Patient's question:
I'm curious, I'm 16 years old. How long is the longest length of a man's penis and how short is the shortest length. I haven't experienced it.Doctor's answer:
The penis is an important part of the male reproductive system and is very significant to a man. As early as ancient times, the penis appeared in stone carvings of totems, fully reflecting people's reverence for reproductive organs. The size of the penis varies among races and individuals. In China, the average penis length (non-erect) of men (18-45 years old) ranges from 4.5 to 8.8 cm, with an average of 6.5 cm and an average transverse diameter of 2.5 cm. The average circumference at the middle of the penis is 8 cm. So, how is the length of the penis measured? Here is a method commonly used by doctors.Measurement of non-erect penis length: At room temperature of 18°C, assume an upright posture, lift the penis to form a 90° angle with the body, and measure the length from the pubic symphysis to the top of the penis head with a ruler.
Measurement of erect penis length: Assume an upright posture, grip the penis head with your hand and pull it forward until it cannot be elongated further. Measure the length from the pubic symphysis to the penis head with a ruler (the length after traction is essentially the same as the erect length). A length of 8 cm or more is considered normal.
It is worth noting that some men, due to obesity and excess abdominal fat, may have part of their penis buried in the fat, making it appear smaller. During measurement, you can push the abdominal fat with your hand. However, men with smaller penises do not need to worry, as proper sexual techniques will not affect sexual life.
Formula for estimating whether the penis size is normal! (Asia) The International Men's Health Organization (MTD) conducted nearly 30 years of research and concluded:
Normal penis length M = (height T - 105) 0.618 / 3.14 (cm)
Normal penis diameter D = M / 3.14 (cm) (Europeans = Asians / 1.414 / 0.618) (cm)
How long is the standard length of a penis? Most young men are curious and often secretly compare the size of their penises with others in places like swimming pools. If they find their penis is shorter than others, they may feel a shadow of inferiority, shame, and frustration, even avoiding public baths or swimming pools altogether. Is the problem really that serious? To answer such questions, one must first clarify what constitutes an abnormal penis. Next, it must be determined whether it is abnormal development or just individual variation within the normal range. Finally, and most importantly, if the penis is slightly smaller, will it affect normal sexual life? In other words, can it provide pleasure to the wife?
Like height, weight, and facial features, the penis varies greatly in length and thickness. Shi Chengli measured the penis size of 1,412 healthy Chinese young men and the erect length of 126 healthy men. The results showed that the longest penis was 14.5 cm, the shortest 4 cm, with an average of 8.375 cm; the maximum circumference was 12 cm, the minimum 4.5 cm, with an average of 8.3 cm. During erection, the longest was 16 cm, the shortest 9 cm, with an average of 12 cm; the maximum circumference during erection was 14 cm, the minimum 8 cm, with an average of 10.75 cm. Liu Guozhen et al. surveyed 1,000 normal adult men and found that the penis length ranged from 4.9 to 8.6 cm, with an average of 6.55 cm, the longest being 10.6 cm, and the shortest 3.7 cm. Wu Weicheng et al. measured 2,547 16-40-year-old male college students and found an average length of 7.43 cm and an average circumference of 8.17 cm; the average traction length was 13.34 cm, similar to the calculated erect length of 13.08 cm, suggesting that traction can represent the erect length.
It is clear that different authors' measurements vary, and the results are also influenced by region and ethnicity. Additionally, a person's penis length is not constant under normal conditions; it can shorten due to stress, cold, or severe fatigue. Moreover, the methods of measurement themselves differ significantly, making it difficult to judge whether a penis is normal based solely on length. Therefore, the above numbers are only for reference and should not be rigidly compared to one's own length. Clinicians are also reluctant to judge normality based on penis length. As long as sexual intercourse is normal and the ability to reproduce is maintained, it is considered normal. Otherwise, this family line would have been eliminated long ago.
To further explain the factors or causes of a larger or smaller penis, let us revisit the development and growth process of the penis. For convenience of description, we divide it into four stages:
(1) Weeks 10-12 of pregnancy: The penis has just begun to differentiate and is only 3.5 mm long. At this stage, the testosterone produced under the action of hCG secreted by the placenta is active.
(2) Middle and later stages of pregnancy (6 months): The penis grows rapidly, reaching 2.5-3.5 cm at birth. At this time, the fetal pituitary begins to secrete gonadotropin-releasing hormone (GnRH) and follicle-stimulating hormone (FSH).
(3) From birth to pre-puberty (around 7 years old): Penis growth is slow, due to the slower development of the hypothalamus and pituitary and lower testosterone levels.
(4) After puberty begins: The pituitary and testicular hormones are secreted vigorously, and the penis grows rapidly, reaching adult size in about 5 years, becoming longer and thicker. When the level of sex hormones significantly decreases in old age or after surgical castration, the penis may undergo secondary atrophy. If secondary impotence has been without sexual contact for many years, it may also lead to pathological atrophy. This is not the issue of "use it or lose it" in general, but rather the result of degenerative changes in smooth muscle fibers.
In summary, the differentiation and development of the penis rely entirely on the testosterone level in the body. If testosterone secretion is insufficient during weeks 6-9 of pregnancy, the penis develops at a slower rate, and the penis will be smaller at birth.
So, what constitutes a truly small penis? A penis shorter than 2.5 cm before puberty and shorter than 5 cm after puberty, with abnormal development and no erectile function; especially poor development of secondary sexual characteristics, sexual dysfunction, infertility, and no sperm, can be considered abnormal penis development.
The causes of true micropenis include:
(1) High gonadotropin hypogonadism originating in the testes, where the hypothalamus and pituitary are normal and can issue strong commands, but the testes are diseased and cannot execute the command to produce sex hormones and sperm.
(2) Low gonadotropin hypogonadism, where the hypothalamus and pituitary are diseased and cannot issue commands to secrete testosterone. These two conditions have been described separately in this book.
(3) Partial androgen insensitivity syndrome, where the penis is insensitive to androgens. The patient's testosterone levels are normal, but secondary sexual characteristics are abnormal, and even hypospadias may occur.
(4) Idiopathic micropenis, where the cause or etiology remains unknown.
Let us return to the woman mentioned earlier. Since she became pregnant about 9 months after marriage and gave birth to a healthy son, it indicates that her husband's sexual function is normal and there are no endocrine issues. His penis clearly falls within the normal range. For such normal physiological differences, there is no need to worry. As for female sexual satisfaction and mutual sexual harmony, they are primarily caused by a lack of sexual knowledge and techniques, not the size of the penis.
By the way, the method of measuring penis length is important: first, measure in a flaccid state, and second, measure the change during erection. The measurement should be done at a room temperature of around 25°C after calming down and resting appropriately. Lift the penis flat with your hand, press one end of the ruler slightly against the pubic symphysis, and compress the subcutaneous fat layer as much as possible. The other end should be used as a reference point at the external urethral orifice of the glans penis, and the number read is the normal length of the penis. Then, use a tape measure to measure the circumference of the penile shaft 1 cm away from the coronal margin. Since patients may become tense or uncomfortable in the clinic, they often cannot achieve erection in front of the doctor, so the traction length of the penis is often used as a substitute for the erect length.