The neurotransmitter changes regulated by acupuncture for insomnia are mainly reflected in the following aspects:

Increase serotonin levels: Serotonin is an important neurotransmitter that participates in regulating mood, sleep and wakefulness. Acupuncture, by stimulating specific acupoints such as Shenmen and Neiguan, can promote the synthesis and release of serotonin, thereby helping to regulate the sleep cycle and improve insomnia symptoms. Studies show that acupuncture treatment can increase the content of serotonin by 20% to 30%, exerting sedative and sleep-inducing effects.
Increase the level of gamma-aminobutyric acid (GABA) : GABA is an inhibitory neurotransmitter that can reduce the excitability of neurons and promote relaxation and sleep. Acupuncture helps to inhibit overly active neural activity and improve sleep quality by regulating the function of the nervous system and increasing the content of GABA. For instance, needling acupoints on the head such as Baihui and Yintang can increase the content of gamma-aminobutyric acid and inhibit the overly active activity of the amygdala.
Regulating dopamine and norepinephrine levels: Dopamine and norepinephrine are excitatory neurotransmitters associated with arousal and attention. Acupuncture can regulate the levels of these neurotransmitters, achieving a balance between sleep and wakefulness, thereby improving insomnia. For instance, during sleep, the decline in dopamine levels helps to fall asleep, and acupuncture can assist in regulating this process.
Balancing acetylcholine levels: Acetylcholine is a neurotransmitter associated with arousal and cognitive function. Acupuncture helps maintain a normal sleep-wake cycle by regulating the level of acetylcholine and reduces sleep disorders caused by abnormal acetylcholine levels.