One testicle bigger than the other: Causes, risks, and self-exams

Let’s get this out of the way first: it’s very common for one testicle to be a little bigger
or hang lower than the other. Bodies are not perfectly symmetrical, and testicles are no exception. Still,
if you’ve looked down, noticed a size difference, and immediately imagined the worst-case scenario, you’re
definitely not alone.

The important thing is knowing where “normal” ends and “please call a doctor” begins. Understanding what can
cause one testicle to look or feel larger, what warning signs to watch for, and how to do a proper
testicular self-exam can help you catch serious problems early and lower your anxiety at the same time.

Is it normal if one testicle is bigger?

In many people, the left testicle hangs a bit lower and can be slightly larger than the right. A small size
difference or a testicle sitting lower is usually normal anatomy. Think of it like having
one foot half a size bigger than the other or one eyebrow that refuses to cooperate—annoying, but not
dangerous.

A healthy testicle typically feels:

• Firm but not rock-hard
• Smooth on the surface (no obvious lumps or bumps)
• Free of sharp or severe pain

What’s not normal is a testicle that suddenly gets bigger, becomes hard, very tender, or develops a
noticeable lump, especially if this change happens over days or weeks instead of being the way your body has
always been. That’s your cue to stop guessing and talk with a healthcare professional.

Common causes of one testicle being bigger than the other

A size difference can come from harmless reasons, but sometimes it signals an underlying medical condition.
Here are some of the more common causes, from relatively mild to genuinely serious.

1. Normal anatomy and mild natural asymmetry

If one testicle has always been slightly bigger and there are no other symptoms (no pain, no lump, no
heaviness, no change in size over time), it’s likely just your natural anatomy. Many people discover this
for the first time only after they start doing self-exams.

2. Varicocele (enlarged veins in the scrotum)

A varicocele is like having varicose veins in your scrotum. The veins that drain blood from
the testicle become enlarged and twisty. This often occurs on the left side and may cause that testicle to
look larger or sit lower.

Common features of a varicocele include:

• A feeling of heaviness or dull ache in the scrotum, especially after standing a long time
• A “bag of worms” sensation when you feel the veins above the testicle
• Size difference that becomes more obvious over time

Varicoceles are common and often harmless but can sometimes affect fertility if they’re large or symptomatic.
A urologist can evaluate and discuss whether monitoring or treatment makes sense in your situation.

3. Hydrocele (fluid around the testicle)

A hydrocele is a fluid-filled sac that forms around a testicle, making it look swollen or
larger. The swelling is usually painless and may feel like a water balloon inside the scrotum.

Hydroceles can:

• Occur at any age, including adulthood
• Be present from birth or develop later
• Sometimes be related to inflammation, infection, or prior surgery

Many hydroceles are benign and can simply be monitored, but a healthcare professional might order an
ultrasound to confirm that the swelling is just fluid and not something more serious.

4. Epididymitis and epididymo-orchitis (infection and inflammation)

Behind each testicle is a coiled tube called the epididymis, which stores and carries sperm.
When this structure gets inflamed or infected, it’s called epididymitis. If the testicle
itself becomes inflamed too, it’s called epididymo-orchitis.

Symptoms may include:

• One-sided testicular pain and swelling (the affected side looks bigger)
• Warm, tender scrotum
• Pain with urination or ejaculation
• Fever or feeling generally unwell

These conditions are often caused by bacterial infections, including sexually transmitted infections (STIs)
like chlamydia or gonorrhea, or by urinary tract infections. They usually require antibiotics and should be
evaluated promptly by a healthcare professional.

5. Spermatocele (a fluid-filled cyst)

A spermatocele is a fluid-filled cyst that develops near the epididymis. It often feels like
a smooth, firm lump above or behind the testicle. While it can make one side appear fuller or slightly larger,
it’s usually benign and painless.

Many spermatoceles never need treatment. If they become large or uncomfortable, a urologist can discuss
surgical options.

6. Inguinal hernia

An inguinal hernia happens when part of the intestine or abdominal tissue pushes through a
weak spot in the lower abdominal wall and bulges down toward the groin or scrotum. This can make one side of
the scrotum look bigger.

Symptoms can include:

• A bulge in the groin that may get larger when you cough or strain
• Discomfort that improves when lying down
• Occasional burning or aching sensation

Severe, sudden pain with a firm, tender bulge that doesn’t go back in is an emergency (possible strangulated
hernia) and needs immediate medical attention.

7. Testicular torsion (emergency)

Testicular torsion occurs when the spermatic cord twists, cutting off blood flow to the
testicle. The affected testicle can swell rapidly and become very painful and tender. The scrotum may look
red or darker on that side, and you might feel nauseated or vomit from the pain.

This is a medical emergency. Without quick treatment (usually emergency surgery), the
testicle can be permanently damaged. If you ever have sudden, severe testicular pain, don’t wait to see if it
gets better. Go to an emergency department immediately.

8. Testicular cancer

Testicular cancer is relatively rare but is one of the most common cancers in younger men and people assigned
male at birth. It often presents as:

• A painless lump or firm area in the testicle
• Gradual swelling or enlargement of one testicle
• A feeling of heaviness in the scrotum
• A dull ache in the lower abdomen, groin, or back

Testicular cancer is highly treatable, especially when found early. That’s a big reason why learning
testicular self-exams and paying attention to changes in size or texture is so important.

When a size difference can be risky

Not every size difference is dangerous, but certain changes should always be taken seriously. Contact a
healthcare professional if you notice:

• A testicle that suddenly becomes larger over hours or days
• New or worsening pain in one testicle or the scrotum
• A firm lump, bump, or area that feels very different from the rest
• Redness, warmth, or significant tenderness
• Fever, chills, or feeling sick at the same time as testicular swelling
• Nausea, vomiting, or severe lower abdominal pain along with testicle pain

If pain is sudden and severe, especially in a younger person, go to the emergency department
right away to rule out testicular torsion. For slower changes, like a gradually enlarging testicle or a
lump that’s been there for a few weeks, schedule a prompt visit with a primary care doctor or urologist.

How to do a testicular self-exam

A monthly testicular self-exam is quick, simple, and can help you notice changes early. You’re not trying to
obsess over every tiny bump; you’re just learning what “normal for you” feels like so that “not normal”
stands out.

When to examine

The best time to examine your testicles is:

• During or right after a warm shower or bath
• When the scrotal skin is relaxed, making it easier to feel the structures inside
• Once a month, or as often as your doctor recommends

Step-by-step self-exam guide

1. Get comfortable and use both hands.
   Stand in front of a mirror. Gently move your penis out of the way so you can see and feel the scrotum
   clearly.
2. Look first.
   Check for visible swelling, changes in color, or any area that looks unusually enlarged on one side.
3. Examine one testicle at a time.
   Using the thumb and fingers of both hands, gently roll one testicle between your fingers. Move slowly from
   top to bottom and side to side.
4. Find the epididymis.
   You should feel a soft, rope-like structure at the back and top of the testicle. That’s the epididymis—it’s
   normal and often feels different from the smooth surface of the testicle itself.
5. Check for changes.
   You’re looking for:
   • Lumps or firm nodules (even pea-sized ones)
   • Areas that feel significantly harder than the rest
   • New swelling, fluid buildup, or changes in shape
6. Repeat on the other side.
   Remember that a small size difference can be normal. You’re mainly tracking new or progressive changes.

If you find something new, don’t panic—many lumps turn out to be benign. But do call a
healthcare professional and ask to be seen for an exam and possibly an ultrasound for reassurance
and accurate diagnosis.

What your doctor might do if one testicle is bigger

When you see a healthcare professional about testicular changes, they’ll typically:

• Ask about when you first noticed the size difference and whether it’s changed
• Review symptoms such as pain, fever, urinary issues, or sexual history
• Perform a physical exam of the scrotum, abdomen, and groin
• Order a scrotal ultrasound to see inside the testicles and surrounding structures
• Possibly order lab tests, like STI screening, urine tests, or blood work

Treatment depends on what’s causing the size difference:

• Infections may require antibiotics and temporary rest from sexual activity or strenuous exercise.
• Hydroceles and spermatoceles may simply be monitored or surgically treated if large or uncomfortable.
• Varicoceles can be managed conservatively or treated surgically or by minimally invasive procedures if they cause pain or fertility issues.
• Hernias are usually repaired surgically.
• Testicular torsion requires emergency surgery to untwist the spermatic cord.
• Testicular cancer is typically treated with removal of the affected testicle and, if needed, further therapies such as chemotherapy or radiation.

It can feel intimidating to talk about your testicles, but doctors see these issues all the time. Their goal
is to keep you healthy, not to judge.

Real-life style experiences and lessons learned

To make all this information more relatable, imagine a few very common scenarios that many people go through
when they notice one testicle is bigger than the other.

“I ignored it for months because I was embarrassed.”

One typical story goes like this: someone notices that one testicle seems larger and a little heavier. It’s
not super painful, just… weird. They tell themselves it’s probably nothing and keep putting off calling a
doctor because it feels awkward to talk about. Months later, the swelling is bigger, and now the anxiety is
just as large.

When they finally do see a urologist, it turns out to be a hydrocele or a varicocele—annoying, but not
life-threatening. The ultrasound is reassuring, and they often say, “I wish I’d gone sooner; I would have
saved myself a lot of stress.” The lesson here: embarrassment is temporary, but the peace of mind from a
professional check is huge.

“I noticed a lump during a shower self-exam.”

Another very common experience starts with a self-exam. Someone is in the shower, rolling each testicle
gently between their fingers, when they feel a firm, pea-sized lump that definitely wasn’t there before. Even
without pain, it feels wrong enough that they book an appointment quickly.

In some cases, the lump turns out to be a benign cyst or a spermatocele. In other cases, it is an early
testicular cancer. But because it was caught early, treatment is far more effective, and long-term outcomes
are usually excellent. The self-exam becomes a powerful, life-changing habit rather than just a suggestion
they once read online.

“Sudden pain made me drop everything and go to the ER.”

There’s also the more dramatic story: someone experiences sudden, severe testicular pain on one side, along
with swelling and nausea. There’s no time to overthink or google; they head straight to the emergency
department. After a fast evaluation and ultrasound, the doctors diagnose testicular torsion.

In this situation, the speed of seeking help makes all the difference. Prompt surgery can save the testicle
and prevent long-term damage. Many people who go through this say that they’re grateful they didn’t wait even
an extra hour, and they often encourage friends and partners to take testicular symptoms seriously.

“Talking about it lowered my anxiety.”

Another underrated experience is simply opening up to a trusted person. Some people talk to a partner, close
friend, or healthcare professional and realize their fear is much larger than the actual risk. A brief
appointment, a quick exam, or an ultrasound often confirms that nothing dangerous is going on.

After that, many people feel more comfortable doing regular self-exams because they understand what
“normal” feels like, and they’ve had a professional confirm it. It’s like having a baseline map of your body:
much less scary once you know the landmarks.

What you can take from these experiences

Across all of these scenarios, a few themes show up again and again:

• Embarrassment is common but shouldn’t be a barrier. Healthcare professionals deal with this area of the body every day.
• Early action is powerful. Whether the cause is infection, torsion, or cancer, early evaluation almost always leads to better outcomes.
• Knowledge reduces fear. Once you know that mild size differences can be normal, you can focus on the real warning signs instead of worrying about every minor asymmetry.
• Self-exams are a skill, not a test you have to ace. The more you practice, the more confident you become in recognizing what’s normal for your body.

So if you’ve noticed that one testicle is bigger than the other, consider this your friendly nudge: learn how
to examine yourself, pay attention to changes, and loop in a healthcare professional when something doesn’t
feel right. You’re not overreacting; you’re taking care of your health.

Bottom line

It’s very common for one testicle to be slightly bigger or hang lower than the other. On its own, that
difference often isn’t a sign of disease. But if the size difference is new, rapidly changing, painful, or
associated with lumps, heaviness, or systemic symptoms like fever, it’s important to seek medical care.

Regular testicular self-exams, knowing your normal anatomy, and being willing to talk to a doctor if
something feels off are simple steps that can protect your health. Your future self will thank you for paying
attention now.