Where your DNA places you among other people, and the studies behind it.
Not tailored to your result, and not medical advice
Work With Your Natural Timing: There's no inherently better or worse chronotype, but aligning your schedule with your biology tends to support sleep and daytime functioning. If early obligations clash with an evening lean, shifting wake and sleep times earlier in small steps (around 15 minutes at a time) and holding them consistently is gentler than abrupt changes. A steady sleep-wake schedule, including on free days, helps reduce the mismatch known as social jet lag. Sleep Foundation
Use Light Strategically: Light is the strongest signal that sets the circadian clock. Bright light in the morning tends to shift the clock earlier (useful for night owls trying to wake sooner), while dim lighting and reduced screen exposure in the evening support an earlier sleep onset. Daylight is far brighter than typical indoor lighting, so getting outside in the morning is an effective everyday tool. Sleep Foundation
Consider the Timing of Exercise: Controlled studies of exercise phase-response curves suggest that activity in the morning or early afternoon tends to advance the circadian clock, while exercise late in the evening can delay it - though the effect varies with chronotype. If you're trying to shift earlier, scheduling workouts earlier in the day may help reinforce that direction alongside its broader health benefits. Journal of Physiology
Approach Melatonin Carefully: Melatonin is sometimes used, often alongside morning light, to nudge the circadian clock earlier. Timing matters more than dose, and effects are modest. Because melatonin is a hormone and over-the-counter products vary in quality, discuss whether and how to use it with a healthcare provider, especially if you take other medications. Journal of Clinical Endocrinology & Metabolism
How much of this is genetic?
Genetics explains 45% of why people differ in this trait. The rest is environment, daily habits and chance.
Heritability estimate: von Schantz et al. 2015, Sci Rep (Baependi)
Background and further reading
Chronotype describes your body's natural tendency toward morningness or eveningness - when you naturally prefer to sleep, wake, and feel most alert. It's governed primarily by your circadian clock, a set of molecular oscillators in the suprachiasmatic nucleus (SCN) of the hypothalamus that cycle approximately every 24 hours.
Genetic Basis: Chronotype is a polygenic trait shaped by many common variants of small effect. A genome-wide association study of 697,828 people from the UK Biobank and 23andMe identified 351 loci linked to being a morning person, up from 24 previously known [1]. Many of these loci sit in or near core circadian-clock genes - including PER1, PER2, PER3, CRY1, and CLOCK - that drive the molecular feedback loop keeping cells on a roughly 24-hour cycle. An earlier 23andMe study of 89,283 people had already flagged 15 morningness loci, seven of them close to established clock genes such as RGS16 and PER2 [2]. Twin and family studies place the heritability of diurnal preference at roughly 40-50% [3].
Environmental Factors: Light is the most powerful cue that sets the circadian clock, so genetics is only part of the picture. Artificial lighting, evening screen use, shift work, caffeine, and social schedules all shift the chronotype you actually express. Age matters too: diurnal preference drifts toward eveningness through adolescence, peaks in lateness around age 20, and gradually returns toward morningness in later adulthood [4]. Because genes interact with these factors, your observed sleep-wake timing can differ from the tendency your DNA suggests.
The published research behind your score, and the variants it draws on.
9 published scores from 4 studies
The chronotype score combines 9 polygenic scores drawn from 4 published studies.
Roenneberg T, et al. A marker for the end of adolescence. Current Biology (2004)
These traits are influenced by some of the same genes and variants as this one
Insomnia: Chronic difficulty falling asleep, staying asleep, or achieving restorative sleep.
Content updated August 2026.
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