Residential lighting has changed significantly in the last three decades, which influences human physiology. Traditional incandescent bulbs were the standard, which was then replaced with compact fluorescent (CFL) and light-emitting diode (LED) bulbs. Each technology has different impacts on circadian rhythms and melatonin levels. The concern is: are we swapping energy efficiency in the home for our health? Read on to learn how to choose the best home lighting and blue light protective options for you and your patients.
Melatonin secretion has an endogenous pattern, with increased synthesis and release in darkened environments to help with sleep. Daylight and artificial light at night suppress melatonin secretion, which is why we tell our patients to turn off devices before bedtime. Even household lighting at night can contribute to this effect, and it’s important to choose lighting that’s better aligned with natural circadian rhythms. Some studies have shown that typical home lighting induces significant melatonin suppression, up to 50%.
Chronic circadian disruption is linked to several chronic health conditions, including sleep and mood disorders, obesity, diabetes, cardiovascular disease, and cancer.
The Study
This study, published in Nature’s Scientific Reports, compared 52 incandescent, CFL, and LED lamps and eight blue-light-filtering lenses to assess their effects on melatonin. The Melatonin Suppression Value (MSV) is a metric that quantifies how much exposure to artificial light at night inhibits the body’s natural production of melatonin. It’s expressed as a percentage, representing the extent to which evening light exposure suppresses nighttime melatonin levels relative to complete darkness. In this study, MSV was determined with an exposure duration of 30-90 minutes, since this mimics typical daily life exposure to artificial light before sleep.
Incandescent light bulbs are characterized by “warm” correlated color temperatures (2700-3000 K). CFLs and LEDs are available in both “warm” (3000 K) and “cool” white (5000 K) options. “Cool” white sources have higher short-wavelength (blue) spectrum irradiance. Blue light suppresses endogenous melatonin production but is important for alertness during the daytime.
Daylight and artificial light at night suppress melatonin secretion, which is why we tell our patients to turn off devices before bedtime. Even household lighting at night can contribute to this effect, and it’s important to choose lighting that’s better aligned with natural circadian rhythms. Some studies have shown that typical home lighting induces significant melatonin suppression, up to 50%.
Blue-light filtering lenses are available in various colors; in this study, clear, yellow, light brown, and medium brown lenses were assessed. Lenses that aim to reduce wavelengths in the specific blue-green or “cyan” wavelength (~ 460-530 nm) range are important for reducing melatonin suppression. Lenses designed to mitigate the “blue light hazard” in the ~ 400-460 nm range are marketed, although there is debate as to their efficacy.
Four lenses from clinical practices with claims to protect from “blue light hazard” (~ 400-460 nm wavelength range) and four from online retailers were studied. After combining the transmittance spectrum of the lenses with the irradiances of the lamps, MSVs were recalculated to determine blue light blocking efficacy.
Here are a few notable stats from this study*:
- Incandescent lamps had the lowest MSV (1.5%) among the lamps.
- “Cool” CFL and “cool” LED lamps had a similar MSV (12.1% and 12.3%), and a higher MSV than all other lamp groups.
- “Warm” LEDs had a 3.4-fold (236%) reduction in MSV (3.6%) compared to “cool” LEDs.
- Tunable LED lamps, known as “circadian” lamps, change from “cool” to “warm” and produce significant reductions in melatonin suppression, from 10% to 0.1% MSV.
- For the blue light filtering lenses, the “brown” lenses performed best by reducing estimated melatonin suppression to below 0.3%. All four lenses reducing the specific blue-green or “cyan” wavelength (~ 460-530nm) range had statistically significant reductions in MSV.
- Relative to wearing no lenses, there was no statistically significant reduction in MSV for clear control lenses or any of the four ophthalmic lenses blocking “blue light hazard” (~ 400-460 nm) from clinical practices.
Conclusions
Melatonin suppression magnitudes depend on both the duration and intensity of light exposure at night, so it’s important to limit both. Modern lighting is everywhere and likely here to stay as it’s becoming harder to find incandescent bulbs anymore.
From this study, the best options for protecting against melatonin suppression would be to choose “brown” tinted glasses, or those limiting the “cyan” wavelength (~ 460-530 nm) range, for wear around the house in the evening before bedtime. And to choose incandescent, or “warm” versus “cool” lighting at night.
*For brand information, please refer to the article.
Reference
Terán, E., Yee-Rendon, C.M., Sosa-Arámbula, H.J. et al. Home lighting, blue-light filtering, and their effects on melatonin suppression. Sci Rep 16, 2850 (2026). https://doi.org/10.1038/s41598-025-29882-7
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