Penis in its natural state 4cm is normal, but also affected by the external environment and mental factors. If the length of the penis in the natural state of 4cm, which is within the normal range, but in the external temperature and personal mental condition changes penis length will also change. Generally speaking, 4-6cm in the soft state is within the normal range. The length of the penis is related to congenital genetics, acquired development, nutritional status, geography, and individual differences. The development of the penis is mainly in puberty, if it is less than 4cm in the natural state, excluding other factors interference, then it may be short penis, if the penis length is shorter, which has an impact on sexual life, then it is necessary to pay attention to it, and need to be further examined, if there is a surgical indication, the penis length can be extended by surgery. Do not abuse drugs privately. In short, develop a positive mindset, correct understanding, if it has an impact on daily life, you need to actively treat.