Scrotal sagging is a natural process driven by gravity, heat, aging, and muscle relaxation. The scrotum is designed to hang lower under certain conditions, and several biological factors determine how much it does so. Whether you’re curious about why sagging happens or looking to understand the mechanics behind it, here’s what actually controls scrotal hang and what affects it over time.
Why the Scrotum Hangs in the First Place
The scrotum exists to keep the testicles cooler than core body temperature, which is essential for sperm production. Its thin skin has no subcutaneous fat, sparse hair, and a high concentration of sweat glands, all of which help dissipate heat. When surrounding temperatures rise, the scrotal muscles relax and let the testicles drop further from the body, increasing the surface area available for cooling. When it’s cold, the opposite happens: muscles contract, pulling the testicles closer to the abdomen to conserve warmth.
Two muscles control this movement. The dartos is a smooth muscle embedded in the scrotal skin itself. It responds to cold by producing a slow, writhing contraction that tightens the skin and elevates the testicles. The cremaster is a striated muscle originating from the abdominal wall that runs along the spermatic cord. It produces a quicker lifting action, often triggered by touch on the inner thigh. When both muscles are relaxed, the scrotum hangs at its lowest.
Heat Is the Fastest Way to Increase Hang
Because scrotal position is fundamentally a thermoregulation response, warmth is the most immediate factor that causes lower hang. Hot baths, saunas, warm weather, and even sitting for long periods with your legs together all raise scrotal temperature. The dartos and cremaster muscles relax in response, and the scrotum drops noticeably. This is completely reversible and happens dozens of times throughout a normal day as your body adjusts to temperature changes.
How Aging Causes Permanent Sagging
Over time, scrotal sagging becomes more pronounced and less reversible. Two processes drive this. First, gravity continuously pulls on the scrotal skin, gradually stretching it. Second, the skin loses elasticity as collagen and elastin break down with age, the same process that causes skin to loosen elsewhere on the body. These are classified as intrinsic aging factors, meaning they happen regardless of lifestyle.
Extrinsic factors can accelerate the process. Sun exposure, friction, and general wear on the skin all contribute to faster elasticity loss. The combination of gravity-dependent stretching and declining skin elasticity means that scrotal laxity tends to increase steadily from middle age onward. By the time most men reach their 60s and 70s, the difference from their 20s is substantial.
Hormones and Scrotal Skin
Testosterone plays a role in scrotal tissue development. The scrotal skin contains androgen receptors, and research on underdeveloped scrotums has shown that topical testosterone can increase scrotal surface area by 30 to 50 percent in responsive cases, along with increasing the number of rugae (the characteristic wrinkled folds). This suggests that androgen levels influence scrotal skin volume and texture. As testosterone naturally declines with age, this may contribute to changes in scrotal tissue quality over time, though the relationship between normal testosterone fluctuations and everyday scrotal hang hasn’t been precisely measured.
Weight Loss and Body Composition
Significant weight changes can affect scrotal appearance. In men who carry substantial excess weight, fat deposits around the groin can obscure the penis and alter how the scrotum sits. After major weight loss, the skin in this area often remains loose because of stretched-out dartos attachments and loss of structural support. Even with weight loss, that ptotic (drooping) skin tends to persist without surgical correction. So large fluctuations in body weight, particularly gaining and then losing a significant amount, can leave the scrotal skin permanently laxer than it was before.
Why Scrotal Stretching With Weights Is Risky
Some people use weights or manual stretching to intentionally increase scrotal hang. This carries real risks. In an experimental study on the effects of stretching the spermatic cord (the structure connecting the testicles to the body), even brief, moderate stretching force caused significant thinning of the vas deferens wall, the tube that carries sperm. Testicular weight also decreased in the stretched groups compared to controls. Most concerning, tissue death occurred in the testicles of roughly half the animals in both stretching groups.
The spermatic cord contains blood vessels, nerves, and the vas deferens. Applying traction to the scrotum inevitably transmits force to these structures. While the animal study used controlled surgical conditions rather than external weights, the findings highlight that the tissues inside the scrotum are vulnerable to stretch injury. Damage to the vas deferens can impair fertility, and compromised blood flow can cause testicular atrophy or tissue death.
Medical Conditions That Affect Scrotal Hang
A varicocele, which is an enlargement of veins within the scrotum, can make one side hang noticeably lower than the other. Varicoceles are common, affecting roughly 15 percent of adult men, and they tend to develop on the left side. Over time, a varicocele can cause the affected testicle to shrink due to tissue loss, which may change the overall balance and appearance of the scrotum. If one testicle seems significantly lower or smaller than the other, a varicocele is one possible explanation worth having evaluated.
Surgical Options Exist in Both Directions
Most surgical procedures involving scrotal laxity are designed to reduce sagging, not increase it. Scrotal reduction surgery removes excess skin through various incision patterns, including crescent-shaped horizontal cuts, inverted-U incisions, or vertical resections. In one common approach, a check mark-shaped incision removes redundant tissue along both sides, and the closure creates an inverted Y along the midline. In studies of this procedure, 84 percent of patients reported an improved perception of penile length afterward, since excess scrotal skin can visually obscure part of the shaft.
Less invasive alternatives using absorbable suspension sutures have also been explored, though surgical excision remains the standard. These procedures are typically performed for comfort or cosmetic reasons in men who find excess scrotal skin bothersome during physical activity or daily life.
For men seeking the opposite effect, there are no widely established surgical procedures designed to increase scrotal hang. The medical literature focuses almost exclusively on reduction, reflecting the fact that progressive sagging is the natural trajectory and the more common concern.