Light therapy lamps: how to choose one and when to use it

When outdoor morning light is out of reach, a bright-light lamp can supply some of the strong light your body clock responds to. These devices, often called light therapy lamps or light boxes, are much brighter than normal room lighting, which is the point: your clock reacts to intensity, and indoor light is usually too dim to do much ¹².

This is general category guidance to help you compare options, not a set of product reviews, ratings, or test results. It covers the specs that matter and, just as important, the ones that are mostly marketing.

What a bright-light lamp is for

A bright-light lamp delivers a large amount of visible light at close range, standing in for daylight you cannot get outdoors. Because your body clock responds to how much light actually reaches your eyes, and because that response depends on both intensity and timing, a lamp is most useful as a morning light source on dark mornings ¹³. Think of it as a daylight substitute, not a cure for anything.

Lux at your real distance is the number that counts

Many lamps advertise a headline figure such as 10,000 lux. The catch is that lux falls off steeply as you move away from the source, roughly with the square of the distance, so a lamp rated at 10,000 lux right at its face may deliver a fraction of that where you actually sit. The useful question is not the headline number but how much light reaches your eyes at a comfortable working distance.

• Check the distance the rating assumes. A lamp rated at a stated lux at 40 to 50 centimeters is more honest than one rated at its surface.
• Bigger light-emitting surfaces make it easier to get strong, even light without pressing your face to the panel.
• Position matters as much as the spec. A modest lamp used close and consistently can outperform a brighter one parked across the desk.

UV filtering and eye comfort

You want the visible brightness, not ultraviolet. Choose a lamp that states it filters out UV. Beyond that, look for even, glare-free light that is comfortable to sit beside without staring into it; the light should reach your eyes indirectly, from above or to the side, not by looking straight at the panel.

Size, placement, and daily practicality

The best lamp is the one you will actually use each morning, so practicality often beats specifications. A lamp that fits where you already spend your first waking half hour, at the breakfast table, beside a laptop, or at a desk, gets used. One that requires a special session in a special spot tends to gather dust.

• Match the lamp to a place you already sit in the morning.
• A stable stand and an adjustable angle make it easy to get the light coming from the right direction.
• Larger panels are easier on the eyes at a given brightness; compact ones travel better. Pick for your real routine.

When to use it, and for how long

Timing follows the same logic as natural morning light. Use the lamp in the morning, ideally within the first hour or so of waking, to reinforce an earlier, steadier clock ³⁴. Sit beside it while you do something you would be doing anyway. Session length depends on the lamp and your distance from it; brighter and closer means less time. Avoid bright light from a lamp late in the evening, since evening light can push your clock later and delay your night signal ¹⁵.

Start conservative. Begin with shorter sessions and see how you feel over a week before extending. As with outdoor light, consistency from day to day matters more than any single long session.

Specs that sound impressive but rarely matter

Some numbers on the box tell you little about whether a lamp will actually help.

• Color-temperature marketing. Cooler or warmer white is mostly a comfort preference. What your clock responds to is getting enough light at the right time, so do not over-index on a specific shade of white.
• A very high headline lux with no distance stated. As above, a big figure measured at the panel face can shrink to a fraction where you actually sit. Always read the distance the rating assumes.
• Extra modes and colors. Reading modes, night lights, and color-changing features are convenience extras, not the reason a lamp works.

Spend your attention on honest lux at a real distance, UV filtering, a comfortable large surface, and whether the lamp fits the spot where you start your morning. Those four decide almost everything.

Fitting a lamp around real daylight

A lamp is a stand-in, not a replacement for the outdoors. On days when you can get outside in the morning, do that first: natural light is far brighter than any bedside device and needs no setup ⁴. Save the lamp for dark mornings, early starts before sunrise, and stretches of gloomy weather when real daylight is genuinely scarce. Used that way, it fills the gap rather than competing with the strongest signal you already have.