Orexin A

How it works

A brain neuropeptide that activates both orexin receptors, keeping you awake and alert and increasing appetite. Losing the cells that make it causes narcolepsy.

What it is used for

Narcolepsy, daytime sleepiness and sleep deprivation.

What the evidence says

In sleep-deprived monkeys, orexin A reversed the effects of lack of sleep. Human data is limited; drugs that activate orexin receptors are in clinical trials.

Side effects and cautions

Its safety is unknown. It may raise heart rate and blood pressure and cause insomnia.

Half-life

Minutes: it is quickly broken down in blood

Makes sense for

• Narcolepsy and daytime sleepiness research

Does not make sense for

• High blood pressure or heart disease
• Insomnia