When to start using a SAD lamp UK: the signs that say start now
The calendar says October. Your body is more precise: waking groggy in the dark, a slump at three, a craving for toast. Here is how to read the signals that decide when to start using a SAD lamp in the UK, month by month from September to March, and how to use one so it does something.
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Quick answer
For most people in the UK the right moment to start is early to mid October, a fortnight or so before the clocks go back. The signal that overrides the date is your own: waking groggy in the dark, a mid-afternoon slump and a craving for carbs, three mornings running. If you had a bad winter last year, start in late September instead.
Most answers to when to start using a SAD lamp in the UK hand you a month and stop. October is the honest average, but an average is no use in a dark kitchen on 28 September wondering whether this is the week. The date frames the answer; what you notice in yourself settles it.
One thing to say plainly first. A SAD lamp is a wellbeing tool for the flat mood and low energy that arrive with short days, and the NHS notes that some people find light therapy helpful while the evidence remains mixed. It is not a treatment for diagnosed depression, and if your low mood is heavy, lasting or frightening, a GP comes before any lamp.
The signs it is time to switch one on
The lamp stands in for morning daylight, so the first place to look is the morning. If sunrise now lands after your alarm and you are getting dressed under the big light, the daylight your body clock expects has already gone. For a seven o'clock riser in London that is the second half of September; in Glasgow or Aberdeen, a week or two earlier.
Then look at how you wake. Groggy in the dark, hitting snooze twice, pulled out of deep sleep rather than surfacing from it. When that turns up most weekdays rather than the odd one, it is the clearest single signal there is.
The afternoon tells you too. A slump between two and four that coffee does not touch, and with it a pull towards toast, biscuits, pasta, anything starchy and quick. Afternoon carbohydrate craving is a recognised feature of winter low mood, and it tends to appear before the mood itself does.
Motivation is the quieter tell: the gym session that gets moved, the Saturday plan you would rather cancel. Alone that is tiredness; alongside dark mornings and the slump, it is the pattern.
Finally, the mirror. Broken sleep in a dark bedroom shows on the face fast: puffy eyes on waking, shadows concealer does not quite cover, skin that looks grey and flat rather than dry. If your morning puffy eye routine needs more effort than it did in August, that is your sleep talking, and the lamp works on the cause rather than the symptom.
The ninety-second check: was it dark when the alarm went off, did you wake heavy, did you slump and reach for carbs yesterday? Three yeses, three days running, is the start signal. Two is a fortnight away. One is September doing what September does.
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Different starting points for different people
If you had a bad winter last year. Do not wait for the signals. Anyone who recognises the pattern does better starting in mid to late September, before the slump arrives, because a lamp is far better at holding a mood steady than at pulling one back up. This is the one case where the calendar beats the signal.
If you live in the north. Midwinter sunrise in Inverness is roughly three quarters of an hour later than on the south coast, and sunset correspondingly earlier. Rule of thumb: north of Manchester, bring everything here forward by two weeks; Shetland and Orkney, three.
If you should talk to a GP first. Bipolar disorder, because bright light can tip mood the other way. Any eye condition, including macular degeneration, glaucoma, retinal problems or diabetes affecting the eyes. And any medication that makes skin or eyes light-sensitive, which includes some antibiotics, St John's wort, lithium and some acne treatments. None rules out a lamp; each makes it a conversation before a purchase.
Month by month from September to March
These dates assume southern England and a seven o'clock alarm. Adjust by the regional rule above, and remember the weather moves things a fortnight either way between years: a bright, dry October delays the signals, a wet grey one brings them on.
September
Nothing yet, for most people. Sunrise moves from about half past six to just before seven over the month and the evenings are still usable. Take a baseline: note how you wake and whether the afternoon slump is there. If you are in the bad-winter-last-year group, start in the last two weeks.
October
The start month. By mid October sunrise is past half past seven and the three-yes check starts coming back positive for a lot of people, so start on the first run of dark, heavy mornings. The clocks go back on the last Sunday, 25 October in 2026, which buys a brighter morning for a fortnight and takes the evening away. If you have not started by the clock change, start that week.
November
Peak month. Sunset is before half past four by mid month, commutes are dark at both ends, and the first frosts arrive. If you are only now noticing the pattern, start today rather than waiting for a better week. Winter skin starts to complain now too, so read how long dry winter skin takes to recover before blaming your moisturiser for what is really lost sleep.
December
The shortest day falls around 21 December, with sunset before four in the south and nearer half past three in Scotland. Christmas breaks routines and a lamp is easy to skip when breakfast is at eleven. Keep the session, even a short one: the darkest mornings are still ahead.
January
Darker mornings than December, because sunrise keeps slipping for a fortnight after the solstice: past eight in London, nearer nine in the far north. This is the month people who started in October are glad they did. Do not judge the lamp on January.
February
The light comes back, roughly two extra minutes a day, and by the end of the month sunrise is before seven again. It is tempting to stop here. Do not, yet: the slump returns quickly if you drop the routine, and February weather is often the greyest of the year.
March
Taper. The clocks go forward on the last Sunday, 28 March in 2027, and most people stop needing the lamp within a fortnight of that. Drop to alternate days first, then stop, and if the heaviness comes back in a wet week, go back to daily until April.
How to use one so it works
The dose is what matters, and the dose is brightness, distance and time. Get those three right and the make of lamp barely matters.
Check the lux rating and the distance it is measured at. The standard for light therapy is 10,000 lux, but that figure is only true at the distance the maker states, often 20 to 30cm for a small lamp. At arm's length a compact lamp delivers far less.
Within an hour of waking. The lamp is telling your body clock that morning has happened. Breakfast is the obvious slot, a desk is the other, and before eight beats before ten. Anything after early afternoon works against you.
30 to 60cm away, angled above or to the side. Roughly the distance from your face to a laptop screen. Set it slightly above your eyeline or off to one side so the light falls across your face rather than straight into it, which is how daylight arrives.
Eyes open, not staring. The light has to reach your eyes, so a lamp behind you, or one you close your eyes against, does nothing. Read, eat, do your skincare. Do not look directly into the panel, and no sunglasses.
20 to 30 minutes, every day, same time. Start at 15 if bright light bothers you, then build up; longer than 45 adds little and raises the odds of a headache. Consistency beats duration, so tie it to something you already do: the kettle goes on, the lamp goes on.
Use the slot for your morning face. Twenty minutes in front of a lamp is exactly the time an under-eye patch needs, and if broken sleep got you here, the puffiness is real. A cooling pair such as the grace & stella gold under-eye patches or the BIODANCE collagen peptide patches can sit on while you eat. The lamp emits no UV, so it will not tan or burn skin, but the heating is on and the air is dry, so something rich like Weleda Skin Food earns its place from November onward.
Where it goes wrong
Using it too late in the day. The commonest mistake and the one with a cost: evening light delays sleep, and worse sleep makes the next morning darker. If you have been using it after lunch and sleeping badly, move it to breakfast and give it a week.
Sitting too far away. A lamp on the far side of the desk gives you a fraction of its rated output. Measure the distance once against the maker's figure and move the lamp, not yourself. A longer session partly compensates if you cannot sit closer.
Giving up after three days. Three days tells you whether the light is comfortable, not whether it works; two weeks daily is the minimum fair trial. If nothing has changed after a month, that is real information, and the next step is a GP rather than a brighter lamp.
Eye strain and headaches. Usually a lamp that is too close, too direct or on too long in the first week. Move it to the far end of the 30 to 60cm range, angle it further off your eyeline, and cut sessions to 10 or 15 minutes for a few days. A mild headache in the first week is common; one that persists, or any change in vision, means stopping and seeing an optician or GP.
Feeling jittery or wired. Some people find long sessions leave them agitated. Shorten to 15 minutes, keep it early, and if it continues, stop. Anyone with bipolar disorder who notices racing thoughts or unusually high energy should stop straight away and talk to whoever manages their care.
Treating it as the whole answer. The lamp does one job: it puts morning light back where the season took it. It does not replace getting outside at lunchtime, moving, regular sleep or talking to someone, and the NHS lists all of those ahead of light therapy. If the low mood is deeper than a slump, or has been there for weeks whatever the weather, that is a GP appointment first.
Frequently asked questions
Does the NHS recommend SAD lamps?
The NHS says some people with seasonal affective disorder find light therapy helpful, while noting the evidence is mixed and that light boxes are not available on the NHS. Its main advice is daylight, exercise, talking therapies and, where a GP advises, medication. A lamp sits alongside those.
Can I use a SAD lamp in the evening?
It is better not to. Bright light late in the day tells your body clock it is still afternoon, which pushes sleep later and makes the next dark morning worse. If mornings are impossible, before midday is the latest sensible slot.
How long before I notice a difference?
Typically a week or two of daily use. Some people feel more awake within days, but the mood change builds slowly, which is why three days is not enough to judge it. If nothing has shifted after a month of daily use, the lamp is not the answer and a GP conversation is.
Is a daylight bulb or sunrise alarm the same thing?
No. A daylight bulb in a ceiling fitting delivers a few hundred lux where you sit, nowhere near the 10,000 lux a SAD lamp provides at close range. A sunrise alarm helps you wake more gently and pairs well with a lamp, but it is not a substitute.
Will a SAD lamp do anything for my skin?
Not directly. A proper SAD lamp filters out UV, so it will not tan, burn or age skin, and it treats no skin condition. The skin benefit is second-hand: better sleep shows up as less puffiness and a less grey complexion.
When should I stop using it in spring?
When you no longer need it, which for most people is a couple of weeks after the clocks go forward at the end of March. Taper rather than stop dead, and if the slump returns in a grey week, go back to daily until the mornings are properly light.