By Roy, founder Last updated 14/10/2026
Updated 14 October 2026
Sleep changes gradually through adult life. It gets lighter, more broken and a bit shorter, and plenty of people notice it in their 40s. The documented reasons are a body clock that drifts earlier, less deep sleep, more night-time trips to the toilet, and a life that carries more stress, caffeine and alcohol than it used to. For women, perimenopause adds another layer.
What helps first is unglamorous and well supported: the same bed and wake times, daylight early in the day, caffeine finished by early afternoon, less alcohol, and CBT-i (a structured sleep therapy) through your GP if poor sleep has settled in. Supplements sit on top of that. Magnesium glycinate, glycine and L-theanine have small trials behind them, and none of those trials was run on men over 40 specifically.
Why can't I sleep like I used to?
Mostly because several small things changed at once, and no single one is the culprit. The Sleep Health Foundation makes a point worth knowing: big changes in sleep are more likely to come from stress, lifestyle and health changes than from ageing itself (Sleep Health Foundation). That is good news, because those are the parts you can do something about.
Here is what the sources document.
Your sleep gets lighter and more broken. A meta-analysis of 65 studies and 3,577 healthy people found that in adults, total sleep time, sleep efficiency, deep (slow-wave) sleep and REM sleep all fall with age, while the time it takes to fall asleep and the time spent awake in the night go up (Ohayon et al, Sleep, 2004). Only sleep efficiency kept falling after 60, which suggests most of the other shifts had already happened by then. The changes looked smaller when the people studied were screened for health problems, which fits the point above. Healthdirect puts it simply: older people sleep more lightly and for shorter spans (Healthdirect).
You still need the same amount. Healthdirect says most adults need 7 to 9 hours, and that your needs settle around age 20. The Sleep Health Foundation calls "we need less sleep when we're older" a myth. If you are sleeping less than you used to and feeling it, that is not your body quietly needing less.
The body clock drifts earlier. The Sleep Health Foundation says that after middle age the body clock gradually shifts and the hormones that help us sleep are released earlier in the day. Some people feel sleepy earlier in the evening and wake in the early hours. The same page notes that people make less melatonin as they age.
You wake for the toilet more. Needing to pass urine at night becomes more common with age in both men and women. A review of the research notes that the first trip often lands in the first few hours of the night, when deep sleep is happening (Fine et al, F1000Research, 2017). Caffeine and alcohol are both diuretics, which makes it worse (Sleep Health Foundation).
Caffeine lasts longer than you think. The Sleep Health Foundation says caffeine peaks within 30 to 70 minutes, keeps working for 3 to 7 hours, and can take up to 24 hours to clear. In one trial, 400mg of caffeine taken six hours before bed still cut sleep time (Drake et al, J Clin Sleep Med, 2013). The foundation adds that older people may be more sensitive. The 3pm coffee that never bothered you at 28 might now.
Alcohol costs you the second half of the night. A drink helps many people nod off, but the Sleep Health Foundation says sleep after alcohol is more fragmented, with more waking, more night sweats and more toilet trips in the second half of the night. People often say alcohol hits harder as you age. The research is thinner than you would expect: one breath-test study found higher blood alcohol after the same dose in women over 60, but no difference between women aged 35 to 47 and women aged 21 to 25 (Davies and Bowen, 1999). So your 40s are not proof that your tolerance has dropped. The broken second half of the night is the documented cost. We cover it in what a nightcap does to the rest of the night.
Life got busier. The Sleep Health Foundation lists stress, chronic pain, medication changes and long-term health conditions as common reasons sleep slips, and says these are things we can do something about.
What changes for women in their 40s?
Hormones. Perimenopause can start up to 10 years before your final period, so a sleep change in your early 40s can be part of it. The Sleep Health Foundation says around 40 to 60% of women have disturbed sleep through peri- and post-menopause. The full picture, including night sweats, MHT and CBT-i, is in our perimenopause and sleep guide.
What changes for men in their 40s?
Testosterone falls gradually with age, and a 2022 review in Reviews in Endocrine and Metabolic Disorders says most of that fall is linked to things that come with ageing, such as extra body fat and illness, rather than age itself (Liu and Reddy, 2022). The same review reports the link running both ways: short and lost sleep are associated with lower testosterone. That is an association, so it does not show that sleep loss is causing a problem in any one man.
If a bad run of sleep comes with changes in mood, libido or energy that do not lift, that is a conversation for your GP. A supplement will not answer it.
What helps first?
These are the habits both the Sleep Health Foundation and Healthdirect put first, and they are free.
Fix your times. Go to bed and get up at about the same time every day, including weekends. The foundation says going to bed too early can also disturb sleep. Healthdirect suggests limiting time in bed to about 8 hours. If you are awake for 20 to 30 minutes, get up, sit somewhere dim and quiet, and go back when you feel sleepy.
Get daylight early. The foundation says natural daylight during the day improves sleep at night, and the best time is the early part of the day. A bright screen or bright room late in the evening lowers melatonin.
Finish caffeine early. Sources differ on the exact cut-off. The Sleep Health Foundation says at least four hours before bed in one summary and 3 to 7 hours in another, and Healthdirect says 3 to 7 hours. If your sleep is already poor, the foundation notes that some people cut caffeine after lunch.
Stop alcohol at least 4 hours before bed. Healthdirect says at least 4 hours. The foundation says 3 to 4 hours, and earlier if you are sensitive.
When is CBT-i worth asking your GP about?
When poor sleep has become a pattern of its own. CBT-i is a structured therapy that works on the habits and thinking that keep you awake. The Sleep Health Foundation says it usually takes about 4 to 8 sessions and is recommended as a best first treatment by the Royal Australian College of General Practitioners.
In Australia you start with a GP. A GP can set up a mental health treatment plan that lets you claim up to 10 sessions a year through Medicare, and the foundation also lists low-cost online CBT-i programs.
What can a sleep supplement do, and what can't it?
It can add a small amount to a good routine. It cannot replace one, and none of these options changes the age-related shifts above.
| Option | What the evidence says | How you get it in Australia |
|---|---|---|
| Schedule, light, caffeine and alcohol changes | Put first by the Sleep Health Foundation and Healthdirect | Free |
| CBT-i | Recommended best first treatment for persistent poor sleep | GP, Medicare-rebated sessions, or online programs |
| Melatonin | Shifts body timing. Around 7 minutes faster to fall asleep on average | Prescription. Pharmacist-only for modified-release 2mg or less, aged 55 and over |
| Magnesium glycinate | One 2025 trial (about 80% women, aged 18 to 65) found a small benefit on a sleep score after 4 weeks | Supermarket, chemist, online |
| Glycine | Small trials at 3g before bed. Industry-funded | Chemist, online |
| L-theanine | One small trial at 200mg found better sleep scores. Mostly studied for stress | Chemist, online |
| Herbal teas and extracts | The Sleep Health Foundation says there is little convincing evidence that they help sleep | Supermarket, chemist |
Magnesium. The best recent trial gave 250mg of elemental magnesium as bisglycinate to 153 adults with poor sleep. After four weeks the magnesium group improved slightly more than placebo on a sleep score, with a small effect size and a result right on the edge of significance (Schuster et al, Nature and Science of Sleep, 2025). More in magnesium glycinate for sleep.
Glycine. In one small trial, healthy people whose sleep was cut by a quarter for three nights took 3g before bed and reported less fatigue the next day (Bannai et al, Frontiers in Neurology, 2012). The authors work for a glycine maker. This is the thinnest evidence of the three.
L-theanine. A small crossover trial of 30 adults, average age 48, gave 200mg a day for four weeks and found better sleep-quality scores than placebo (Hidese et al, Nutrients, 2019). It is the closest match to this page's reader, and still only 30 people.
Melatonin. It is a timing signal, not a sedative, and the average effect in trials is modest. In Australia it is prescription only for most adults. The one pharmacist-only lane is a modified-release tablet of 2mg or less, in packs of 30 or fewer, for adults aged 55 and over (TGA). If you are in your 40s, that means a GP visit. The full rules are in is melatonin available over the counter in Australia.
Where Settl fits. Settl is a nightly sleep drink for adults, men and women. One scoop in cold water gives you 730mg of magnesium glycinate (146mg elemental), 3,000mg of glycine and 200mg of L-theanine, plus chamomile extract and myo-inositol, with an electrolyte layer and no melatonin. Two honest notes. The glycine and L-theanine doses match the trial doses above, but the 146mg of elemental magnesium is lower than the 250mg used in the magnesium trial. And Settl itself has not been trialled. It belongs in the supplement row of that table, after the routine, not instead of it. If your head is wired at bedtime, see tired but wired.
When should I see my GP about my sleep?
See your GP if loud snoring happens most nights or someone notices you stop breathing in your sleep. The Sleep Health Foundation says regular loud snoring is not normal and should be checked, and to seek help if a partner notices something wrong with your breathing. Also go if you are sleepy through the day despite enough hours in bed, if your mood or concentration is slipping, or if the problem has lasted for months. If you take prescription medicine, talk to your GP or pharmacist before adding any supplement.
Common questions
What is the best sleep supplement for men over 40 in Australia? No supplement has strong evidence for men over 40 specifically. Magnesium glycinate, glycine and L-theanine are the reasonable ones to try alongside a steady routine, and all three are sold without a script. Melatonin needs a prescription until 55 for most people.
Why is my sleep worse after 40? Sleep gets lighter and more broken through adult life, the body clock shifts earlier, and toilet trips, caffeine, alcohol and stress add up. In women, perimenopause is often part of it.
Do I need less sleep as I get older? No. Most adults need 7 to 9 hours across adult life, according to Healthdirect and the Sleep Health Foundation.
Is it my testosterone? Possibly a small part. Testosterone falls with age and is linked with sleep loss, but the link is an association and runs both ways. If poor sleep comes with other changes that do not lift, ask your GP.
Why do I wake up at 3am now? Sleep runs in cycles of about 90 minutes and gets lighter with age, so a toilet trip, a noise or a busy head is more likely to turn into a full wake-up. More on 3am waking.
The short version, and where Settl sits
Fix the times, get light early, finish caffeine by early afternoon, and cut back the evening drink. If poor sleep has stuck, ask your GP about CBT-i. Supplements sit on top of that.
Get to sleep faster. Wake less at 3am. Sleep deeper. Wake up refreshed. That is what Settl is built for: magnesium glycinate, glycine, L-theanine, chamomile extract and myo-inositol, with an electrolyte layer so eight hours without water does not wake you dried out and needing to get up. That is about 1,000mg of sodium a scoop, so if you have been told to watch your salt, check with your GP first. More on the electrolyte side here.
No melatonin. Zero sugar. Vegan. Every dose is printed on the ingredients page and on the tub. Packed in Sydney, in a TGA-licensed GMP facility.
One scoop, cold water, before bed.
Start For $69.99 Then $89.99 a month. Cancel, pause or skip anytime.
Or buy a single tub, $99 One-time order. Nothing renews.
Cheers, Roy
Sources: Sleep Health Foundation, "Ageing & Sleep", "Caffeine and Sleep", "Caffeine, Food, Alcohol, Smoking and Sleep", "Sleep Hygiene: Good Sleep Habits", "Sleep Myths", "Herbal Remedies and Sleep", "Menopause and Sleep" and "Cognitive Behavioural Therapy (CBT-i)"; Healthdirect, "Sleep"; Ohayon et al, Sleep, 2004; Fine et al, F1000Research, 2017; Drake et al, Journal of Clinical Sleep Medicine, 2013; Davies and Bowen, 1999; Liu and Reddy, Reviews in Endocrine and Metabolic Disorders, 2022; Schuster et al, Nature and Science of Sleep, 2025; Bannai et al, Frontiers in Neurology, 2012; Hidese et al, Nutrients, 2019; Ferracioli-Oda et al, PLoS ONE, 2013; TGA, "Regulation of melatonin products in Australia"; Jean Hailes, "How long does menopause last?". This article explains the general research picture in plain English and isn't medical advice. Talk to your GP or pharmacist about what's right for you.