The claim gets passed around online in variously inflated forms. Some versions say women need two extra hours. Others say it's because women's brains are more complex. Most of the pop-science framing is either wrong or exaggerated. But underneath the noise, there's a real and more interesting story, and it's worth telling accurately rather than in TikTok shorthand.
What the research actually says
The most commonly cited source is work from the Sleep Research Centre at Loughborough University, led by the late Professor Jim Horne. His research found that women tend to need, on average, about twenty minutes more sleep per night than men. Twenty minutes, not two hours. The study attracted a lot of attention partly because it got attached to a specific theory: that women's brains tend to engage in more multitasking during the day, and therefore need marginally more restorative time at night.
The multitasking explanation is the weakest part of the research. The twenty-minute finding itself is more robust and has been echoed in other studies. A large study using objective actigraphy rather than self-report found women sleep around eleven minutes longer than men on average, though with meaningful individual variation. The direction is consistent across studies; the magnitude is modest.
Why the difference exists
The explanation is probably less about brain complexity and more about sleep architecture and biological differences. Women tend to have more slow-wave sleep, which is deeper and more restorative, but also tend to have more fragmented sleep overall. The fragmentation comes from a mix of biological and social factors: hormonal fluctuations across the menstrual cycle, thermoregulatory differences, pregnancy and postpartum disruption, perimenopausal and menopausal hot flushes, and, statistically, a higher likelihood of being the parent who wakes when a child cries.
Women also have a slightly different circadian rhythm on average. They tend to fall asleep earlier and wake earlier, with a body temperature curve that shifts fractionally earlier in the day. None of this is deterministic, and individual variation within each sex dwarfs the between-sex averages, but the patterns hold up statistically.
Why do women need more sleep than men?
The best evidence-based answer is that women's sleep is more often disrupted, so they need slightly more total time in bed to achieve equivalent restorative sleep. This is distinct from claiming women have a higher biological sleep need; the difference may be about sleep efficiency rather than raw requirement.
Consider what gets measured. Sleep duration is the total time asleep. Sleep efficiency is the percentage of time in bed actually spent sleeping. Sleep quality incorporates architecture, fragmentation, and subjective rest. Women, on average have slightly longer sleep duration, slightly lower sleep efficiency in some studies, and higher rates of reported insomnia. Put together, this paints a picture of women sleeping for longer to compensate for sleeping slightly less efficiently.
The insomnia gap is real
Women are roughly 40% more likely than men to develop insomnia. This isn't a reporting artefact; it shows up in objective measures as well. The risk factors that drive it, including hormonal cycling, higher rates of anxiety disorders, higher caregiving burden, and specific vulnerabilities during pregnancy and menopause, are mostly not shared with men.
This is one reason the "women need more sleep" framing is slightly off. It's not that women's bodies demand more; it's that women's lives and biology produce more obstacles to sleep, and more time in bed is needed to overcome them.
Menstrual cycle effects
Across the menstrual cycle, sleep quality varies measurably. In the luteal phase, the week before a period, many women experience more fragmented sleep, lower slow-wave sleep, and more night waking. Progesterone has a sedating effect in some phases and a disrupting effect in others, depending on the interaction with body temperature and other hormones. Some women barely notice these shifts. Others find the premenstrual week produces noticeably worse sleep.
Pregnancy disrupts sleep in every trimester for different reasons: first trimester through hormonal shifts, second through physical discomfort, third through everything at once. Postpartum sleep disruption is well-documented and severe, and it persists longer than the baby's own sleep difficulties for most new mothers.
The menopause piece
Perimenopause and menopause produce some of the most significant sleep disruptions women experience across the lifespan. Hot flushes and night sweats fragment sleep directly. Declining oestrogen affects the architecture of sleep through multiple mechanisms, including its role in thermoregulation and neurotransmitter function. Sleep apnoea risk also increases after menopause; many cases go undiagnosed because the symptoms are attributed to menopausal changes generally.
A sleep environment that handles temperature well becomes considerably more important during these years. Bedding choices have a bigger effect than people expect; duvets for all-season comfort at lighter togs allow heat to dissipate rather than accumulate, reducing the frequency and intensity of temperature-related awakenings. This isn't a cure for menopausal sleep disruption, but it removes one contributing factor.
Does this mean women should aim for more sleep?
If you're a woman who feels rested on the same amount of sleep as the men around you, there's nothing wrong with that; the averages are just averages, and individual needs vary enormously. If you're a woman who consistently needs more sleep than people around you, that's also probably normal, and trying to match someone else's sleep duration isn't going to serve you.
The more useful question is whether your current sleep feels restorative. If you're waking refreshed and functioning well, the total is right, whatever the clock says. If you're not, the issue is probably about sleep quality rather than just duration, and adding an extra hour isn't guaranteed to fix it.
The caveat worth noting
Research on sex differences in sleep has historically focused on cisgender women, and the data on trans and non-binary populations is thin. What's known about sleep is shaped by hormones, body composition, and social circumstances as much as by chromosomal sex, so the generalisations above should be read as statistical patterns rather than fixed rules for any individual body.
The honest summary: yes, women on average need a bit more sleep than men, but the difference is smaller than the internet suggests, and it's driven mostly by more frequent disruption rather than a higher base requirement. The implication isn't that women should feel entitled to extra sleep; it's that women's sleep tends to need more protecting, and the factors that protect it are worth taking seriously.
