Sleep
Pineal gland
Melatonin
The "darkness" hormone that signals night-time and promotes sleep.
What it does
- Regulates the sleep–wake cycle (circadian rhythm)
- Rises in the evening, falls in the morning
Too much
- Too much (or badly timed supplements) can cause grogginess and vivid dreams
Too little
- Low or mistimed melatonin (e.g. from evening screens) disrupts sleep
Keeping it balanced: Dim light and screen-free time before bed, plus morning daylight, support natural melatonin.
Sources & references
Think a hormone may be out of balance?
The symptoms of hormonal excess and deficiency are non-specific — tiredness, weight change, low mood and poor sleep have many everyday causes. No hormone problem can be self-diagnosed from a symptom list.
Diagnosis needs blood tests interpreted alongside your history, sometimes repeated at set times of day because many hormones vary hour to hour. Speak to a GP if symptoms are persistent; seek urgent care for severe symptoms such as confusion, fainting, chest pain or extreme thirst with frequent urination.
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