Protocol · Light
Bright light therapy
Seasonal affective disorder symptom relief
Evidence type: Randomized trials
The graded dose: 10,000 lux white light, about 30 minutes, in the morning within about an hour of waking, daily during the symptomatic season. Frequency in the evidence: 7 sessions per week. Program length in the evidence: 4 to 8 week trial periods in the studies. The grade attaches to this dose; below it, the grade does not apply.
The caveat: The consumer energy and focus claim grades C. The graded evidence is for depressive symptoms.
Time cost
210 minutes / week
30 min daily counted at face value, even though sessions often overlap breakfast or desk work.
Dollar cost
About $8 / month
10,000 lux light box $30 to $200 one-time (basis: device-amortized)
Every claim, graded
Each outcome this protocol is claimed to deliver carries its own grade and its own kind of evidence. A strong secondary outcome never launders a weak popular claim: the popular claim prints at its own grade, next to the headline.
| Claim | Grade | Evidence | What the data show |
|---|---|---|---|
| Seasonal affective disorder symptom relief | B+ | rctRandomized trials | Golden 2005 (American Journal of Psychiatry): meta-analysis of bright light trials for SAD, effect size 0.84 (0.60 to 1.08); dawn simulation 0.73.Golden RN et al., American Journal of Psychiatry, 2005 |
| Nonseasonal major depression improvement (adjunctive or monotherapy) | B- | rctRandomized trials | Bright light effect size 0.53 in Golden 2005; Lam 2016 (JAMA Psychiatry) supports adjunctive and monotherapy use in nonseasonal MDD. Later critical reviews find smaller, possibly transient effects (overall SMD about minus 0.54) with methodological caveats: a real but moderate effect.Lam RW et al., JAMA Psychiatry, 2016; Golden RN et al., 2005 |
| Energy, focus, and circadian support for general users (the popular consumer claim)Popular claim, graded on its own evidence | C | mixedMixed evidence | Morning light advances circadian phase, which is established physiology; consumer energy and focus claims beyond the depression outcomes rest on that mechanism and thin direct data.Longevity Lab Report evidence review, 2026-10-18 |
Dose and response
The studied modern dose is 10,000 lux for about 30 minutes in the morning. The older studied variant is 2,500 lux for 2 hours. Dawn simulation is a studied variant of the same device class (effect size 0.73). Consumer 'energy and focus' use outside the depression indications is a different, thinner claim (see outcomes).
Equipment that can deliver this dose: Home device.
Harms and cautions
Harms live in this ledger, not inside the grade: the grade is evidence for the claimed outcomes in the studied population.
Medication interactions
Flagged medication classes: Photosensitizing medication. If you take any of these, the standing rule is a clinician conversation first, never a bare instruction from a website.
Photosensitizing medication interactioncaution
Medication users check photosensitivity before use
Source: Longevity Lab Report evidence review, 2026-10-18
Goal conflicts and timing
No goal conflicts in this record.
Time of day is the protocol: morning, within about an hour of waking; late-evening use is the known error. Daily through the symptomatic season is the studied pattern.
Population exclusions and other cautions
Hypomania or mania induction in bipolar disorderserious
Exclusion or clinician supervision required
Source: Longevity Lab Report evidence review, 2026-10-18
Eye disease (retinal conditions)caution
Clinician check first
Source: Longevity Lab Report evidence review, 2026-10-18
Headache and eyestraincaution
Common and mild
Source: Longevity Lab Report evidence review, 2026-10-18
Evening use can delay sleep phasecaution
Scheduling harm: morning placement is the protocol
Source: Longevity Lab Report evidence review, 2026-10-18
Can you measure it yourself?
Seasonal affective disorder symptom relief
- Metric
- PHQ-9 score
- Method
- PHQ-9 questionnaire
- Baseline
- PHQ-9 at start
- Minimum run
- 2 weeks; retest: Weekly during use
Noise note: A 5-point PHQ-9 change is the established minimum clinically important difference; energy self-ratings are too noisy to carry a decision alone.
Outcomes without a measurement block carry none because no effect is established for them: a self-experiment cannot test a claim the evidence has not made.
Goals served
Stress, Energy
Derived from outcomes grading B- or better, never hand-assigned.
Experience gate
beginner and up (gated for safety)
Users with bipolar disorder are clinical-flagged; the ledger, not the gate, carries that point.
Applicability
targeted
Applies to a specific goal or population, not broadly.
Grades are research summaries, not medical advice. Decisions about your own stack belong with your clinician.
Longevity Lab Report
Protocol news, graded when it happens.
The grades on this page stay free. The email is the week's longevity and biotech news in plain English: biotech news, expert moves, what is working, and new supplements and peptides, each story linked to the grades on this site.
Frequently asked questions
What grade does Bright light therapy get?
At the studied dose (10,000 lux for about 30 minutes each morning), Bright light therapy grades B+ for seasonal affective disorder symptom relief, on randomized trials. The grade attaches to that dose; below it, the grade does not apply.
How much time does Bright light therapy take each week?
At the graded dose, 210 minutes per week, counted as session time plus standard overhead, travel excluded. Dollar cost: 10,000 lux light box $30 to $200 one-time.
Does Bright light therapy deliver its most popular claim?
The popular claim (Energy, focus, and circadian support for general users) grades C. Morning light advances circadian phase, which is established physiology; consumer energy and focus claims beyond the depression outcomes rest on that mechanism and thin direct data.
Who should not use Bright light therapy?
Hypomania or mania induction in bipolar disorder. Exclusion or clinician supervision required. The full harm ledger is on this page, and the medical line applies: decisions about your own stack belong with your clinician.
Sources
- Golden RN et al. The efficacy of light therapy in the treatment of mood disorders: meta-analysis. American Journal of Psychiatry, 2005. (2005)
- Lam RW et al. Efficacy of bright light treatment in nonseasonal major depression. JAMA Psychiatry, 2016. (2016)
Last reviewed October 18, 2026
- 2026-10-18|Initial grading from the 2026-10-18 protocol inventory evidence review.
- 2026-10-18|Update: goal assignments are now recorded for each outcome individually, not only for the record as a whole. No grades, doses, or claims changed.