Do men have significant hormonal cycles?
Short answer: yes.

Although clearly the infradian changes in steroid hormones in females are quite "obvious", other changes are less evident, but happen nonetheless in males as well as in females.

Most of the hormones produced by endocrine organs such as the hypothalamus (a region at the base of the brain) or the hypophisis are not secreted in a continuous manner but rather in pulses. The exact frequency/amplitude etc. of these pulses can be different depending on the species considered, but (as fare as we know) the undelying mechanism are fairly conserved.*

In general, you can find circadian (~24 h), ultradian (&lt;24h) and infradian (>24h) rhythms.

For instance these graphs show the concentration of cortisol, aldosteron and renin in a man, showing a strong circadian rhythm.


From: Charloux et al. - Am J Physiol Endocrinol Metab 1999

You can see that on top of the circadian rhythm, an ultradian pulsatility (every ~2-3h) is also quite clear.

Another example is that of GH (growth hormone): here you see secretion of GH in an healthy women (top) and an healthy men (bottom)


From: van den Bergh et al. - J Clin Endocrinol Metab. 1996

Many other hormones show this type of rhythmicity in males, such as testosterone, LH, GnRH, and probably many other.

I am not aware of long term studies on this matter.



* Actually, the mechanisms underlying pulsatility are still poorly understood.