Most varicoceles are not dangerous, but they can be serious depending on what they’re doing to your fertility and hormone levels over time. About 15% of all men have a varicocele, and many never know it. The condition becomes a concern when it causes pain, shrinks the affected testicle, or impairs sperm production. Whether yours needs attention depends on its size, your symptoms, and whether you’re trying to have children.
What a Varicocele Actually Does
A varicocele is a cluster of enlarged veins inside the scrotum, similar to varicose veins in the legs. Blood pools in these veins instead of draining efficiently, which raises the temperature around the testicle. That extra heat is the root of most problems: it can gradually damage the cells that produce sperm and testosterone.
The condition almost always develops on the left side due to the anatomy of how the left testicular vein connects to the kidney vein, though it can occur on both sides. Varicoceles tend to feel like a soft lump above the testicle, sometimes described as a “bag of worms.” They typically develop during puberty and may slowly worsen with age as the valves in the veins become less competent.
When It Causes Symptoms
Many varicoceles produce no symptoms at all. When they do, the pain is typically a dull, aching, or throbbing sensation in the testicle, scrotum, or groin. Sharp or stabbing pain is rare. The discomfort tends to worsen after standing for long periods, exercising, or straining, and it usually eases when you lie down. Some men describe it less as pain and more as a heavy, dragging feeling in the scrotum.
Pain alone doesn’t necessarily make a varicocele medically serious, but it can significantly affect quality of life. If the discomfort interferes with your daily activities or exercise, that’s a reasonable reason to discuss treatment options.
The Fertility Connection
This is where varicoceles shift from a nuisance to a genuine medical concern. Varicoceles are found in about 35% of men with primary infertility (those who have never fathered a child) and roughly 45% of men with secondary infertility (those who previously fathered a child but can no longer conceive). That’s a striking jump from the 15% rate in the general population.
The damage happens gradually. Pooled blood raises scrotal temperature, which disrupts the environment sperm need to develop properly. Over time, this leads to lower sperm counts, reduced motility (how well sperm swim), and abnormal sperm shape. The effects can be progressive, meaning a varicocele that isn’t causing fertility problems at 25 may contribute to them by 35.
Research also shows that varicoceles impair the cells responsible for producing testosterone. These cells gradually lose function through increased cell death and disruption of the chemical pathway that converts cholesterol into testosterone. Initially the effect may be limited to the affected testicle, but over time it can extend to both sides. Some of this damage may not be fully reversible, which is why earlier detection matters.
How Varicoceles Are Graded
Doctors classify varicoceles into three grades using a physical exam, which helps guide treatment decisions:
- Grade 1: Only detectable when you bear down (like you’re trying to have a bowel movement) while standing. This is the mildest form.
- Grade 2: Can be felt by your doctor while you’re standing at rest, without any straining.
- Grade 3: Large enough to be visible through the skin of the scrotum.
Higher grades are generally associated with more significant effects on fertility and testicular function, though even lower-grade varicoceles can impair sperm production in some men. An important point from the American Urological Association: varicoceles found only on imaging (not detectable by physical exam) are not considered clinically significant and do not warrant treatment.
Risks of Leaving It Untreated
For a man with a small, painless varicocele and no fertility concerns, leaving it alone is perfectly reasonable. Many men live their entire lives with a varicocele and never experience problems.
The risk of doing nothing is primarily relevant for men with larger varicoceles or abnormal semen results. Because the effects on both sperm production and testosterone levels are progressive, a varicocele that seems harmless now can cause more damage over the years. One well-documented consequence is testicular atrophy, where the affected testicle gradually shrinks. Research suggests that testosterone levels after varicocele repair, while improved, often don’t fully return to levels seen in men who never had a varicocele. This supports the idea that some testicular damage accumulates over time and becomes permanent.
Special Concerns for Teenagers
Varicoceles are common in adolescents and deserve closer monitoring during this age group because the testicles are still developing. The key measurement doctors track is the size difference between the two testicles. A volume difference of 15 to 20% or more, or a size gap greater than 2 cubic centimeters, has historically been the threshold for considering surgery.
More recent research has refined this. A combination of 15 to 20% size difference and high backward blood flow (measured on ultrasound) strongly predicts worsening asymmetry over time. Adolescents who meet these criteria generally do better with surgical repair than with observation alone. For teens who fall below these thresholds, regular monitoring every 6 to 12 months is the typical approach.
When Treatment Is Recommended
The American Urological Association recommends considering surgical repair when three conditions are met: the varicocele is palpable on physical exam, the couple is experiencing infertility, and semen analysis shows abnormal results. If all three are present, repair offers a meaningful chance of improvement.
Treatment is also reasonable for men with significant pain that hasn’t responded to conservative measures like supportive underwear or anti-inflammatory medications, and for adolescents with documented testicular shrinkage.
Situations where repair is not recommended include varicoceles detected only on imaging and cases where the man has no sperm at all (complete azoospermia), since there’s no strong evidence that repair restores sperm production in those men.
A new or sudden varicocele that doesn’t flatten when you lie down warrants further investigation. In rare cases, especially in older men, this can signal a mass in the abdomen or kidney area that’s compressing the testicular vein. Your doctor may recommend abdominal imaging to rule this out.
What Treatment Looks Like
The two main approaches are surgical ligation (tying off the enlarged veins) and percutaneous embolization (blocking the veins from the inside using a catheter threaded through a vein in the neck or groin). Both are outpatient procedures.
Surgical repair carries a small risk of hydrocele formation (fluid buildup around the testicle), which occurs in about 4% of cases, and a recurrence rate around 12%. Embolization has shown lower rates of both complications in comparative studies, though it isn’t always available or appropriate for every patient. Recovery from either procedure typically takes one to two weeks for light activity.
The results can be significant. A meta-analysis of 22 studies found that sperm concentration increased by an average of 12.3 million per milliliter after repair, with motility improving by about 10 percentage points. One prospective study showed even more dramatic gains: average sperm density rose from about 7 million to 17 million per milliliter, and progressive motility jumped from 9% to nearly 35%. Spontaneous pregnancy rates after repair reach roughly 37%. Testosterone levels also improve after surgery, though as noted, they may not fully normalize.
The Bottom Line on Seriousness
A varicocele sits on a spectrum. At one end, it’s an incidental finding that never causes a problem. At the other, it’s a progressive condition that can quietly erode fertility and testosterone production over years. The seriousness of yours depends on its grade, whether it’s affecting your semen quality or hormone levels, and whether it’s causing pain or testicular shrinkage. If you’ve been diagnosed with one and are concerned, a semen analysis and physical exam give your doctor enough information to tell you whether it needs treatment or just periodic monitoring.