinic gives a range of 2,500 to 10,000 lux. |
| UV filtering | A stated UV filter. NIMH notes that light boxes filter out potentially damaging UV light. |
| Light type | Full-spectrum light, which Cleveland Clinic notes is what SAD devices use. Blue, red and green light products are sold for other uses, such as skin health or migraines. |
An ordinary lamp isn’t a substitute: a light box is about 20 times brighter than normal indoor light. Tanning beds aren’t a substitute either. We don’t recommend specific brands.
Side effects and who should check first
Side effects are usually mild. CAMH lists nausea, headaches and eye strain, and Cleveland Clinic also lists blurry vision and fatigue. A shorter session or sitting further back may help. Talk to your doctor if they don’t settle.
Check with your doctor before starting if you:
- Have bipolar disorder. Light therapy may not be safe for you, because bright light has been linked to manic symptoms.
- Have an eye condition, such as macular degeneration.
- Take medication that makes you more sensitive to light. Cleveland Clinic names some anti-inflammatories and antibiotics as examples.
- Are sensitive to light.
When a SAD lamp isn’t enough
Most people have tried a lot by the time they reach out. They’ve pushed through, gone to bed earlier, started vitamin D, or bought a lamp and used it when they remembered. Many have told themselves it’ll pass by spring, because it did last year. So the question usually isn’t “what is this?” It’s “why does this keep happening, and do I have to go through it every year?”
A lamp can help with the biology of the season. It doesn’t change what you do once your mood drops: the cancelled plans, the isolating, the “I’ll deal with it in spring.” In session, we map your pattern, including when it starts and what goes first. Then we plan around it, often using CBT, so you have something in place before next winter rather than starting from zero. We also look at what you tell yourself when you can’t keep up, because that part doesn’t always lift with the daylight.
Light therapy and talk therapy aren’t the only options. CAMH notes that medication and other treatments can also help, alone or in combination. Whether medication is right for you is a conversation for your doctor.
At Clear Moon Therapy, therapy for depression is available in person in Etobicoke or online across Ontario. Book a free 15-minute consultation to talk it through. We reply in 24–48 hours, and there’s no waitlist.
If you’re thinking about suicide or feel unsafe, call or text 9-8-8 at any time. This isn’t something to wait out.
What else do people ask?
Do you get vitamin D from a SAD lamp?
No. SAD lamps filter out UV light, and your skin needs UV to make vitamin D. As for supplements, NIMH says studies on vitamin D as a treatment for SAD have mixed results. Ask your doctor before relying on them.
What colour light is best for seasonal depression?
Devices made for SAD use full-spectrum light, according to Cleveland Clinic. Coloured lights are generally sold for other purposes, so check that a lamp is meant for SAD.
How long does light therapy take to work?
Many people notice a change within the first couple of weeks of daily use. Consistency matters, so try to use it at the same time each morning.
What are the worst months for seasonal depression?
It varies from person to person. Symptoms usually start in late fall or early winter and ease in spring. Tracking your own pattern for a year can help you see when yours tends to begin.
Can you use a light therapy lamp at night?
Morning is the better choice. Using a lamp at night can affect your sleep, which is often already disrupted. If mornings feel impossible, that’s worth mentioning to your doctor or therapist.