Do Japanese men's underwear sizes run small?

There is a difference in the underwear that the Japanese sell to the young and the old. The underpants for young people are made to be very skinny and small, in order to be taut and show young male beauty and sexiness. Just like jeans, the pants made for young men have very short gears and skinny legs. If the Chinese boys are not used to it, it is better to buy the L number is more appropriate.