Most of your daily testosterone is produced during sleep, and the majority of that during deep sleep in the first half of the night. Growth hormone follows the same pattern.
Restrict healthy young men to five hours a night for one week and daytime testosterone falls 10 to 15 per cent. That is one week of moderate restriction, not extreme deprivation.
For women, disturbed sleep raises cortisol, worsens insulin sensitivity, and increases appetite through changes in ghrelin and leptin. It is one of the reasons weight becomes harder to manage through menopause.
So sleep is not adjacent to hormonal health. It is where a large part of it happens.
Eight hours in bed with fragmented architecture leaves you worse off than seven solid ones. This check asks about both.
The signs that quality is the problem rather than duration: waking unrefreshed despite adequate hours, waking repeatedly through the night, needing an alarm every day, and afternoon sleepiness that arrives regardless of what you ate.
Obstructive sleep apnoea. It fragments sleep hundreds of times a night without waking you fully, and it suppresses testosterone directly.
The signs are loud snoring, witnessed pauses in breathing, morning headaches, and unrefreshing sleep despite adequate hours. In women it often presents differently, as insomnia, anxiety or fatigue rather than the classic snoring picture, which is why it goes undiagnosed.
If several of those apply, a sleep study is worth more than any supplement.
A consistent wake time, seven days a week. This anchors your body clock more powerfully than bedtime does.
Morning daylight within an hour of waking, ten to twenty minutes outside.
Temperature. Core body temperature must fall for sleep to begin, which is why a cool bedroom and a warm bath ninety minutes before bed both work.
Alcohol. It shortens sleep onset and wrecks the second half of the night. This is the single most common cause of three-in-the-morning waking.
Caffeine timing. Its half-life is five to six hours, so an afternoon coffee is still working at bedtime.
For women in perimenopause, night sweats are often the actual cause, and treating them is a sleep intervention.
Related reading: Why you wake up tired after eight hours · Sleep apnoea and testosterone · How hormones hijack your sleep · The 90-minute rule
Educational only, not medical advice.