Losing a testicle, whether to cancer, torsion, trauma, or another cause, does not shut down your hormonal system or end your fertility. The remaining testicle typically ramps up its output to compensate, and most men continue producing enough testosterone and sperm to function. But “compensates” does not mean “perfectly replaces,” and the downstream effects on hormones, fertility, sexual function, body image, and even phantom pain are more varied and persistent than many people expect.
How the Remaining Testicle Picks Up the Slack
Each testicle has two main jobs: producing testosterone (handled by Leydig cells) and producing sperm (handled by the seminiferous tubules). When one is removed, the brain detects the dip in testosterone and sends stronger chemical signals to the surviving testicle, telling it to work harder. In many men this works well enough that testosterone levels stay within the normal range. But the compensation is not always complete. Research tracking men after removal of a testicle for a tumor found that testosterone and estradiol levels decreased over the observation period, while luteinizing hormone (LH) and follicle-stimulating hormone (FSH), the brain signals pushing the remaining testicle to produce more, rose significantly.
1PubMed Central. Dynamics of hormonal disorders following unilateral orchiectomy for a testicular tumorThat pattern of rising brain signals plus borderline testosterone is sometimes called compensated hypogonadism: the testicle is managing to keep testosterone in the low-normal zone, but only because the brain is pushing it hard. A study comparing men with a single testicle to men with both found that about 28% of the single-testicle group had this compensated state, compared to roughly 8% of the comparison group.
2PubMed. Evaluation of Reproductive Parameters in Men with Solitary TestisEven among men managed by surgery alone with no chemotherapy or radiation, roughly 11% had subnormally low testosterone and over 40% had elevated FSH, a sign that sperm production was under strain.
3British Journal of Cancer. Fertility, gonadal and sexual function in survivors of testicular cancerFor most men, these shifts do not produce dramatic symptoms. You are unlikely to suddenly lose muscle mass or develop hot flashes from losing one testicle. But some men notice subtler changes: slightly lower energy, mild shifts in mood, or a dip in libido. When testosterone does drop below a clinically meaningful threshold, testosterone replacement therapy is an option, though the decision is more complicated for men whose levels are borderline rather than clearly deficient.
4PubMed. Effect of Testosterone Replacement Therapy on Quality of Life and Sexual Function in Testicular Cancer Survivors With Mild Leydig Cell Insufficiency: Results From a Randomized Double-blind TrialWhat Happens to Fertility
Sperm production takes a measurable hit. The numbers vary depending on when the sample is collected and whether the testicle was removed for cancer, but the direction is consistent: total sperm count, concentration, and motility all tend to drop after surgery. A two-center study found that median total sperm count fell from about 57 million before surgery to 13 million afterward, and the rate of producing zero sperm tripled from around 5% to nearly 15%.
5PubMed Central. Preoperative semen quality is superior to the quality shortly after orchiectomy in patients with testicular germ cell tumour – a retrospective study from two centres in GermanyAnother study tracking individual patients before and after surgery confirmed a decline in sperm concentration and motility, though total sperm count did not reach statistical significance for every metric in that smaller sample.
6PubMed. Cryopreservation of Spermatozoa Prior and Post-Orchiectomy in Patients With Testicular Germ Cell Cancer-Does the Timing Matter?The practical takeaway is that many men with one testicle can still father children naturally, but the margin for error is thinner. If you are facing surgery and future fatherhood matters to you, banking sperm beforehand is strongly recommended. Sperm quality is consistently better in pre-surgery samples. Interestingly, though total count and motility drop after the testicle is removed, one study found that DNA fragmentation in the sperm actually improved once the tumor was gone, suggesting the cancerous testicle had been sending out damaged sperm before it was removed.
7PubMed Central. Semen Cryopreservation in Testicular Cancer: Before or After Orchidectomy?For men who did not bank sperm before surgery, it is not all bad news. The remaining testicle can often produce enough viable sperm for conception, especially with time. But if additional treatment like chemotherapy is planned, the fertility window may narrow further, making early cryopreservation all the more important.
Sexual Function After Losing a Testicle
This is the question many men worry about most but feel least comfortable asking. The honest answer is that losing a testicle does affect sexual function for a meaningful number of men, but probably not for the reasons you would guess. The hormonal contribution is surprisingly small. The bigger factors appear to be the surgery itself, the psychological impact of a cancer diagnosis, and follow-up treatments.
A systematic review pooling data across multiple studies found that roughly 35% of testicular cancer survivors reported erectile dysfunction.
8PubMed Central. Erectile dysfunction among testicular cancer survivors: A systematic review and meta-analysisA long-term follow-up study found that about a quarter of survivors had erectile difficulties at a mean follow-up of roughly seven years, with about 11% experiencing severe dysfunction. Recovery took time: the median was about five years regardless of whether men had received chemotherapy or other post-surgical treatment. Radiation therapy was the strongest predictor of not recovering normal erections, while chemotherapy alone did not significantly impair recovery.
9PubMed Central. Long-term recovery of normal sexual function in testicular cancer survivorsOne finding that stands out: researchers consistently fail to find a clear link between testosterone levels and sexual function scores in these men. A study comparing testicular cancer survivors to matched controls found persistently lower scores on desire, satisfaction, and erection quality, but these scores did not correlate with whether a man’s testosterone was low or normal. The authors suggest the surgical experience itself and the psychological weight of a cancer diagnosis may be doing most of the damage.
10Frontiers in Endocrinology. Long-Term Follow Up of the Erectile Function of Testicular Cancer SurvivorsThat disconnect matters because it means simply correcting testosterone levels may not fix the problem. Men who are struggling sexually after losing a testicle often benefit from psychological support or couples therapy as much as, or more than, hormone replacement.
Phantom Testis Syndrome
Just as people who lose a limb sometimes feel phantom sensations where the limb used to be, men who lose a testicle can experience phantom testis syndrome. This is more common than most people realize. In a survey of 238 men who had a testicle removed, over half reported some kind of phantom experience. A quarter reported phantom pain, about 16% had non-painful phantom sensations like tingling or pressure, and 12% described vivid phantom experiences that researchers classified as hallucinations of the missing testicle.
11PubMed. Phantom testis syndrome: prevalence, phenomenology and putative mechanismsMen who had pain in the affected testicle before surgery were more likely to experience phantom symptoms afterward, which fits with what we know about phantom limb pain: the brain’s map of the body persists even after the structure it represents is gone, and pain pathways that were active before removal tend to keep firing. Most phantom testis sensations fade over time, but for some men they become chronic. A comparison study found that about 11% of men who had a testicle removed for cancer reported chronic phantom pain, defined as persistent pain lasting well beyond the expected healing period.
12PubMed Central. Chronic phantom pain as a rare phenomenon after gender-affirming surgery: a systematic comparison studyIf you are experiencing ongoing pain or strange sensations in the area where your testicle used to be, it is worth knowing that this is a recognized condition with a name, not something you are imagining. Treatment options borrowed from phantom limb management, including nerve blocks and certain medications used for neuropathic pain, can help.
Body Image, Shame, and the Emotional Toll
The psychological effects of losing a testicle are poorly discussed but well documented. In a long-term population study of testicular cancer survivors, about a third said they missed their removed testicle, and roughly a quarter reported feelings of uneasiness or shame about their body.
13PubMed. Feelings of loss and uneasiness or shame after removal of a testicle by orchidectomy: a population-based long-term follow-up of testicular cancer survivorsAmong younger men who lost a testicle to testicular torsion rather than cancer, the numbers are starker. In one study, 89% of patients who had undergone the surgery reported dissatisfaction with their body image, and every one of them attributed it directly to the missing testicle. Their most frequent concern was fear of future infertility, which often persisted even when doctors reassured them that one testicle could be enough.
14Journal of Pediatric Urology. Living with one: Mental health, body image and fertility concerns after orchiectomy for testicular torsionA systematic review examining mental health after testicle removal found that both hormonal and non-hormonal pathways contribute to anxiety, depression, and cognitive complaints. Men who undergo bilateral removal for prostate cancer experience the most severe metabolic and psychological effects, including changes in body fat distribution and insulin resistance that can compound mood disturbances. But even losing one testicle produces measurable emotional effects that linger for years in some men.
15PubMed Central. Mental health after orchiectomy: Systematic review and strategic managementTesticular Prostheses
A silicone testicular implant is an option during or after surgery. The prosthesis sits in the scrotum and is designed to look and feel like a natural testicle. It has no hormonal or reproductive function; it is entirely cosmetic. But cosmetic does not mean trivial when body image distress is as common as the evidence shows.
Satisfaction rates are generally high. In one study, over 83% of patients rated their satisfaction as high or very high, and 86% said they would choose the prosthesis again.
16PubMed Central. Testicular prostheses in patients with testicular cancer – acceptance rate and patient satisfactionThat said, complaints are common enough to set realistic expectations. About half of implant recipients felt the prosthesis was too firm, roughly a quarter thought it was too small, and about 30% felt it sat too high in the scrotum.
A separate study focusing on decision regret found that men who received a prosthesis at the same time as their testicle was removed reported less regret, better body image, and fewer complaints from partners than men who did not get one. Having the implant placed at the same surgery was associated with roughly 60% lower odds of decision regret compared to going without.
17PubMed. Decision Regret About Testicular Prosthesis After Radical Orchiectomy: Real-life Data to Improve Preoperative Patient CounselingOne finding from the torsion study is worth flagging here: receiving a prosthesis improved men’s self-perceived body image, but it did not significantly reduce anxiety or stress.
14Journal of Pediatric Urology. Living with one: Mental health, body image and fertility concerns after orchiectomy for testicular torsionA prosthesis can address the cosmetic concern, but the deeper emotional effects of losing a testicle may need their own treatment.
When Cancer Treatment Adds to the Impact
If surgery is the only treatment you need, the effects described above are roughly the extent of the physical changes. But testicular cancer often requires follow-up chemotherapy, radiation, or retroperitoneal lymph node dissection, and each adds its own toll.
Chemotherapy, particularly cisplatin-based regimens, temporarily halts sperm production in most men. At standard doses, recovery usually happens within a couple of years, though higher cumulative doses can cause permanent damage. Alkylating agents used for certain blood cancers are especially harsh on the sperm-producing cells. Radiation above certain thresholds can also destroy sperm cells, and Leydig cells, the testosterone producers, become vulnerable at still higher doses.
18PubMed. Testicular function following chemo-radiotherapyAn older but influential study tracking men with advanced testicular cancer through surgery plus chemotherapy found that testosterone levels stayed at the low end of normal for two years after treatment ended, with LH and FSH remaining elevated. Before treatment, 72% of these men already had abnormal sperm counts; two years after finishing chemotherapy, 48% still had low counts, and the proportion with zero sperm had actually increased from 4% to 28%. Some men also lost the ability to ejaculate forward after lymph node surgery, a complication that is now less common with modern nerve-sparing techniques but still occurs.
19PubMed. Gonadal function after surgery and chemotherapy in men with stage II and III nonseminomatous testicular tumorsProtecting the Remaining Testicle
Once you are down to a single testicle, that remaining one carries all the reproductive and hormonal responsibility. Protecting it becomes a practical concern.
If the original loss was due to testicular cancer, there is a real but small risk of cancer developing in the other testicle. The prevalence of bilateral testicular cancer, where a tumor appears in the opposite testicle at a later date, is estimated at roughly 1% to 5%.
20PubMed Central. Metachronous Testicular Cancer After Orchiectomy: A Rare CaseA large follow-up study of nearly 2,000 testicular cancer patients found that the relative risk of developing cancer in the opposite testicle was about 36 times higher than the general population’s baseline risk for testicular cancer. Elevated risks were also seen for certain gastrointestinal cancers and leukemia, likely related to radiation and chemotherapy exposure rather than the orchiectomy itself.
21PubMed. Second cancer risk following testicular cancer: a follow-up study of 1,909 patientsRegular self-exams of the remaining testicle and follow-up imaging per your oncologist’s schedule are standard practice. If the cause was trauma or torsion rather than cancer, the contralateral cancer risk does not apply in the same way, but general testicular health monitoring is still worth maintaining. Athletic cups and other protective gear become less about caution and more about necessity when you are down to one.
Men who lost a testicle to torsion should also know that some of the risk factors for torsion, such as a bell-clapper deformity where the testicle hangs more freely inside the scrotum, can be bilateral. If the anatomy that caused the torsion exists on both sides, a surgeon may recommend a preventive procedure to anchor the remaining testicle in place.
Metabolic Changes and the Bilateral Distinction
For men who lose both testicles, the story is fundamentally different. Bilateral orchiectomy, most commonly performed as part of treatment for advanced prostate cancer, eliminates the body’s primary testosterone source. The effects are immediate and dramatic: hot flashes, rapid loss of muscle mass, increased body fat, bone density loss, and mood changes that can include depression, anxiety, and cognitive fog. Metabolic disturbances including shifts in insulin sensitivity and lipid levels are consistently reported.
15PubMed Central. Mental health after orchiectomy: Systematic review and strategic managementAnimal research has explored the metabolic consequences in controlled settings. In rat models, bilateral removal reduced body weight gain, lowered certain blood fats like triglycerides, and increased blood pressure.
22Open Journal of Biological Sciences. Morphofunctional and Metabolic Alterations after OrchiectomyTestosterone replacement therapy is standard care after bilateral removal and addresses most of the acute symptoms. For men who lost a single testicle and are managing with borderline hormone levels, the decision about replacement therapy is less clear-cut. The benefits of supplementing mildly low testosterone have to be weighed against the long-term risks and monitoring requirements of hormone therapy, and clinical trials in this specific group are still limited.
4PubMed. Effect of Testosterone Replacement Therapy on Quality of Life and Sexual Function in Testicular Cancer Survivors With Mild Leydig Cell Insufficiency: Results From a Randomized Double-blind TrialThe distinction matters because popular accounts of “what happens when you lose a testicle” often blend unilateral and bilateral outcomes together. If you lost one testicle, you are not facing the severe hormonal cliff that comes with losing both. Your body has a backup system, and for most men it works reasonably well, even if it is not perfect.