What Are the Signs That Your Penis Is Growing?

Penile growth during puberty follows a predictable pattern of physical changes that unfold over several years, and the earliest signs are usually not about the penis itself. The first reliable indicator is testicular enlargement, which typically begins between ages 9 and 14 and precedes noticeable penile growth by roughly a year. From there, a cascade of changes in pubic hair, body odor, skin texture, and overall body proportions signals that hormones are actively driving development, including growth of the penis in both length and girth.

Testicular Growth Comes First

The very first sign that penile growth is on its way is an increase in testicle size. Before any change in penile length is visible, the testes begin producing more testosterone and gradually enlarge. This stage, often called Tanner stage 2 in clinical terms, is the starting gun for male puberty. A boy or his parents might notice that the scrotum looks slightly larger or hangs a bit lower. The skin of the scrotum also tends to thin out and take on a slightly reddish or darker tone.

This testicular change is easy to miss because it happens gradually. But it is the most dependable early marker. If the testes have not begun to enlarge by age 14, that is generally the point at which a doctor might want to check hormone levels to rule out delayed puberty or an underlying condition.

The Typical Sequence of Changes

After the testes start growing, the penis itself begins to lengthen. This usually happens around ages 11 to 13, though the range of normal is wide. Initially, the penis grows mostly in length before it begins to increase in girth. Pubic hair appears around the same time or shortly after, starting as fine and sparse at the base of the penis and gradually becoming coarser and more widespread.

Research modeling puberty from height and secondary sexual characteristics in boys found that the age of peak growth velocity, including genital development, falls around 13 to 14 years old, with a standard deviation of roughly one year in either direction. Tanner stages advanced at a peak rate of about 1.2 to 1.8 stages per year during this period.¹ That means the most rapid genital growth tends to overlap with the adolescent growth spurt in height, though the two do not always peak at the exact same moment.

Other signs that accompany penile growth during this phase include:

Voice changes: The larynx enlarges under testosterone’s influence, causing the voice to crack and eventually deepen.
Body hair: Underarm hair, leg hair, and eventually facial hair begin to appear, typically after pubic hair is already established.
Skin changes: Increased oil production leads to acne for many boys, a direct effect of rising androgen levels.
Spontaneous erections: Erections become more frequent and sometimes happen without any obvious trigger, a sign that blood flow to the penile tissue is increasing as the organ develops.

These changes do not all happen at once. Puberty in boys typically spans about four to five years from start to finish, and genital growth continues through much of that window. Some boys will notice most of their growth early, while others are still developing well into their late teens.

What Growth Actually Feels Like

Unlike a growth spurt in height, which can sometimes cause growing pains in the legs, penile growth is generally painless. What boys often notice instead is a change in how the penis looks and behaves. It may appear visibly longer when flaccid, or feel heavier. Erections become firmer and larger over time as the erectile tissue, specifically the spongy bodies inside the shaft, expands under hormonal stimulation.

Androgens play a central role in this process by regulating the growth of smooth muscle within the erectile tissue and influencing the connective tissue that gives the penis its structural integrity.² Animal research shows that when androgens are absent, penile tissue atrophies, smooth muscle content drops, and fatty tissue accumulates in areas that should be filled with functional erectile tissue. This is part of why hormonal conditions that reduce androgen levels during puberty can limit penile development, and why hormone treatment in such cases can restore growth.

Another change boys may notice is that the glans, or head of the penis, becomes more prominent. In uncircumcised boys, the foreskin typically becomes easier to retract as the penis grows and the tissue loosens. The overall shape of the penis becomes more defined as girth increases, usually in the later stages of puberty after the initial length growth has occurred.

How Long Growth Continues

Most penile growth is complete by age 16 to 18, though some boys continue to see small changes into their early twenties. The pace slows considerably after the peak growth period around ages 13 to 15. By the time other signs of puberty are wrapping up, such as reaching adult height and having a fully developed pattern of body hair, penile growth has usually plateaued as well.

A common concern is whether the penis will keep growing after puberty ends. For the vast majority of men, the answer is no. Once the growth plates in the long bones close and testosterone levels stabilize at adult levels, the penis does not continue to lengthen. Research on adult men receiving long-term testosterone therapy found no significant changes in penile length.³ So while testosterone is essential for growth during puberty, adding more of it after the developmental window has closed does not restart the process.

When Growth Seems Delayed

Some boys enter puberty later than their peers, and the worry that something is wrong can be intense. Constitutional delay of puberty, the medical term for being a “late bloomer,” is the most common reason a boy might not show signs of genital growth by age 13 or 14. In most of these cases, puberty eventually starts on its own and proceeds normally, just on a later schedule.

A separate concern is micropenis, which is clinically defined as a stretched penile length more than 2.5 standard deviations below the mean for age.⁴ This is a specific medical diagnosis, not a general descriptor for a penis that seems small. In young children and prepubertal boys, micropenis is sometimes treated with short courses of hormones. For boys under 11, low-dose testosterone injections given monthly for a few months can stimulate penile growth. For boys over 11, human chorionic gonadotropin injections are sometimes used to prompt the body’s own testosterone production.⁵

In rare conditions where the body cannot properly convert testosterone to its more potent form, dihydrotestosterone, penile growth can be significantly impaired. One study of boys with this specific enzyme deficiency found that applying DHT directly to the skin increased median stretched penile length from 2.6 cm to 4.4 cm in prepubertal patients, bringing them much closer to the normal range.⁶ These are specialized clinical scenarios, but they illustrate that when hormonal signals are restored, the tissue is capable of responding with real growth.

Why Body Composition Changes the Picture

One of the most misunderstood aspects of penile size, especially during and after puberty, is how much body fat affects perceived length. The penis is anchored to the pubic bone, and the visible portion extends from there. When a boy or man carries excess weight in the lower abdomen and pubic area, a fat pad forms that can conceal a significant portion of the shaft. This makes the penis look shorter than it actually is, even though the underlying anatomy has not changed.

In more extreme cases, this leads to what doctors call buried penis, a condition where the penis is substantially hidden by surrounding skin and fat. In adult men, this occurs most often as a result of obesity.⁷ During puberty, weight gain is common and can temporarily give the impression that the penis is not growing or has even gotten smaller, when in reality it is being obscured by surrounding tissue. Weight loss in these situations often “reveals” length that was always there.

This is worth knowing because a boy who gains weight during early puberty might feel alarmed that his penis seems small relative to the rest of his body. The issue is usually one of proportion and visibility rather than actual underdevelopment. Doctors assessing penile size in clinical settings measure from the pubic bone, pressing back the fat pad, precisely to avoid this source of error.

How Doctors Actually Measure

If you are trying to track growth, it helps to know how it is done in clinical settings, because casual self-measurement is unreliable. There is no universally standardized technique, but the most widely used method involves measuring along the top of the penis from the point where the shaft meets the pubic skin down to the tip of the glans.⁸ This can be done on the flaccid penis, the stretched flaccid penis, or the erect penis. The stretched flaccid measurement correlates well with erect length for most people and is the standard used in pediatric assessments because it does not require an erection.

Some researchers measure from the pubic bone itself, pressing a ruler firmly against the fat pad to reach the bone.⁹ This bone-pressed method gives a more consistent reading regardless of body fat and is useful for comparing measurements over time. Measuring from the underside, from the side, or without pressing to the bone introduces enough variability that apparent changes in length may just be measurement error. If you are going to check for growth, use the same method each time and do not obsess over small differences.

Size Anxiety and When Perception Goes Wrong

Worry about penis size is extremely common among adolescent boys and adult men, and the gap between actual measurements and how a person perceives their own body can be surprisingly large. Looking down at your own body from above foreshortens the view and makes the penis appear shorter than it would from a neutral angle. Comparing yourself to others in locker rooms or, more commonly now, to images online introduces further distortion, since what people encounter in pornography or social media is not representative of average anatomy.

For some men, concern about penis size crosses into a clinical condition related to body dysmorphic disorder. Research comparing men with body dysmorphic disorder focused on penis size to men who were simply anxious about their size found that both groups had attempted to alter their penis size at significantly higher rates than controls, most commonly through exercises like jelqing. Reported success rates of all these attempts were low.¹⁰ The study found that no men in the control group had attempted any size-altering procedures at all, which suggests that the impulse to “fix” something is itself a marker of anxiety rather than a response to an objective problem.

This matters for adolescents because puberty is a period of heightened self-consciousness. A boy whose growth has not yet started, or who develops later than his friends, may become fixated on the idea that something is wrong. In almost all cases, the answer is simply that development has not finished yet. Pediatricians and adolescent medicine specialists hear these concerns constantly, and a quick physical exam can usually confirm that development is proceeding within the normal range.

Penile Traction Devices and What They Actually Do

Adult men who feel their penis is shorter than they would like sometimes turn to mechanical traction devices, which apply gentle, sustained stretching force over weeks or months. These are distinct from the unregulated “enhancement” products sold online with exaggerated claims. Clinical research on traction devices has shown modest but real results in specific medical populations. One preliminary study found that a penile extender increased length in men with shortened penises.¹¹ A randomized controlled trial in men recovering from prostate surgery found that traction therapy preserved about 1.3 cm more penile length at six months compared to a control group that did not use the device.¹²

Traction devices have also been studied in men with Peyronie’s disease, a condition involving scar tissue that curves and sometimes shortens the penis. A review of that literature found evidence supporting improved penile length and reduced curvature in selected cases.¹³ The key context here is that these devices have been studied in men with medical conditions that caused shortening, not in healthy men trying to exceed their natural size. Whether they produce meaningful gains in men without a medical indication is far less clear, and the commitment involved, often hours per day for months, limits their practicality.

For adolescents wondering whether their penis is still growing, traction devices are not relevant. Normal pubertal development is driven by hormones, not mechanical force, and the tissue remodeling that happens during puberty is far more extensive than anything a device can achieve.

How Others Perceive Size

Part of what fuels anxiety about penile growth is the assumption that size matters enormously to potential partners or to social standing. Research using computer-generated male figures that varied in penis size, height, and body shape found that while a larger penis did contribute to ratings of attractiveness and perceived fighting ability, the effect was weaker than the effects of height and shoulder-to-hip ratio.¹⁴ In both in-person and online versions of the study, penis size was consistently the weakest of the three traits studied in terms of its influence on attractiveness ratings. Selection was strongest on height in one setting and on body shape in the other.

This does not mean size is irrelevant to anyone, but it does suggest that the cultural weight placed on it is disproportionate to how much it actually influences people’s assessments. For a teenager in the thick of puberty, that perspective can be hard to internalize, but the evidence consistently points to penis size being a much smaller part of the picture than it feels like from the inside.