5 hormones & biomarkers for men's health & fertility—what they are & why they all matter

Published July 12, 2024

Hormones control everything from your muscles and bones to mood and sex drive. They're not just essential for health—they're essential for life.¹

When it comes to men’s health, testosterone often gets all the attention. But it’s just 1 part of a larger, connected system. Overlooked, yet critical: estradiol, prolactin, sex hormone-binding globulin, and albumin are also key players. So, while it might appear to be a one-hormone show, it takes a team to power men's health—and every player counts.

1. Testosterone
2. Estradiol
3. Prolactin
4. Sex hormone-binding globulin
5. Albumin

What’s the big deal about hormones?

Your body is a complex machine, and hormones are its chemical controllers. They travel through your bloodstream, delivering messages to certain cells. Once there, they tell these cells what to do and when to do it. Hormones don't simply influence certain body functions—they control them.¹

What’s a hormonal imbalance? How does it happen?

A hormonal imbalance happens when your body has too much or too little of 1 or more hormones. Hormones control everything from your muscles and bones to mood and sex drive. So, even small changes can affect your health in big ways. Hormonal imbalances can sometimes lead to health conditions that require treatment.¹

Some common hormone-related conditions include¹:

• Infertility
• Thyroid disorders
• Diabetes
• Obesity
• Hormonal acne
• Male hypogonadism (hy-po-go-nad-ism): low testosterone

If you’re feeling off—don’t ignore it. Understanding your hormones is a great step, but it's not the whole picture. If your hormones need some attention, teaming up with a doctor is key for diagnosis or treatment. They're the experts who can guide you back to feeling like yourself again.

What are the symptoms of sex hormone imbalance in men? What should I look for?

Our bodies rely on a delicate balance of hormones to function properly. When that balance gets thrown off, it can cause a variety of symptoms. For men, low testosterone levels are more common than high levels. Symptoms to look for include[¹⁻³]:

Symptoms of LOW testosterone: 

• Less interest in sex
• Erectile dysfunction (difficulty getting or keeping an erection)
• Decrease in testicle size
• Low sperm count
• Infertility
• Gynecomastia (guy-ne-ko-mas-tee-uh): enlarged male breast tissue
• Decreased muscle mass and strength
• Bone weakness
• Loss of body hair
• Weight gain
• Hot flashes (sudden feelings of intense heat, sweating, and discomfort)
• Feeling tired
• Shifts in energy levels
• Trouble sleeping
• Issues with memory or focus
• Feeling down, depressed, or irritable

Symptoms of HIGH testosterone: 

• Enlarged prostate
• Difficulty urinating
• Erectile dysfunction
• Decrease in testicle size
• Low sperm count
• Increased muscle mass
• High blood pressure
• High cholesterol
• Heart or liver problems
• Headaches
• Acne
• Weight gain
• Fluid retention
• Swelling of legs and feet
• Trouble sleeping
• Acting in ways you normally wouldn’t (irritable, aggressive)
• Mood swings

1. Testosterone

Testosterone, the main male sex hormone, guides important changes throughout a man’s life. Though it’s mostly made in the testicles, the process starts in the brain. It begins when the hypothalamus (hy-po-thal-uh-muhs) releases a hormone that signals the pituitary gland. This pea-sized gland then responds by releasing another hormone that tells the testicles: it’s time to make testosterone. Once produced, testosterone travels through the bloodstream to support many bodily functions.²⁻³

The role of testosterone in men's health & fertility

Your body relies on testosterone for many functions, including[²⁻³]:

• Bone growth and strength
• Muscle growth and strength
• Balanced mood
• Red blood cell production
• Sex drive
• Sperm production
• Overall health and well-being

2. Estradiol

Estrogen is often associated with women and testosterone with men. But the truth is, both hormones are important for all human bodies. Men produce and need estrogen too, just in much smaller amounts. Their bodies make it by converting a small amount of testosterone into estradiol (eh-struh-dial), the main form of estrogen. This conversion takes place in the testicles, adrenal glands, and fat cells—all thanks to an enzyme called aromatase (uh-roh-muh-tays).⁴

The role of estradiol in men's health & fertility

Small amounts of estradiol help support sex drive, erectile function, sperm creation, and testicular function. But its influence doesn’t stop there. Estradiol regulates mood, strengthens bones, manages cholesterol, and even supports a healthy heart.⁴

As men age, they often make less testosterone, and so they make less estradiol.⁴ This means certain changes blamed on low testosterone might actually be due to low estradiol.⁵ Too much or too little estradiol in men can lead to infertility, erectile dysfunction, depression, bone loss, low sex drive, or increased waist size.⁴

3. Prolactin

Prolactin is a hormone primarily produced by your pituitary gland. In men, prolactin plays an important role in overall reproductive function.⁶

The role of prolactin in men's health & fertility

Our bodies have different ways of managing hormone levels. Your body controls prolactin production using 2 hormones⁶:

1. Dopamine, to slow it down
2. Estradiol, to speed it up

When this balance is disrupted, it can cause a range of issues. Prolactin levels are typically low in men. When levels become too high, it's called hyperprolactinemia (hyper-pro-lack-tuh-nee-mee-uh). Too much prolactin in males can cause[⁶⁻⁷]:

• Low testosterone levels
• Headaches
• Vision changes
• Decreased sex drive
• Erectile dysfunction
• Infertility
• Gynecomastia
• Bone loss

4. Sex hormone-binding globulin

Sex hormone-binding globulin, or SHBG, is a protein mostly made by your liver. Its name reflects its function: a globulin (type of protein) that binds to sex hormones in the bloodstream.⁸

The role of SHBG in men's health & fertility

SHBG controls how much active sex hormone is available in your body. When SHBG binds (attaches) to testosterone and estradiol, your body can't use them. Only "free" hormones (not those bound to SHBG) are active. This balance is important because hormones control many things, like energy, fertility, and mood.⁸ Hormone regulation is a crucial job. Our body's balance relies on each hormone doing its job at the right time. If all hormones were active at once, this balance would be disrupted—impacting overall health and quality of life.¹

When SHBG is low, more hormones are free and active. When SHBG is high, more hormones are bound and inactive. Here's how unbalanced SHBG can throw testosterone levels off and cause symptoms⁸:

⬇️ Low SHBG = ⬆️ More free testosterone = ⬆️ Symptoms of high testosterone

⬆️ High SHBG = ⬇️ Less free testosterone = ⬇️ Symptoms of low testosterone

5. Albumin

Albumin, the most abundant protein in blood plasma, is produced by your liver. It plays multiple important roles, including transporting and regulating hormones.⁹ Albumin is yet another way the body gets certain hormones to the right places at the right levels.

The role of albumin in men's health & fertility

Testosterone travels in your bloodstream in 2 ways: free or bound to proteins. Most testosterone attaches to either albumin or SHBG, while a small portion remains ready for use.⁹ Both proteins bind to and transport testosterone and estradiol.⁸ But albumin has a looser grip on testosterone compared to SHBG. This allows testosterone to easily detach from albumin and become useable by the body.¹⁰ 

The amount of SHBG and albumin in your blood can help determine the amount of free and bioavailable testosterone in your body. Bioavailable testosterone includes 2 forms: free testosterone and testosterone loosely attached to albumin. These forms are considered "bioavailable" because they're ready for your body to use.¹⁰

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