Low plasma testosterone levels in cluster headache.

Serum levels of various hormones have been estimated in cluster headache and non-cluster headache controls. Cluster headache patients were studied prior to, during, and after attack. During the cluster phase, plasma testosterone levels were low, whereas levels were within the reference limits. Normal values were also found in control patients with non-cluster headache. It is suggested that a decrease of plasma testosterone levels in episodic cluster headache should be viewed in context with disordered REM sleep in cluster headache.