Can Men Have a Period? The Science of Male Hormonal Cycles

Men do not menstruate. Menstruation is the shedding of the uterine lining, and without a uterus, there is nothing to shed. But the question behind the question is more interesting than a flat “no.” Male bodies run on hormonal rhythms that shift testosterone, cortisol, and estrogen levels on daily, seasonal, and possibly monthly timescales, and those shifts can produce real changes in mood, energy, and behavior. Whether that counts as a “male period” depends entirely on how loosely you define the term.

The Daily Testosterone Cycle

The most well-documented hormonal rhythm in men is the one that resets every 24 hours. Testosterone peaks early in the morning and falls throughout the day. In both younger and older men, the drop from peak to trough is substantial: at least 43% in one study of middle-aged and young men, with the highest levels arriving around 7:00 to 7:30 a.m.¹ This is why blood draws for testosterone testing are usually scheduled first thing in the morning: a late-afternoon sample can look like clinical low testosterone simply because the test caught the daily low point.

This daily swing is large enough to matter. Testosterone influences energy, libido, confidence, and pain tolerance. A man at 7 a.m. is, in hormonal terms, operating in a meaningfully different chemical environment than the same man at 4 p.m. The rhythm is driven by signals from the hypothalamus and pituitary gland following the body’s internal clock, and it holds up across age groups, though the overall baseline gradually declines with age.

Seasonal Fluctuations in Testosterone

Beyond the daily cycle, testosterone appears to shift across the calendar year, though the research does not agree on exactly when the peaks and valleys fall. A year-long study of 16 men found a statistically significant rise in testosterone and related hormones in June, with a low point in August.² A 17-month Danish study found peak testosterone in June and July, with its lowest values in winter and early spring, and linked the variation to air temperature rather than daylight.³

Other data tell a different story. A large Italian cohort found total and bioavailable testosterone peaking from August to October and reaching a low point in March.⁴ An older American study found a seasonal peak in December for most men, with a November peak in men in their early thirties.⁵ And a two-site analysis using data from Pittsburgh and Miami found no statistically significant seasonal variation at all.⁶

The scatter is real, and it probably reflects differences in latitude, climate, sample size, and how often blood was drawn. What the research collectively shows is that testosterone is not perfectly flat across the year, but the seasonal signal is modest and inconsistent enough that you would never feel it the way you feel the daily peak-to-trough drop. If men have a seasonal “cycle,” it is a gentle wave, not a monthly cliff.

Is There a Monthly Testosterone Cycle?

This is the claim that comes closest to a literal male period, and the evidence for it is thin. One study tracked testosterone in men whose partners were trying to conceive and found a 28-day pattern in testosterone peaks, but only in men who were partnered and actively hoping for children. Unpaired men and men who did not want children with their current partner showed no such pattern. The researchers concluded this likely reflected men adjusting their hormonal responses to their partner’s menstrual cycle rather than running an independent 28-day rhythm of their own.⁷

That distinction matters. If a hormonal rhythm only appears when a man is syncing with a female partner’s cycle, it is not an intrinsic male cycle in the way the daily testosterone rhythm is. It is a response to external cues. The broader literature has not established a reliable, endogenous monthly testosterone rhythm in men. Some popular health content treats the 28-day male cycle as settled science, but the evidence does not support that. Men have daily hormonal rhythms, probable seasonal rhythms, and various reactive fluctuations in response to stress, sleep, relationships, and environment. A fixed monthly cycle independent of external triggers has not been demonstrated.

Stress, Cortisol, and Testosterone Crashes

One of the most potent disruptors of male hormonal patterns is stress. When cortisol rises, testosterone tends to fall, and this is not a vague correlation. Experimental work has shown that directly elevating cortisol levels in men, either through injecting hydrocortisone or triggering the body’s stress response, produces a rapid drop in circulating testosterone.⁸ The suppression appears to act directly on the testes rather than through the brain’s hormonal signaling chain.⁹

Chronic stress layers additional mechanisms on top. In men with type 2 diabetes, sustained cortisol elevation was linked to suppression of a binding protein (SHBG) that normally helps regulate how much testosterone is available in the body, creating a longer-lasting hormonal drag.¹⁰ The practical consequence is that men under heavy or prolonged stress can experience a hormonal downturn that mimics some of the fatigue, irritability, and low mood that people associate with premenstrual symptoms. The cause is different, but the lived experience can overlap.

The Irritable Male Syndrome

The term “Irritable Male Syndrome” was coined based on animal research, specifically on Soay rams, a breed of sheep whose reproductive axis shuts down seasonally. When testosterone drops sharply at the end of the mating season, these rams become agitated, fearful, and aggressive, with inter-male fighting injuries peaking during the withdrawal period.¹¹ The researchers described this as a behavioral state of nervousness, irritability, lethargy, and depression triggered by falling testosterone.

The concept has been extended, somewhat loosely, to human men. The analogy is not perfect because human testosterone does not crash seasonally the way a ram’s does. But the underlying principle, that rapid withdrawal of androgens can produce mood disturbance, holds up in clinical settings. Men who stop testosterone replacement therapy or discontinue anabolic steroids frequently report irritability, depression, and anxiety. During steroid withdrawal in particular, changes in serotonin-related brain chemistry appear to drive mood symptoms.¹² So while the phrase “irritable male syndrome” is more of a pop-science label than a medical diagnosis, the phenomenon it describes, mood disruption following a testosterone drop, is real and well-documented in both animals and humans.

Estrogen, Mood, and the Male Brain

Testosterone gets most of the public attention, but estrogen plays an underappreciated role in male biology. The male brain can convert circulating testosterone into estrogen locally using an enzyme called aromatase, and neurons can also produce estrogen on their own.¹³ This means that shifts in testosterone can ripple into shifts in estrogen, which in turn affect mood regulation.

Research has found that men under 60 who had depressive symptoms had higher estradiol (a form of estrogen) levels than men without depression, and this held true regardless of body weight.¹⁴ The relationship between estrogen and mood in men is not as simple as “more estrogen equals more sadness.” But it adds a layer of complexity to the idea of male hormonal cycles. When testosterone fluctuates daily, seasonally, or in response to stress, estrogen fluctuates too, and the downstream effects on mood, sleep, and emotional regulation come from the interplay of multiple hormones rather than from testosterone alone.

Do Men’s Moods Actually Cycle?

Given all these hormonal fluctuations, you might expect men to report cyclical mood changes. The data on this is surprisingly quiet. A study that tracked daily mood in men and women over 70 days, with participants unaware of the study’s focus, found no evidence of mood fluctuations over the lunar cycle in men. In fact, normally cycling women reported more pleasant moods during certain menstrual phases compared to men and women on oral contraceptives, but the groups did not differ in overall mood stability.¹⁵

This does not mean men’s hormones are irrelevant to their emotions. It means that the hormonal swings most men experience in ordinary life are either too small or too gradual to produce the kind of predictable, cyclical mood shifts that would show up in daily diaries. The daily testosterone dip is large in percentage terms but plays out over hours, not days. The seasonal variation is modest and geographically inconsistent. The stress-driven drops are real but episodic, not cyclical. Men have hormonal lives, but those lives do not follow a calendar the way a menstrual cycle does.

Sympathetic Pregnancy and Hormonal Contagion

One of the more striking examples of male hormonal change tied to an external partner is couvade syndrome, sometimes called sympathetic pregnancy. Expectant fathers in some cases develop physical symptoms, including nausea, weight gain, mood swings, and fatigue, that mirror their pregnant partner’s experience. A study of Jordanian expectant fathers found that roughly 59% reported symptoms consistent with couvade syndrome.¹⁶

These are not purely psychological. Hormonal measurements in expectant fathers have found increased cortisol, estradiol, and prolactin alongside decreased testosterone during the third trimester.¹⁷ Fathers who reported more couvade symptoms had higher prolactin and greater testosterone drops when exposed to infant stimuli.¹⁸ The mechanism is not fully understood, but the effect is measurable. A man’s endocrine system can shift in response to his partner’s reproductive state, producing real physical sensations and mood changes driven by actual hormonal movement.

The Gradual Decline With Age

The other major hormonal shift in men’s lives is the slow, decades-long decline in testosterone that begins around age 40 to 50. This is sometimes called “andropause” to draw a parallel with menopause, but the comparison is misleading. Menopause is a relatively abrupt shutdown: estrogen production essentially stops over a few years. In men, testosterone declines about 1 to 2% per year, which can eventually push some men below the threshold for clinical low testosterone, but the process is gradual and driven partly by metabolic changes related to body fat rather than by a programmed reproductive shutdown.¹⁹ Many men maintain adequate testosterone levels well into old age, while others dip below the clinical cutoff decades earlier, often in connection with obesity or chronic illness.²⁰

Calling this decline a “cycle” is a stretch, since a cycle implies recurrence. It is a one-directional trend, and a variable one. But it does mean that the hormonal environment a man experiences at 30 is different from the one he experiences at 60, with potential consequences for mood, energy, sexual function, and body composition that accumulate so slowly they are easy to attribute to “just getting older.”

Transgender Men and Persistent Menstruation

The question of whether men can have a period takes on a literal dimension for transgender men. Transgender men who have a uterus and ovaries will menstruate until testosterone therapy suppresses the cycle, and that suppression is not always immediate or complete. In one study, about half achieved cessation of menses within the first six months of testosterone injections, while roughly a third took longer than six months.²¹ A larger survey found that about 23% of participants reported persistent menstruation more than six months after starting testosterone.²²

Persistent bleeding was associated with lower testosterone levels and a lower free androgen index compared to those who achieved full cessation. In many of these cases, adjusting the testosterone dose upward resolved the issue, while some individuals required the addition of an oral progestogen, particularly those with a higher body mass index.²³ Persistent menstruation was also linked to significantly higher odds of pelvic pain, likely from ongoing estrogen and progesterone fluctuations driving uterine contractions and inflammation.²⁴

High-dose testosterone also affects the ovaries themselves. Research on ovarian tissue from transgender men found that testosterone exposure was associated with reduced follicle growth, poorer follicle health, and increased DNA damage.²⁵ This is part of how testosterone therapy eventually suppresses menstruation, but it also raises questions about long-term fertility that are still being studied.

What Primate Research Shows About Male Seasonal Rhythms

If you want to understand why male hormonal cycles exist at all, the primate literature is useful. Male rhesus monkeys show a seasonal testosterone rhythm, with levels rising during the mating season and falling afterward. But here is the interesting part: males housed where they could see and smell females but not physically access them still showed the typical seasonal pattern, while males completely isolated from females did not. The isolated males had intermediate testosterone levels during the mating season, rising somewhat but never reaching the full peak.²⁶ This suggests that male primate testosterone rhythms are not purely internal clocks but are partly driven by social and sensory cues from females.

Long-tailed macaques show a similar pattern: androgen levels rise during the conception period alongside increased aggression and mating activity, both tied to how many females in the group are cycling. Interestingly, hormone levels start climbing a month or two before the mating season actually begins, suggesting a preparatory phase.²⁷ The broader picture from primate studies is that male hormonal rhythms evolved not as autonomous cycles but as flexible systems tuned to the reproductive state of nearby females and the competitive environment among males.

The Medieval Myth of Male Menstruation

The idea that men might menstruate has a strange and uncomfortable history. In medieval Europe, a persistent belief held that Jewish men menstruated. This was rooted in humoral medicine, which held that the body needed to balance its fluids, and in anti-Semitic stereotypes that characterized Jewish men as effeminate. The theory went that most men could reduce excess bodily heat naturally, but supposedly “womanish” Jewish men could not, and therefore required a literal discharge of blood to achieve equilibrium. The supposed mechanism was hemorrhoidal bleeding, attributed to a diet of salty foods and a melancholic temperament.²⁸

The myth persisted into the early modern period and evolved alongside humoral theory. It had no medical basis whatsoever, but it illustrates how deeply the idea of gendered biological rhythms has been embedded in cultural thinking, and how easily that thinking slides into prejudice when it lacks a scientific foundation. Modern discussions of “male periods” occasionally echo this territory, especially when they frame normal hormonal variation as a medical condition or imply that men’s mood swings are equivalent to menstruation. The biological realities are worth understanding precisely because the cultural baggage around this topic is so heavy.