Removing one testicle, a surgery called orchiectomy, leaves the remaining testicle to handle the body’s testosterone production and sperm supply on its own. Most men continue to produce enough hormone and retain the ability to father children, but the adjustment is not seamless for everyone. Hormonal shifts, changes in fertility, psychological effects, and a handful of less obvious physical consequences can follow the procedure, and the likelihood and severity of each depend on factors like age, the reason for surgery, and whether additional treatments such as chemotherapy are involved.
How One Testicle Compensates Hormonally
The remaining testicle typically ramps up its output after the other is removed. In younger patients especially, the solo testicle can grow measurably larger, a well-documented response called compensatory hypertrophy. The body’s hormonal feedback loop drives this: the brain senses less testosterone, signals harder, and the surviving testicle responds by increasing production.
That said, compensation is often incomplete. A study tracking hormonal changes after unilateral orchiectomy for testicular tumors found that the risk of clinically significant testosterone deficiency roughly doubled within a year of surgery. Before the operation, about one in five men already had low testosterone. One month after surgery, that proportion had risen to nearly two in five, and by one year it had climbed to roughly half of the group studied.
1PubMed Central. Dynamics of hormonal disorders following unilateral orchiectomy for a testicular tumorThe men in that study were being treated for cancer, which complicates the picture since many had abnormal hormone levels even before surgery. Still, the finding makes a clear point: losing one testicle does not guarantee that the other will fully pick up the slack. Symptoms of low testosterone can include fatigue, reduced muscle mass, lower sex drive, mood changes, and difficulty concentrating. When these symptoms are persistent and blood tests confirm low levels, testosterone replacement therapy becomes an option worth discussing with a doctor.
Fertility After Losing a Testicle
Sperm production takes a measurable hit after unilateral orchiectomy. In a study of men with testicular cancer, the median sperm concentration dropped from 17 million per milliliter before surgery to 7 million per milliliter afterward, and total sperm count fell as well. Sperm counts decreased in about 85% of the men studied, and roughly 9% became temporarily azoospermic, meaning no sperm were detectable at all.
2PubMed. Semen quality and reproductive hormones before and after orchiectomy in men with testicular cancerThese numbers deserve context. Many men with testicular cancer already have impaired sperm quality before surgery, possibly because the tumor itself disrupts normal testicular function. So the decline is not entirely caused by the surgery alone. Even so, the remaining testicle needs time to adapt, and for some men the recovery in sperm numbers is slow or partial.
Because of this, sperm banking before surgery is widely recommended. The logic is straightforward: freezing a sample costs relatively little compared to the peace of mind it offers, particularly for younger men who have not yet started families.
3PubMed Central. Cryopreservation of sperm should be offered to men with testicular cancerIf additional treatments follow surgery, the fertility picture becomes more serious. Radiotherapy and chemotherapy can damage the remaining testicle’s ability to produce sperm. In a study of men treated with post-operative radiation or chemotherapy for testicular cancer, adjuvant treatment caused sterility in 17 patients who had been previously fertile. When the remaining testicle atrophied after treatment, the sterility was irreversible.
4PubMed. The effect on fertility, libido and sexual function of post-operative radiotherapy and chemotherapy for cancer of the testicleSexual Function and Erectile Health
Physically, one testicle is enough to maintain erections and orgasms. The mechanics of arousal are driven by blood flow, nerve signaling, and testosterone, all of which can remain intact. But the research paints a more complicated real-world picture than the simple reassurance “everything should work fine.”
A systematic review and meta-analysis looking at erectile dysfunction among testicular cancer survivors found a pooled prevalence of about 35%.
5PubMed Central. Erectile dysfunction among testicular cancer survivors: A systematic review and meta-analysis That is higher than you might expect for a mostly young population, and the causes are tangled. Some of it is hormonal. Some relates to additional treatments beyond surgery. And a substantial portion appears to be psychological, rooted in anxiety, changed body image, or the stress of a cancer diagnosis.
A comparative study found that men who had undergone orchiectomy scored lower on measures of genital self-image, and also showed higher rates of erectile difficulty and premature ejaculation compared to controls.
6PubMed. Effects of orchiectomy on genital self-image, sexual function, and satisfaction: a comparative study The connection between self-image and sexual performance is well established in the broader literature, and orchiectomy seems to activate that link in many men. Feeling physically different can translate into performance anxiety, avoidance of intimacy, or reduced desire, even when the hormonal machinery is working adequately.
Research on testicular cancer survivors has also found that almost half experienced clinical symptoms of androgen deficiency, and those with symptoms had significantly lower scores for erectile function, orgasmic function, sexual desire, and overall sexual satisfaction compared to men without symptoms.
7Elsevier / PubMed Central. Androgen deficiency symptoms in testicular cancer survivors are associated with sexual problems but not with serum testosterone or therapy Interestingly, subjective symptoms of androgen deficiency did not always line up neatly with actual serum testosterone levels, suggesting that some sexual effects may be driven more by perception and psychology than by measurable hormone deficits.
Phantom Sensations
One side effect that rarely gets discussed is phantom testicular sensation, the feeling that the removed testicle is still there. In a study of 81 men who had undergone unilateral orchiectomy for testicular cancer, about 12% reported phantom sensations. Most of these appeared within the first few weeks after surgery. The sensations were painful in nine out of eleven cases, and in one patient the phantom pain was convincing enough to prompt surgical re-evaluation because doctors suspected a second tumor.
8PubMed. Phantom sensations after orchiectomy for testicular cancerThe encouraging part is that the phantoms tend to fade. In roughly two-thirds of affected patients, the sensations disappeared within 18 months. Three men in the study said the phantom feelings interfered with their sex life during the period they persisted. Phantom pain after amputation of any body part is a recognized neurological phenomenon, but because orchiectomy patients tend to be young and the topic is intimate, it often goes unmentioned in pre-surgical counseling. Knowing it can happen, and that it usually resolves, can spare a lot of unnecessary alarm.
Psychological Impact and Body Image
The psychological fallout from losing a testicle is underestimated in clinical settings. A large population-based follow-up of nearly 960 testicular cancer survivors found that about a third of men missed their removed testicle, and roughly a quarter reported uneasiness or shame about their body because of the surgery. These feelings were sometimes long-lasting, persisting years after treatment.
9PubMed. Feelings of loss and uneasiness or shame after removal of a testicle by orchidectomy: a population-based long-term follow-up of testicular cancer survivorsA study comparing men who had undergone orchiectomy for testicular torsion (not cancer) with men whose torsion was repaired without removing the testicle found strikingly different psychological outcomes. The orchiectomy group had significantly higher anxiety and stress scores, and 89% of those men reported body image dissatisfaction, all explicitly attributing it to losing the testicle.
10Journal of Pediatric Urology. Living with one: Mental health, body image and fertility concerns after orchiectomy for testicular torsion This study is useful because it isolates the effect of testicular loss itself, separate from the psychological weight of a cancer diagnosis.
A systematic review of mental health after orchiectomy noted that rigid adherence to traditional masculine norms, particularly around emotional expression and vulnerability, was associated with greater psychological distress in testicular cancer survivors. Men who felt unable to talk about their feelings or who tied their sense of masculinity tightly to physical completeness tended to fare worse.
11PubMed Central. Mental health after orchiectomy: Systematic review and strategic management Relationship status also plays a role. Research has found that being in a stable relationship acts as a protective factor, while single men are more predisposed to sexual dysfunction and related distress after treatment.
12PubMed Central. Sexual functioning of testicular cancer survivors and their partners – A review of literatureTesticular Prostheses
A silicone implant that mimics the size and weight of a natural testicle is available and can be placed during or after the orchiectomy. The satisfaction data on these implants is surprisingly positive overall, even when men have specific complaints about the details.
In one study, about 85% of patients reported looking normal in the genital region as “extremely important” or “important,” and 98% felt that being offered a prosthesis before surgery mattered. Overall satisfaction was high or very high in over 83% of recipients. However, more than half found the consistency “too firm,” about a quarter thought the size was too small, and roughly 30% felt the implant sat too high in the scrotum. Despite those specific gripes, 86% said they would choose the implant again if faced with the same decision.
13PubMed Central. Testicular prostheses in patients with testicular cancer – acceptance rate and patient satisfactionOther studies have reported similar patterns. A Portuguese survey found that overall satisfaction was rated excellent or good by nearly 98% of recipients, with 88% saying they would make the same choice again. The most common complaint there was also inappropriate texture.
14Revista Internacional de AndrologÃa. Satisfaction with testicular prosthesis: a Portuguese questionnaire-based study in testicular cancer survivors A third study reported 96% satisfaction and confirmed that the implant did not interfere with sexual function, though about a quarter of men still described it as too firm.
15PubMed Central. Testicular prostheses – impact on quality of life and sexual functionThe recurring theme is that prostheses are good at restoring the visual appearance of a normal scrotum but imperfect at mimicking the natural feel. Current implants are made of solid silicone, which is firmer than testicular tissue. For many men, the cosmetic normalization is enough to reduce body image distress. Others find the difference in texture noticeable and distracting. The fact that roughly a third of men in one study felt pre-operative counseling about the implant was too short or insufficient suggests this is an area where better communication from surgeons could help men set realistic expectations.
Bone Health Risks
Testosterone plays a role in maintaining bone density, so losing a source of it raises a reasonable question about long-term skeletal health. The human evidence here is thinner than for the other effects discussed above, but animal research gives a clear signal worth paying attention to.
In rat studies, orchiectomy produced a significant decline in femoral bone mineral density within a few months. The loss of bone density was measurable and consistent, appearing by eight weeks after surgery and persisting at ten weeks.
16PubMed Central. Bone Mineral Density Changes after Orchiectomy using a Scrotal Approach in Rats A separate study in aged rats confirmed that orchiectomy caused marked trabecular bone damage, but also showed that testosterone replacement restored bone strength to levels similar to those in non-operated animals.
17PubMed. Physiological testosterone replacement effects on male aged rats with orchiectomy-induced osteoporosis in advanced stage: a tomographic and biomechanical pilot studyRats in these studies had both testicles removed, which creates a more extreme hormonal deficit than unilateral orchiectomy in a human. A man with one functioning testicle is still producing testosterone, so the bone effects would be less dramatic. But if that man’s remaining testicle under-produces, if he is older, or if he also undergoes treatments that suppress testosterone, the risk of bone thinning is real and worth monitoring with periodic bone density scans.
Cardiovascular and Metabolic Changes
Testicular cancer survivors as a whole face elevated cardiovascular risk, but teasing apart the contribution of the surgery from the contribution of chemotherapy is difficult. A large study tracking cardiovascular disease in testicular cancer survivors found that compared to men treated with orchiectomy alone, those who also received cisplatin-based chemotherapy had roughly double the risk of cardiovascular disease. Among survivors who underwent clinical evaluation at a median age of 51, 86% had abnormal cholesterol levels, half had high blood pressure, and about a third met criteria for metabolic syndrome, regardless of which treatment they had received.
18PubMed Central. Cardiovascular Disease in Testicular Cancer Survivors: Identification of Risk Factors and Impact on Quality of LifeThe high prevalence of metabolic syndrome in that group is striking. These are men who were diagnosed young and typically considered otherwise healthy. Some of this metabolic risk may be tied to subtle, long-term testosterone insufficiency after losing a testicle, since low testosterone is independently associated with insulin resistance and unfavorable cholesterol profiles. But chemotherapy, radiation, and the stress of a cancer experience all contribute too, so the surgery alone is unlikely to be the main driver for most men. What matters practically is that anyone who has had a testicle removed should not assume their cardiovascular risk profile is unchanged, especially as they enter middle age.
When the Reason for Surgery Is Not Cancer
Most of the research on orchiectomy focuses on testicular cancer patients, but testicles are also removed after severe torsion (when blood supply is cut off and the testicle dies), after traumatic injury, and occasionally for other medical reasons. The physical side effects are largely the same regardless of why the surgery happened. You still lose half your testosterone production capacity and half your sperm-producing tissue.
Psychological effects, however, can differ depending on context. Men who lose a testicle to torsion, particularly younger men and adolescents, may experience pronounced body image distress because the loss feels random rather than tied to a life-threatening illness. As noted earlier, a study focused specifically on torsion-related orchiectomy found extremely high rates of body dissatisfaction. Cancer patients, while dealing with their own substantial psychological burden, sometimes frame the surgery as part of saving their life, which can provide a narrative that helps with coping. Men who lose a testicle to trauma or torsion do not always have that framework available.
Protecting the Remaining Testicle
Once you are down to one testicle, that remaining organ becomes considerably more important. An injury or disease affecting the sole remaining testicle would mean complete loss of testicular function, leaving you dependent on lifelong testosterone replacement and unable to produce sperm naturally. Wearing a protective cup during contact sports or activities with a risk of groin impact shifts from optional to genuinely prudent. This is not about being overly cautious; it is about the simple math that you no longer have a backup.
You should also be diligent about self-examination of the remaining testicle. Men who have had testicular cancer in one testicle have a slightly elevated risk of developing cancer in the other, although the absolute risk remains low. Catching any new issue early matters more when you only have one.
Regular follow-up with a doctor for hormone monitoring is also worthwhile. As discussed, testosterone deficiency can develop gradually after orchiectomy, and the symptoms can be vague enough to dismiss as aging or stress. A periodic blood test is a simple way to catch a decline before it causes significant quality-of-life problems. If levels drop below normal and symptoms are present, replacement therapy can address most of the hormonal side effects effectively.