First, thick lips and thin lips, the thickness of the lips refers to the thickness of the upper and lower red lips when the mouth is gently closed. Some people are divided into four categories according to the average thickness of the upper and lower layers:
① Small thin lips: the thickness is below 4 mm;
② Middle lip: 5 mm;
③ Thick lips: 9-12mm;
④ Thick convex lip: greater than 12mm.
Because the thickness of the upper and lower lips is not exactly the same, and the lower lip is usually thicker than the upper lip, some people think that,
The standard lips of women should be: upper red lip 8.2 mm, lower red lip 9. 1 mm, and male 2 ~ 3 mm..
The thickness of lips changes obviously with age. After the age of 25, especially after the age of 40, the thickness of lips can be significantly thinner.