Bon Charge Blue Light Blocking Light Bulb (red)

This is the red bulb for the room you are in right before sleep. Bon Charge lists a 630 nm wavelength and a spectrometer result of “100% of blue and green light blocked between 380nm-580nm”. If that holds, it puts out almost nothing in the 480 to 490 nm range the body clock responds to most, which is why red ranks above amber for bedrooms and night-time bathroom trips. In a 12-person lab study, red light at 40 lux did not reduce nighttime melatonin while blue light at the same level did (Figueiro and Rea, 2010).

The spec sheet is the weak point. It gives a colour temperature of 2800K and a brightness of 600 to 700 lm. Neither fits a pure red light: colour temperature describes white light, and those exact figures also appear on Bon Charge’s separate Low Blue Light Bulb. Treat the brightness as unknown until the brand publishes a measured figure. The spectrometer result is shown as an image without a lab name.

What it does badly: like most single-colour bulbs, it cannot be dimmed, and Bon Charge says it should not go in a dimmable fixture. Everything in the room turns red, so reading labels or picking clothes is hard.

How it compares: BlockBlueLight’s red Twilight bulb makes almost the same claims (630 nm, 380 to 580 nm blocked) for $21.95 and lists a more believable 400 lm. If you mainly need light for night-time trips rather than a lamp, a red plug-in night light puts out far less light. For living rooms in the early evening, the brighter amber Sweet Dreams bulb is easier to live with.

Bon Charge also sells a Low Blue Light Bulb (warm yellow, 2800K) at the same price, which is not a red bulb and makes a weaker low-blue claim.