What size are normal testicles for adults?

Patient's question:

I recently don't know why my lower body feels very uncomfortable, and I also don't have morning erections anymore. Please ask, what size of testicles in adults is considered normal

Doctor's answer:

The testes are located in the scrotum, with one on each side, generally slightly lower on the left by 1 cm. In adults, the testes are 3.5-4.5 cm long, 2-3 cm wide, and 1-2 cm thick, with each testis weighing 10-15 grams.
According to your symptoms, it is mainly caused by kidney essence deficiency, leading to premature ejaculation and impotence. Treatment should focus on replenishing kidney essence, strengthening the kidneys, and consolidating them. You can take Jin Suo Gu Jing Wan (Golden Lock Consolidating Essence Pill) and Wu Zi Yan Zong Wan (Five Seeds Originating Pill) for treatment.