Patient's question:
I am 19 years old this year. In terms of age, I'm not considered old yet, and I'm still growing and developing. However, I often feel that my penis is too small. Are there any methods to make it bigger?Doctor's answer:
Most young men are curious, and in places like public baths, they often secretly compare the size of their penises with those around them. Once they discover that their penis is smaller than others', they may develop a sense of inferiority and feel ashamed, frustrated, and disheartened, to the extent that they no longer want to go to public baths or swimming pools. (How far is asexuality from you?) Is the problem really that serious?To answer such questions, we first need to clarify what constitutes an abnormal penis. Next, we must determine whether it is a developmental abnormality or simply an 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?
The penis, like height, weight, and facial features, varies greatly in length and circumference. Shi Chengli of China once measured the penis sizes of 1,412 healthy young Chinese men and the erect lengths of 126 healthy men. The results showed that in a normal state, the longest penis was 14.5 cm, the shortest 4 cm, with an average of 8.375 cm in length; the circumference ranged from a maximum of 12 cm to a minimum of 4.5 cm, with an average of 8.3 cm. During erection, the longest penis was 16 cm, the shortest 9 cm, with an average of 12 cm; the circumference during erection ranged from a maximum of 14 cm to a minimum of 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 in a non-erect state 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 the penises of 2,547 male college students aged 16–40 and found an average length of 7.43 cm and an average circumference of 8.17 cm. The average penile stretch was 13.34 cm, which was similar to the calculated erect length of 13.08 cm, suggesting that penile stretch can represent the length after erection. It is clear that different authors' measurements vary, and the results are also influenced by region, ethnicity, and other factors. Additionally, a person's penis length can fluctuate in a normal state, such as when they are tense, cold, or severely fatigued. Moreover, the methods of measurement themselves differ significantly, making it difficult to judge whether a penis is normal based solely on length. Therefore, these figures are only for reference and should not be rigidly compared with 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, the penis 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's revisit the process of penile development. For convenience, we can divide it into four stages:
(1) Weeks 10–12 of pregnancy: The penis has just begun to differentiate, measuring only 3.5 mm in length. At this stage, testosterone produced by placental hCG plays a role.
(2) Middle and late 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 luteinizing hormone (LH) and follicle-stimulating hormone (FSH).
(3) From birth to before puberty (around age 7): Penis growth is slow due to the slower development of the hypothalamus and pituitary, as well as low testosterone levels.
(4) After puberty: The pituitary and testes secrete hormones vigorously, causing the penis to grow rapidly, reaching adult size in about 5 years. It also increases in thickness. When elderly hormone levels drop significantly or after surgical castration, the penis may undergo secondary atrophy. If secondary erectile dysfunction persists for many years without sexual activity, it may lead to pathological atrophy. This 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 more slowly, resulting in a smaller penis 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 secondary sexual characteristics, sexual dysfunction, infertility, and no sperm, can be considered abnormally developed. The causes of true micropenis include:
(1) Primary testicular hypergonadotropic hypogonadism: In this case, the hypothalamus and pituitary are normal and can issue strong commands, but the testes are diseased and cannot execute the commands to produce hormones and sperm.
(2) Hypogonadotropic hypogonadism: This occurs when the hypothalamus and pituitary are damaged and cannot issue instructions to secrete testosterone. These two conditions have been described in this book.
(3) Partial androgen insensitivity syndrome: In this case, the penis is insensitive to androgens. The patient's testosterone levels are normal, but their secondary sexual characteristics are abnormal, and they may even have hypospadias.
(4) Idiopathic micropenis: The cause remains unknown.
Let's 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, ruling out any endocrine issues. His penis clearly falls within the normal range. There is no need to worry about such normal physiological differences. As for female sexual satisfaction and mutual sexual harmony, they are primarily caused by a lack of sexual knowledge and skills, not the size of the penis. By the way, the method of measuring penis length is important: first, measure in a flaccid state, and then measure the change during erection. The room temperature should be around 25°C, and the person should be calm and rested. The penis should be held flat, and one end of a ruler should be pressed firmly against the pubic symphysis, compressing the subcutaneous fat layer as much as possible. The other end should be aligned with the urethral meatus of the glans to read the normal flaccid length. A tape measure can then be used to measure the circumference of the penis 1 cm below the corona. Since patients may become tense or uncomfortable in the clinic, they often cannot achieve erection in front of the doctor, so the stretched length of the penis is often used as a substitute for the erect length.