Low testosterone can affect fertility through symptoms like low sperm count, reduced semen volume, erectile dysfunction, changes in testicular size or feel, loss of body hair, breast tissue development, and fatigue that undermines the healthy habits sperm quality depends on.
If you're trying to conceive and something feels off, you might wonder whether your hormones are playing a role. Low testosterone gets a lot of attention for its effects on libido and muscle mass, but the connection to fertility is more specific—and often misunderstood.
Here's what the research actually shows about how low testosterone shows up when fertility is on the line.
The direct symptom: low sperm count
This is the most straightforward link between low testosterone and fertility. Testosterone is required for sperm production in the testes. When levels drop below a certain threshold, the machinery slows down.
A 2015 study in Human Reproduction Update found that men with low testosterone were significantly more likely to have low sperm counts. The relationship isn't perfectly linear—some men with low T still produce adequate sperm—but it's consistent enough that fertility specialists check testosterone as part of a standard workup.
The symptom you'd notice: not conceiving after a year of trying. There's no internal sensation that tells you your count is low. That's why testing matters.
Reduced semen volume
Testosterone helps the seminal vesicles and prostate produce the fluid that carries sperm. When testosterone drops, semen volume often drops with it.
This is something you can observe. If your ejaculate volume is noticeably smaller than it used to be, it's worth mentioning to a doctor. Normal volume ranges from 1.5 to 5 milliliters per ejaculation. Consistently below that can indicate a hormonal issue.
One study in Fertility and Sterility (2013) reported that men with low testosterone had average semen volumes about 30% lower than men with normal levels. That reduction alone doesn't prevent pregnancy, but combined with other factors, it can stack the odds against you.
Erectile dysfunction and libido changes
These are the symptoms most men associate with low testosterone, and they do affect fertility—just indirectly.
If erections are inconsistent or libido has dropped, you're having less sex. Less sex means fewer attempts at conception. That sounds obvious, but it's worth stating because many men assume fertility is only about sperm quality. The behavioral component matters too.
Research from the European Male Ageing Study (2014) found that men with total testosterone below 300 ng/dL were roughly twice as likely to report erectile dysfunction compared to men with normal levels. The same study linked low T to reduced sexual thoughts and morning erections.
The practical takeaway: if your sex drive has taken a noticeable hit and you're trying to conceive, testosterone testing should be on your list.
Changes in testicular size or feel
Testosterone is produced in the testes, and the same cells that make testosterone also support sperm production. When testosterone drops due to a testicular issue, the testes themselves can change.
Some men notice their testicles feel softer or smaller than they used to. This isn't something most guys check regularly, but if you're already concerned about fertility, it's worth paying attention to.
Varicoceles—enlarged veins in the scrotum—can cause both low testosterone and poor sperm quality. A 2017 review in Asian Journal of Andrology estimated that varicoceles are present in about 15% of men overall and up to 40% of men being evaluated for infertility. The condition is often accompanied by a dull ache or a feeling of heaviness, but some men have no symptoms beyond the physical change.
Loss of body hair and breast tissue development
Testosterone converts to DHT, the hormone that drives facial and body hair growth. When testosterone drops, men sometimes notice they're shaving less often or that chest and leg hair has thinned.
At the same time, the ratio of testosterone to estrogen can shift. When testosterone falls and estrogen stays the same or rises, some men develop gynecomastia—glandular breast tissue. This isn't fat from weight gain; it's firm tissue behind the nipple.
Both of these symptoms point to a hormonal imbalance that could affect fertility. A 2018 study in The Journal of Clinical Endocrinology & Metabolism found that men with gynecomastia had significantly lower testosterone-to-estrogen ratios than controls, and about a third had abnormal semen parameters.
Fatigue and mood changes that affect consistency
This is the symptom that's easy to dismiss. Low testosterone doesn't always hit you like a truck. Sometimes it shows up as a slow slide: you're more tired than you used to be, you've lost motivation at the gym, your mood is flatter.
How does this connect to fertility? Through consistency. Fertility optimization—sleep, nutrition, exercise, stress management—requires energy and discipline. When testosterone is low, maintaining those habits gets harder. You skip workouts. You eat worse. You sleep less. Each of those choices nudges sperm quality down.
A 2020 meta-analysis in Human Reproduction found that men with depression or chronic stress had lower sperm counts and motility. Low testosterone contributes to both conditions. It's a feedback loop.
What this means for you
If you're experiencing any combination of these symptoms and you've been trying to conceive without success for six to twelve months, a testosterone test is reasonable. A simple blood draw measures total testosterone, free testosterone, LH, FSH, and estradiol. That panel tells you—and your doctor—whether hormones are part of the picture.
Here's the nuance that most online articles miss: low testosterone alone doesn't automatically mean you're infertile. Some men with low T have normal sperm counts. Some men with high T have low counts. The relationship is mediated by how the testes respond to signals from the pituitary gland.
That's why fertility specialists look at the full picture—not just testosterone, but FSH and LH, which tell them whether the brain is properly signaling the testes. If FSH is high and testosterone is low, the testes aren't responding. If both are low, the problem might be in the pituitary.
One caveat: If you're using sauna or heat therapy and concerned about fertility, testosterone isn't the main variable. Heat affects sperm production directly—sperm cells are temperature-sensitive. Testosterone production is more resilient to heat. The two are related but not identical.
What you can do
If symptoms are present and a test confirms low testosterone, the next step depends on the cause. Lifestyle factors—poor sleep, high stress, low body fat or excessive body fat, alcohol overuse—can suppress testosterone. Addressing those often improves both testosterone and fertility markers.
If the cause is medical, your doctor will guide you. The goal for fertility is usually to raise testosterone enough to support sperm production without suppressing the brain's signaling system. That's a balancing act that requires professional oversight.
Talk to your doctor. Fertility is complex, and individual situations vary. No blog post replaces a conversation with someone who has your labs in front of them.
Frequently asked questions
Can low testosterone cause low sperm count?
Yes, testosterone is required for sperm production in the testes, and when levels drop below a certain threshold the process slows down. A study in Human Reproduction Update found that men with low testosterone were significantly more likely to have low sperm counts. The relationship isn't perfectly linear, though, since some men with low testosterone still produce adequate sperm.
Does low testosterone affect semen volume?
It can. Testosterone helps the seminal vesicles and prostate produce the fluid that carries sperm, so when testosterone drops, semen volume often follows. A study in Fertility and Sterility reported that men with low testosterone had average semen volumes about 30% lower than men with normal levels. Normal volume ranges from 1.5 to 5 milliliters per ejaculation, and consistently falling below that range is worth discussing with a doctor.
What is gynecomastia and how does it relate to low testosterone and fertility?
Gynecomastia is the development of firm glandular breast tissue behind the nipple, caused by a shift in the ratio of testosterone to estrogen. A 2018 study in The Journal of Clinical Endocrinology and Metabolism found that men with gynecomastia had significantly lower testosterone-to-estrogen ratios than controls, and about a third had abnormal semen parameters. It's a sign of hormonal imbalance that can be relevant to fertility.
If I have low testosterone does that mean I'm infertile?
Not necessarily. Low testosterone alone doesn't automatically mean you're infertile, since some men with low testosterone have normal sperm counts and some men with high testosterone have low counts. Fertility specialists look at the full hormonal picture, including FSH and LH, to understand whether the brain is properly signaling the testes. A blood panel measuring total testosterone, free testosterone, LH, FSH, and estradiol gives a clearer picture than testosterone alone.