Do men have significant hormonal cycles?

Question

I know there's a similar question here. But that discussion dissolved into lunar cycle and a correlation with it. I want to find more towards the original question of is there a periodic hormone cycle in men. The links i have read suggest that there's probably a daily one for sure. But few hint at monthly ones too. That link seems to have very shaky science, but my biology is too weak for me to find the actual studies. Anyone else with more informed opinions? Any studies tracking purely hormone levels in men over a period of couple of months/years?

[EDIT] I understand it's clear there are cycles within the day or around the 24-hr mark now. I still am looking for studies focusing on longer term cycles like week,months etc.

Answer 1

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 (<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.

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

Answer 2

I found this -

Celec et al. (2003) Circatrigintan cycle of salivary testosterone in human male. Biological Rhythm Research 34: 305-315

Conclusion. We believe that this is the first study demonstrating the existence of circatrigintan and circavigintan rhythms of testosterone in human males. Our findings might have implications in human physiology and pathophysiology.

(circatrigintan = ~30 day period; circavigintan = ~20 day period

also:

Celec et al (2006) Infradian rhythmic variations of salivary estradiol and progesterone in healthy men Biological Rhythm Research 37: 37-44

Discussion. We believe that this is the first study to describe a 12-day (duodecimal) rhythm of salivary estradiol in men. This finding might be of importance for physiological and pathophysiological research though the pattern needs to be investigated in larger studies.

However these papers have not been widely cited so their significance is unclear. The citing articles do not lead to a body of literature on this topic.

Finally, the entire text of this book:

INTRODUCING BIOLOGICAL RHYTHMS A Primer on the Temporal Organization of Life, with Implications for Health,Society,Reproduction and the Natural Environment  Willard L. Koukkari and Robert B. Sothern. (2006) Springer, New York.

is available here. There is a long discussion of infradian rhythms in men starting at page 273.