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 and totems, fully reflecting people's reverence for the reproductive organs. The size of the penis varies among races and individuals. In China, the average length (non-erect) of the penis for 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 use a ruler to measure the length from the pubic symphysis to the tip of the penis.
Measurement of erect penis length: Assume an upright posture, grip the glans of the penis and pull it forward forcefully until it cannot be elongated further. Use a ruler to measure the length from the pubic symphysis to the glans (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 the penis buried in the fat, making it appear smaller. In such cases, you can push the abdominal fat with your hand during measurement. 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 the 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 develop a sense 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 normal 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 normal 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 of the penis was 13.34 cm, similar to the calculated erect length of 13.08 cm, suggesting that traction can represent the erect length.
It is evident that different authors' measurements vary, and the results are also influenced by region and ethnicity. Additionally, the length of the penis in a normal state is not constant in the same person; it may shorten under stress, cold, or severe fatigue. Moreover, measurement methods differ significantly, making it difficult to judge whether the penis is normal solely based on length. Therefore, the above numbers are only for reference and should not be rigidly compared with one's own length. Clinicians also avoid judging normality based on penis length. As long as normal sexual intercourse can be achieved 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 of the penis. For convenience, 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, testosterone produced under the action of hCG secreted by the placenta plays a role.
(2) Mid-to-late pregnancy (6 months): The penis grows rapidly, reaching 2.5-3.5 cm at birth. At this stage, the fetal pituitary begins to secrete gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), and follicle-stimulating hormone (FSH).
(3) From birth to prepuberty (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: The pituitary and testicular hormones are secreted in abundance, and the penis grows rapidly, reaching adult size in about 5 years, increasing in both length and thickness.
In old age, when sex hormone levels significantly decrease or after surgical castration, the penis may undergo secondary atrophy. If secondary impotence has been untreated for many years, it may also lead to pathological atrophy, which is not the usual issue of "use it or lose it" but rather the result of degenerative changes in smooth muscle fibers.
In summary, the differentiation and development of the penis rely entirely on the body's testosterone levels. If testosterone secretion is insufficient during weeks 6-9 of pregnancy, the penis will develop at a slower rate, resulting in a smaller penis at birth.
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, no erectile function, poor secondary sexual characteristics, sexual dysfunction, infertility, and no sperm is considered abnormally developed.
Causes of true micropenis include:
(1) High gonadotropin hypogonadism originating in the testes, where the hypothalamus and pituitary are normal but the testes are diseased, unable to execute commands to produce sex hormones and sperm.
(2) Low gonadotropin hypogonadism, where the hypothalamus and pituitary are diseased and cannot issue commands to secrete testosterone.
The above conditions have been described 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. Such normal physiological differences should not cause undue concern. As for female sexual satisfaction and mutual sexual harmony, they are primarily due to 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 room temperature should be around 25°C, and the person should be calm and properly rested. Lift the penis flat with your hand, gently press the pubic symphysis with one end of a hard ruler, compressing the subcutaneous fat layer as much as possible, and measure the other end from the glans to the external urethral orifice to determine the normal length. Then, use a tape measure to measure the circumference of the penis shaft 1 cm away from the corona. Since patients may become tense or uncomfortable in the clinic, they often cannot achieve erection in front of the doctor. Therefore, the traction length of the penis is often used as a substitute for the erect length.