Testicle size is largely determined by genetics, but several factors can cause them to shrink below your baseline, and addressing those factors can restore lost volume. In fertile adult men, each testicle typically measures between 17 and 50 cubic centimeters (roughly the size of a small plum to a large walnut), with the average falling around 31 to 33 cc. If yours fall within that range, they’re normal. If they’ve noticeably shrunk or you’re starting from a genuinely small baseline, the path forward depends on what’s causing it.
Why Testicles Shrink in the First Place
The most common reason men notice smaller testicles is hormonal disruption. Anabolic steroids and testosterone replacement therapy are the biggest culprits. When you flood your body with external testosterone, your brain stops sending the signals that tell your testicles to produce their own. Without that stimulation, the tissue that makes sperm (which accounts for most of testicular volume) gradually wastes away. The longer you’re on exogenous hormones, the more pronounced the shrinkage.
Other causes include varicoceles (enlarged veins in the scrotum that raise local temperature and impair blood flow), heavy alcohol use, certain infections like mumps orchitis, and chronic exposure to excessive heat. Age plays a role too. Testosterone production naturally declines after about age 30, and testicular volume can slowly decrease alongside it.
Recovery After Steroid Use
If steroid-induced shrinkage is what brought you here, the encouraging news is that most testicular function recovers after you stop. A study published in The Journal of Clinical Endocrinology & Metabolism tracked men who had used nonprescribed androgens for an average of over two years. Hormone levels began bouncing back within about 7 to 11 months. Sperm concentration recovered around 10 months, and total sperm output took roughly 14 months.
The less encouraging part: testicular volume was the one variable that didn’t fully return to pre-use levels, even after extended recovery periods. The testicles regained function, but some residual reduction in physical size persisted compared to men who had never used androgens. That said, partial recovery still happened, and the longer you’ve been off, the more ground you regain. Recovery timelines vary depending on how long and how heavily you used.
Hormonal Treatments That Increase Size
For men with a specific hormonal condition called hypogonadotropic hypogonadism, where the brain doesn’t produce enough of the hormones that stimulate the testicles, medical treatment can dramatically increase testicular volume. In a prospective study, men treated with a combination of medications that mimic or boost those brain signals saw their testicular volume roughly double after 12 months of treatment. Men who started with slightly larger testicles tended to respond better, suggesting that more remaining functional tissue gives the treatment more to work with.
This isn’t something you self-prescribe. It requires blood work to confirm the specific hormonal deficiency and ongoing monitoring. But if you’ve been told your testosterone is low and your testicles are notably small, it’s worth asking your doctor whether the issue originates in the brain’s signaling rather than the testicles themselves, because the treatment approach and the potential for size increase are very different depending on the answer.
Nutrients That Support Testicular Function
Zinc is the mineral most directly tied to testicular health. Low zinc levels in seminal fluid are associated with reduced sperm count, poor motility, and lower testosterone production. Zinc is concentrated in the testicles at higher levels than almost anywhere else in the body, and deficiency impairs the cellular machinery that produces sperm. Good dietary sources include oysters, red meat, pumpkin seeds, and lentils. Most men in developed countries get enough zinc from food, but vegetarians, heavy drinkers, and endurance athletes are more likely to run low.
Vitamin D also plays a supporting role. Receptors for it are found throughout testicular tissue, and low vitamin D status has been linked to lower testosterone in observational studies. If you live in a northern climate or spend most of your time indoors, a simple blood test can tell you whether supplementation makes sense. Neither zinc nor vitamin D will make healthy, normal-sized testicles grow larger, but correcting a deficiency can help restore function and size that was lost due to that deficiency.
Temperature and Lifestyle Factors
Testicles hang outside the body for a reason: they need to stay about 2 to 3 degrees cooler than core body temperature to function properly. Chronic overheating doesn’t necessarily shrink them visually, but it impairs the sperm-producing tissue inside, which is functionally similar to mild atrophy.
Research on scrotal cooling bears this out. In one study, men with poor semen quality who used overnight cooling (lowering scrotal temperature by about 1°C) for 12 weeks saw highly significant improvements in sperm concentration and total sperm output. The practical takeaways are straightforward: avoid prolonged hot tub or sauna sessions if testicular health is a priority, don’t keep a laptop directly on your lap for hours, wear loose-fitting underwear, and take breaks from sitting for long stretches. These changes won’t make your testicles visibly bigger, but they protect the tissue that determines how well your testicles actually work.
What Won’t Work
Supplements marketed as “testicle enlargement” pills have no clinical evidence behind them. Herbal blends containing tribulus, fenugreek, or maca may modestly support libido or energy in some men, but none have been shown to increase testicular volume in controlled studies. The same goes for exercises or massage techniques sometimes promoted online. Testicles are glandular organs, not muscles. You can’t train them to grow.
If your testicles are within the normal range and you’re simply comparing yourself to what you see in pornography, keep in mind that camera angles, body fat percentage, and selection bias heavily distort that reference point. A man with very low body fat and a closely trimmed groin will appear to have noticeably larger testicles than the same man at a higher body fat with more pubic hair, even though nothing has actually changed. Losing excess body fat and grooming the surrounding area are the most immediate ways to change the visual appearance without changing the testicles themselves.
When Small Testicles Signal a Real Problem
Testicles that measure below about 12 cc (smaller than a large grape) in an adult are considered clinically small and warrant investigation. This can indicate Klinefelter syndrome (a chromosomal condition present from birth), pituitary disorders, or severe hormonal deficiency. If small testicles are accompanied by low energy, reduced sex drive, difficulty building muscle, or breast tissue development, these are signs of an underlying hormonal issue that responds well to treatment when caught.
A sudden change in size, particularly on one side, is also worth attention. Rapid swelling could indicate infection or torsion (a medical emergency). Gradual shrinkage on one side might point to a varicocele, which is treatable and present in roughly 15% of men. An ultrasound can measure exact volume and identify structural issues that a physical exam might miss.