Your body is running on a constant stream of information. Messages are sent, received, adjusted, and rerouted every second of every day, telling your body to breathe, eat, sleep, work, bathe, and yes, even have sex.
Hormones are the couriers of that system, the vehicles that get those messages across the body. They are a major part of the internal interstate that connects your brain, testes, adrenal glands, blood vessels, nerves, and tissues into a coordinated network. Just like I-75, there are downtown connectors and major interchanges along the way, some of which can become less than productive.
When you’re at the top of your game, and signals are flowing healthily, energy is steady, sleep is restorative, sex feels natural, muscles respond, and erections happen without negotiation. When one piece falters in this delicate system (signals are delayed, messages are distorted, or exits are missed altogether), a cascade can occur.
Predominant Hormones in Men’s Sexual Health
Erections are the result of precise coordination between hormones, blood flow, nerve signaling, and mental state. Testosterone, estrogen, cortisol, thyroid hormones, growth hormone, prolactin, and others alert various body systems of the intention to pursue sex and support the body’s ability to follow through.
These are some of the predominant male hormones involved with sexual health and what happens when their signals get scrambled.
Testosterone
Testosterone is the representative hormone of maleness. It’s fundamental for a healthy libido, sperm production, muscle mass, bone density, mood, and energy. Adequate testosterone helps prime the brain for sexual interest and supports the physical mechanisms required for erections.
When testosterone is too low, men may notice decreased sex drive, fewer spontaneous or morning erections, fatigue, loss of muscle, increased body fat, and mood changes. Excessively high testosterone (usually due to misaligned supplementation) can lead to acne, hair loss, mood changes, elevated blood pressure, and even increased cardiovascular risk.
Estrodial (Estrogen)
Yes, men have estrogen, and they need it. Estradiol is produced when testosterone is converted by an enzyme called aromatase. When balanced, estradiol supports libido, erectile function, sperm health, bone density, and mood.
High estradiol can contribute to low libido, erectile dysfunction, fatigue, breast tissue growth (gynecomastia), and mood changes. Low estradiol can cause bone loss, anxiety, and sexual dysfunction.
Elevated levels most commonly stem from increased conversion of testosterone to estrogen, which is frequently driven by obesity (fat tissue contains aromatase), aging, liver dysfunction, excessive alcohol use, and mismanaged testosterone supplementation. Low estradiol is usually seen alongside low testosterone or from over-suppression during hormone therapy, and can leave men feeling flat, fatigued, achy, and disconnected both physically and emotionally.
Prolactin
Prolactin levels are low in healthy men and non-pregnant women, as it’s usually associated with lactation. Made by the pituitary gland, prolactin mainly acts as a modulator in men by fine-tuning other systems; normal levels support male reproductive balance and proper signaling between the brain and testes. It fluctuates naturally throughout the day with stress, sleep, exercise, and orgasm, and appears to be involved with the neuroendocrine circuitry of ejaculation.¹
Too much prolactin interferes with the effects of testosterone, leading to low libido, erectile dysfunction, infertility, fatigue, and male breast enlargement. Certain medications (notably antidepressants, antipsychotics, and opioids), untreated hypothyroidism, chronic kidney or liver disease, and benign pituitary tumors called prolactinomas are common causes. Because prolactin is produced by the pituitary, persistently elevated levels are a red flag that warrants further evaluation rather than symptom-based treatment alone.
Cortisol
Most of us know cortisol as the “stress hormone.” In short bursts, it’s meant to be helpful – it sharpens focus, mobilizes energy, and gets the body ready to respond to immediate demands. It raises blood sugar, increases alertness, and temporarily suppresses non-essential functions so you can do what you need to do under duress.
However, when cortisol is chronically elevated, it becomes disruptive. It suppresses testosterone production, interferes with sleep, increases abdominal fat, and drains energy and libido. Men under constant stress from work, overtraining, or even untreated health conditions can experience a lag in the bedroom. High cortisol levels crowd the hormone highway and can make erections less reliable, desire dip, or both.
Thyroid Hormones
Thyroid hormones primarily regulate metabolism and energy. Both underactive and overactive thyroid states can mimic or worsen symptoms of low testosterone, including fatigue, mood changes, reduced libido, and erectile dysfunction.
Thyroid disorders disrupt the Hypothalamic-Pituitary-Gonadal (HPG) axis, which affects sex hormone levels. Thyroid hormones influence testicular tissue development and function, impacting sperm production and hormone release, and issues can affect the nerves and muscles essential for erection and ejaculation.
Symptoms of a thyroid disorder can appear subtle at first, and sometimes overlap with Low-T symptoms; when evaluations focus too narrowly on testosterone alone, other drivers can be missed. Correcting thyroid levels under an endocrinologist’s care typically resolves or improves these sexual dysfunctions. When additional support is needed, a urologist specializing in men’s health can help coordinate care and tailor treatment to restore sexual function.
SHBG (Sex hormone-binding globulin)
SHBG determines how much testosterone is actually available to your tissues.
High SHBG can leave you with “normal” total testosterone but low free testosterone: symptoms persist despite reassuring numbers on paper. That can seem confusing, so here’s an illustration to help explain how this works: SHGB binds to free testosterone, carrying it through the bloodstream and preventing it from being used immediately. Free testosterone is “free” to enter tissues, while SHBG-bound testosterone is largely inactive until released. Healthy SHBG levels maintain a balance between bound and free testosterone, ensuring there is enough to “go around.” If there is too much binding happening, tissues don’t get the testosterone they need.
Testosterone can look normal on lab results because most standard blood tests measure total testosterone, which includes both bound and free testosterone. If SHBG is high, total testosterone may appear within the normal range, but the fraction that is free and actually usable by the body is low.
Low SHGB levels do the opposite and allow for more free testosterone. On the surface, that can sound like a good thing. But even though there’s more available testosterone, it can be a marker for metabolic syndrome, a cluster of conditions that can include high blood pressure, elevated blood sugar, excess abdominal fat, and abnormal cholesterol levels. It also increases the risk of heart disease. Common causes of this kind of hormone shift include obesity and excess body fat, insulin resistance or diabetes, an underactive thyroid, excess androgen exposure (including testosterone therapy), and conditions such as Cushing’s disease.
DHEA (Dehydroepiandrosterone)
DHEA is a precursor hormone. Produced by the adrenal glands, DHEA also supports them, feeds into both testosterone and estrogen pathways, and acts in the central nervous system. Low levels are associated with fatigue, low libido, mood changes, and sexual dysfunction. DHEA levels drop in men primarily due to natural aging (a dip around 30), but they can also be reduced by adrenal gland issues (like Addison’s disease), pituitary dysfunction, severe stress or burnout, certain medications (like glucocorticoids), and other systemic illnesses that disrupt DHEA production.
High levels, often from unsupervised supplementation, can also cause problems and confuse the body’s natural hormone feedback loops, producing acne, oily skin, mood swings, hair loss, irritability, and gynecomastia.
Growth Hormone (GH)
Growth hormone has emerged in fitness and longevity circles for its perceived anti-aging, body-composition, and performance benefits. Its appeal is in its involvement in tissue repair, muscle recovery, fat metabolism, and overall vitality. Over-supplementation, however, can lead to joint pain, fluid retention, insulin resistance, abnormal facial or hand growth, and cardiovascular strain. Too much is also associated with certain cancers and can diminish athletic performance despite muscle growth.²
In adults, deficiencies can lead to fatigue, reduced muscle mass, increased abdominal fat, impaired exercise recovery, and reduced sexual interest. How does it become deficient? Usually from pituitary dysfunction, chronic poor sleep, untreated sleep apnea, head trauma, aging, or prior pituitary surgery or radiation.
GH works closely with other hormones, meaning disruptions here can ripple outward:
- Testosterone availability: GH supports pituitary signaling that helps regulate testosterone production.
- Energy and metabolism: GH interacts with thyroid hormones and insulin, and disruptions can lead to fatigue, altered blood sugar control, and reduced muscle performance.
- Vascular health: GH promotes nitric oxide production and supports healthy blood flow. Trouble here can impair erections even if testosterone levels are adequate.
- Body composition and fat distribution: GH works alongside cortisol and sex hormones to regulate fat and muscle mass. Interruptions in this network can shift fat to the abdomen, indirectly affecting testosterone-to-estrogen conversion and libido.
Every hormone has a specific job, but they also rely on one another to function. Sexual vitality is not governed by a single hormone; it’s regulated by a system. (And this is certainly not an exhaustive list of what’s at play.) Hence, changes in erections, libido, energy, or morning salutations aren’t just “performance issues.” Rather, they can be an indication of poorly regulated hormone traffic commonly caused by lifestyle interruptions and/or underlying health conditions.
Only 25% of men in the US who are prescribed treatment for Low-T undergo appropriate testing. I cannot stress enough how important it is to see the right doctor and undergo the right testing; other serious conditions can cause similar symptoms. Online clinics or pharmacies have their place and can seem convenient. But they can also overlook contributing factors such as sleep disorders, thyroid problems, adrenal dysfunction, medication interactions, or pituitary issues.
A full workup typically involves a detailed medical history, lab panels measuring total and free hormones, evaluation of thyroid, adrenal, and pituitary function, and sometimes imaging or specialized testing. Resulting therapies are targeted because they’re informed by your body’s unique chemical makeup.
Once you’ve been evaluated and discussed treatment options with Dr. Kapadia, it’s time to optimize your results. How, you might ask? Check out Part 2.
Dr. Kapadia is a distinguished member of a small, closely knit Reproductive Urology and Sexual Medicine community. He has published extensively in well-known medical journals and presented his research at both national and international meetings on male fertility and sexual medicine. His practice focuses on male fertility, sexual medicine, and hormone therapies, with an emphasis on personalized, system-wide care.
Resources:
- Valente, S., Marques, T., & Lima, S. Q. (2021). No evidence for prolactin’s involvement in the post-ejaculatory refractory period. Communications Biology, 4(10). https://doi.org/10.1038/s42003-020-01570-4.
- Australian Government Department of Health, Disability and Ageing Therapeutic Goods Administration. (2022, May 26). Too much of a good thing: the health risks of human growth hormone. Therapeutic Goods Administration (TGA). https://www.tga.gov.au/news/blog/too-much-good-thing-health-risks-human-growth-hormone.