Light Therapy Lamp for Seasonal Affective Disorder: How to Use It

To use a light therapy lamp for seasonal affective disorder, sit at the distance where it gives 10,000 lux and use it for 30 minutes every morning, soon after you wake. Keep the lamp above eye level and tilted down. Many people feel better within a week, and four weeks is enough to judge it.¹²

That is the protocol from the trials, and each part matters. A lamp used at the wrong distance or the wrong time of day gives a much smaller dose than the studies used.

How to use a SAD lamp, step by step

Step	What to do	Why
Dose	10,000 lux for 30 minutes	The dose used in trials such as CAN-SAD3
Distance	Sit where the maker rates 10,000 lux, typically 11 to 30 inches	Less light reaches you as you move back2
Timing	Within 10 minutes of waking	Early-morning light gave the best results45
Angle	Above eye level, tilted down toward your eyes	Less glare, and the lower retina may respond more67
Gaze	Read, eat or work. Do not stare into it	The light only needs to reach your eyes2
Schedule	Every day, weekends included, fall to spring	Sleeping in on weekends may stop it working28
Trial	Give it 4 weeks	Long enough to see if it works for you1

How much light you need: 10,000 lux for 30 minutes

Bright light therapy is a dose: brightness at your eyes multiplied by time. The trial standard is 10,000 lux for 30 minutes.³ Yale’s winter depression program treats brightness and time as a trade-off and advises aiming for at least 7,000 lux.¹

Light at your eyes	Session length
10,000 lux	30 minutes
5,000 lux	about 60 minutes
2,500 lux	about 120 minutes

Equivalent doses, per Yale’s light therapy group.¹ The light levels chart shows how these compare with daylight and indoor rooms.

The 10,000 lux on the box is true at one distance only. Yale says the maker should state the distance where the lamp reaches 10,000 lux, typically 11 to 30 inches, and that sitting farther back gives you less.² When researchers from Rochester and Yale measured 24 light therapy devices, only seven larger light boxes met their basic criteria. Some sold as 10,000 lux reached it only at unreasonably close range, over a small area or with harsh glare.⁹

Size matters too. The Center for Environmental Therapeutics (CET) recommends a light area over 200 square inches, because with a small panel a slight head turn drops the dose.⁶

You can check your own setup with a lux meter held at eye level, facing the lamp. Yale notes that phone apps using the front camera can also measure lux and found them quite accurate.¹ The how many lux guide explains what the readings mean.

What time of day to use a light therapy lamp

Early morning, within minutes of waking. In 42 people with SAD, morning light shifted the body clock earlier and evening light shifted it later. In an expanded group of 80, early-morning light beat both late-morning and evening sessions.⁴

The best timing is set by your internal clock, not the wall clock. Light given 7.5 to 9.5 hours after melatonin starts rising in the evening produced twice the remission rate of light given 9.5 to 11 hours after: 80% versus 38%, in groups of about 20 people each.⁵

Melatonin is hard to measure at home, so clinicians estimate its timing from the Morningness-Eveningness Questionnaire (MEQ). Lower scores mean a later chronotype. These start times are a selection from Michael and Jiuan Su Terman’s table, which they call a best guess to adjust from.⁵

MEQ score	Start the 30-minute session at
16–18	8:45 a.m.
27–30	8:00 a.m.
39–41	7:15 a.m.
50–53	6:30 a.m.
62–65	5:45 a.m.
73–76	5:00 a.m.
85–86	4:15 a.m.

Light therapy timing for night owls

If you are a night owl, your start time falls later on the clock. In most cases it is still earlier than you would wake on your own. The Termans’ rule of thumb: start within 10 minutes of waking, and for every 30 minutes you usually sleep beyond 6 hours, get up 15 minutes earlier, up to 1.5 hours earlier. Someone who sleeps from 11:30 p.m. to 7:30 a.m. would get up at 6:30 for their light.⁵

If that is too hard at first, start at your usual wake time and move the session earlier over several days.⁵ Yale’s clinicians say waking early gets easier as treatment continues.² Do not overshoot, though. Light timed too early often causes waking too early with no way back to sleep, and evening light that runs too late often causes trouble falling asleep and a wired feeling.⁵

Not sure where you fall? The chronotype quiz estimates it from your sleep on free days. Outdoor light on top of lamp sessions is covered in the morning sunlight guide.

Where to put the lamp: angle and position

Above eye level, tilted down toward your eyes, slightly to one side. CET says the box should project downward at an angle, raised on adjustable legs or a stand, and that boxes tilted up toward the face increase glare.⁶ The Termans warn against lamps that shine up from below the eyes, which they call the “ski slope” effect.⁵

There may be a biological reason as well. In a lab study of 9 people, light reaching the lower half of the retina, which is where light from above lands, suppressed melatonin. The same light on the upper half did no better than darkness.⁷ That was a small melatonin study, not a depression trial.

You do not need to look into the light. Yale’s program says to keep the box in your field of view while you read or eat.²

How long until a SAD lamp starts working

Yale’s program says people often notice improvement within 1 week, while the full effect can take 3 to 6 weeks.² In the CAN-SAD trial, the light group was ahead of the fluoxetine group at week 1, and the two ended up equal.³

Daily use matters. Yale says treatment may fail if you sleep in on weekends, and some people need 45 minutes or more for a full response. Once symptoms improve, some can drop to 20 to 30 minutes.²

NIMH describes light therapy running from fall to spring.⁸ Stopping too early has a cost: in one study of short courses, every patient relapsed within 3 weeks of stopping, most within 1 week. Experienced patients tend to continue through April, and stopping then needs no taper.⁵

Starting before symptoms appear is far less proven. A 2019 Cochrane review found only one usable trial, with 46 people, and rated the evidence very low quality.¹⁰

Does a light therapy lamp work for seasonal affective disorder?

Yes. The evidence is consistent, though most trials are small.

• An early meta-analysis. Pooling 8 trials, a 2005 analysis found an effect size of 0.84 for bright light in SAD, similar to most antidepressant drug trials. Dawn simulation, a light that brightens before you wake, also helped (5 trials, effect size 0.73).¹¹ See sunrise alarm clocks for that approach.
• A larger, stricter one. A 2020 meta-analysis of 19 randomized trials found bright light beat placebo on depression scores (standardized mean difference −0.37; 18 trials, 610 patients) and on response (risk ratio 1.42; 16 trials, 559 patients). Risk of bias was moderate to high.¹²
• Against an antidepressant. In CAN-SAD, 96 patients got either 10,000 lux for 30 minutes each morning or fluoxetine 20 mg for 8 weeks. Response was 67% in both groups and remission 50% versus 54%. Fluoxetine caused more agitation, sleep disturbance and palpitations.³

On our evidence scale this earns an A: several meta-analyses and randomized trials pointing the same way, with modest effect sizes.

Does a light therapy lamp help depression that isn’t seasonal?

The evidence is newer and smaller, but mostly positive.

• 2005 meta-analysis. Bright light alone helped nonseasonal depression (3 trials, effect size 0.53). Added to antidepressants in 5 older trials, it showed no benefit (effect size −0.01).¹¹
• Cochrane review, 2004. Across 20 studies the overall result fell short of significance, and it rested mainly on studies lasting under 8 days. Benefits were significant in high-quality studies and with morning light.¹³
• Placebo-controlled trial, 2016. In 122 adults over 8 weeks, 10,000 lux for 30 minutes each early morning beat placebo (effect size 0.80). Light plus fluoxetine did best (1.11). Fluoxetine alone did not beat placebo. Remission was 43.8% with light, 58.6% with the combination and 30.0% with placebo.¹⁴
• 2024 meta-analysis. Across 11 trials and 858 patients, adding bright light raised remission from 23.5% to 40.7% and response from 38.6% to 60.4%.¹⁵

For depression that isn’t seasonal, a lamp is best used alongside care from a clinician, not instead of it.

SAD lamp side effects

Side effects are common in the first days, and most are mild.

• In 70 people with SAD using 10,000 lux, 32 (45.7%) reported side effects and 9 had two or more. Headaches and eye or vision problems were the most common. Almost all were mild and short-lived.¹⁶
• In a 5-day study of 10,000 lux sessions, headache, eye strain, glare, seeing spots, blurring and irritation fell from 34% on day 1 to under 10% by day 5. Among 83 patients using a downward-tilted box, nausea, headache, jitteriness and eye irritation appeared in 6% to 16%.⁵
• Hypomania is the serious one. In a Cochrane review of nonseasonal depression trials, it was about five times as common with bright light as with control treatment (risk ratio 4.91; 1 extra case for every 8 people treated).¹³

Eye damage has not shown up in studies of medical-grade boxes. Fifty patients had eye exams before and after 10,000 lux treatment; 17 followed for 3 to 6 years, with 60 to 1,250 hours of total exposure, showed no eye abnormalities.¹⁷ Yale notes that no studies have followed yearly use over many years.¹⁸

Problem	What to try
Headache or eye strain	Sit farther back for a few days18
Feeling wired or overstimulated	Cut sessions to 15 minutes for a week or two18
Waking too early	Move the session later5
Trouble falling asleep	Move the session earlier; no evening use5
Unusually high mood or energy	Stop and call your doctor. It can signal hypomania18

Who should not use a SAD lamp without a doctor

Condition	Why	What to do
Bipolar disorder	Light can trigger hypomania or mania18	Use only under a psychiatrist’s supervision
Retinal disease, such as macular degeneration	Yale does not recommend bright light treatment18	See an eye doctor first
Glaucoma or cataract	Some have used light therapy, with monitoring5	Get eye checks during treatment
Over 65	Yale advises an eye check first18	See an eye doctor first
Light-sensitizing drugs	Some sensitize the eye even to visible light5	Ask your prescriber

Bipolar disorder. Supervised trials show light can help bipolar depression when timed carefully. In a 46-patient trial of people on mood stabilizers, 7,000 lux at midday gave 68.2% remission versus 22.2% with dim placebo light, and no one switched into mania or hypomania.¹⁹ A meta-analysis of 4 such trials (190 patients) found manic switches in 1.1% with light and 1.2% with control.²⁰ In rapid-cycling bipolar disorder, early-morning light appears riskier than midday light.⁵

Medications. Drugs reported to make the eye sensitive to visible light include lithium, imipramine, phenothiazines, St. John’s wort, melatonin, chloroquine, hydrochlorothiazide and tetracycline.⁵ Yale suggests avoiding bright light treatment while taking a photosensitizing drug, and checking with your doctor if you have been told to avoid sunlight.¹⁸ NIMH also says people with certain eye diseases or on such medications may need medical supervision.⁸

Severe depression. A lamp does not replace treatment. If symptoms are severe or include thoughts of self-harm, contact a doctor. In the US you can call or text 988.

Choosing a lamp comes down to the same numbers: the distance where it reaches 10,000 lux, light area, glare and UV filtering. Our light therapy lamp rankings sort lamps on those specs.

Footnotes

1. Yale School of Medicine, Department of Psychiatry. How to obtain a light box. Updated February 4, 2025. ↩ ↩² ↩³ ↩⁴ ↩⁵

2. Yale School of Medicine, Department of Psychiatry. Treatment for SAD. Updated February 4, 2025. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

3. Lam RW, Levitt AJ, Levitan RD, et al. The Can-SAD study: a randomized controlled trial of the effectiveness of light therapy and fluoxetine in patients with winter seasonal affective disorder. American Journal of Psychiatry. 2006;163(5):805-812. doi:10.1176/ajp.2006.163.5.805 ↩ ↩² ↩³ ↩⁴

4. Terman JS, Terman M, Lo ES, Cooper TB. Circadian time of morning light administration and therapeutic response in winter depression. Archives of General Psychiatry. 2001;58(1):69-75. doi:10.1001/archpsyc.58.1.69 ↩ ↩²

5. Terman M, Terman JS. Light therapy for seasonal and nonseasonal depression: efficacy, protocol, safety, and side effects. CNS Spectrums. 2005;10(8):647-663. doi:10.1017/s1092852900019611 ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵

6. Center for Environmental Therapeutics. How to select a light box. ↩ ↩² ↩³

7. Glickman G, Hanifin JP, Rollag MD, et al. Inferior retinal light exposure is more effective than superior retinal exposure in suppressing melatonin in humans. Journal of Biological Rhythms. 2003;18(1):71-79. doi:10.1177/0748730402239678 ↩ ↩²

8. National Institute of Mental Health. Seasonal affective disorder. NIH Publication No. 23-MH-8138, revised 2023. ↩ ↩² ↩³

9. Oldham MA, Oldham MB, Desan PH. Commercially available phototherapy devices for treatment of depression: physical characteristics of emitted light. Psychiatric Research and Clinical Practice. 2019;1(2):49-57. doi:10.1176/appi.prcp.2019.20180011 ↩

10. Nussbaumer-Streit B, Forneris CA, Morgan LC, et al. Light therapy for preventing seasonal affective disorder. Cochrane Database of Systematic Reviews. 2019;3:CD011269. doi:10.1002/14651858.CD011269.pub3 ↩

11. Golden RN, Gaynes BN, Ekstrom RD, et al. The efficacy of light therapy in the treatment of mood disorders: a review and meta-analysis of the evidence. American Journal of Psychiatry. 2005;162(4):656-662. doi:10.1176/appi.ajp.162.4.656 ↩ ↩²

12. Pjrek E, Friedrich ME, Cambioli L, et al. The efficacy of light therapy in the treatment of seasonal affective disorder: a meta-analysis of randomized controlled trials. Psychotherapy and Psychosomatics. 2020;89(1):17-24. doi:10.1159/000502891 ↩

13. Tuunainen A, Kripke DF, Endo T. Light therapy for non-seasonal depression. Cochrane Database of Systematic Reviews. 2004;(2):CD004050. doi:10.1002/14651858.CD004050.pub2 ↩ ↩²

14. Lam RW, Levitt AJ, Levitan RD, et al. Efficacy of bright light treatment, fluoxetine, and the combination in patients with nonseasonal major depressive disorder: a randomized clinical trial. JAMA Psychiatry. 2016;73(1):56-63. doi:10.1001/jamapsychiatry.2015.2235 ↩

15. Menegaz de Almeida A, Aquino de Moraes FC, Cavalcanti Souza ME, et al. Bright light therapy for nonseasonal depressive disorders: a systematic review and meta-analysis. JAMA Psychiatry. 2025;82(1):38-46. Published online October 2, 2024. doi:10.1001/jamapsychiatry.2024.2871 ↩

16. Kogan AO, Guilford PM. Side effects of short-term 10,000-lux light therapy. American Journal of Psychiatry. 1998;155(2):293-294. doi:10.1176/ajp.155.2.293 ↩

17. Gallin PF, Terman M, Remé CE, et al. Ophthalmologic examination of patients with seasonal affective disorder, before and after bright light therapy. American Journal of Ophthalmology. 1995;119(2):202-210. PubMed 7832227 ↩

18. Yale School of Medicine, Department of Psychiatry. What are the risks of light treatment? Updated February 4, 2025. ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

19. Sit DK, McGowan J, Wiltrout C, et al. Adjunctive bright light therapy for bipolar depression: a randomized double-blind placebo-controlled trial. American Journal of Psychiatry. 2018;175(2):131-139. doi:10.1176/appi.ajp.2017.16101200 ↩

20. Hirakawa H, Terao T, Muronaga M, Ishii N. Adjunctive bright light therapy for treating bipolar depression: a systematic review and meta-analysis of randomized controlled trials. Brain and Behavior. 2020;10(12):e01876. doi:10.1002/brb3.1876 ↩