What are the different lip shapes?
The science of lip prints is called cheiloscopy. This name came from the Greek word for lips.
Scientists say that human lips shapes are as unique as fingerprints. Therefore, in some cases they can be successfully used for personal identification. Truth be told - the pattern of wrinkles and lines on lips varies by individual.
Beauty perception is influenced by each individual's demographic background - as well as - by personal characteristics. However, objective measurements and ratios remain the foundation for aesthetic evaluations. Age, gender, country of residence, and profession significantly impact individual upper to lower lip ratio preferences. However, a 1:1 lip ratio can apparently be considered as the most pleasing one in the female face proportion.
In order to obtain a more accurate shape of lips or to reduce age changes, cosmetic surgery may be used. Lips mostly start to naturally reduce in size from the age of 28 years old onwards, as this is when collagen and hyaluronic acid production slows — the latter is the most commonly-used product in lip injection treatments. 
In some cases, lips reshaping is a surgical technique used to lift the lips and bring them into better proportion. Over time, aging of the mouth area results in elongation of the lip, change in skin texture, drooping of the corners, and loss of volume. Although fillers may address the volume issue, the shape of the lip is changed. Besides, such cosmetic elective procedures can be performed by the doctors from a variety of medical fields, including plastic surgeons.
Professional medical staff may help with the correction of lips shape, which is one of the most common issues addressed by cosmetic surgeons. Experienced team of Medical Travel Czech can provide both qualified consultation and prompt help to those who search to improve their own lip shape. According to the recent study which was carried across 35 countries - the perfect lip shape was all down to the symmetry. More than 60% of respondents thought a 1:1 ratio between the upper and lower lip was the most attractive shape. Some respondents witness a heavily-defined cupid's bow being the most-requested lip feature.
Correction of lips shape is recognised as one of the operations performed by cosmetic surgery professionals. In this case, as always, the procedures, techniques, and principles of cosmetic surgery are entirely focused on improving each patient’s appearance. It includes such aspects as an aesthetic appeal, symmetry, and proportion defined as the key goals. An aesthetic surgery can be performed on all areas of the head, neck, and body. Since cosmetic procedures treat areas that function properly, cosmetic surgery is designated as elective. 
Surprisingly enough, it is an universal ratio which applies to the proportion between upper to lower lip. So, in some cases, it can serve as an example for those who consider changing shapes of their own lips. Various scientific experiments were performed in order to test different lip ratios: they were achieved via digital alteration, enabling participants to change the ratio of a single female model's lips. Besides, demographic data sets were collected and analysis of variance was used to investigate respective lip ratio preferences. Again, the majority of survey takers ( approximately about 60%) chose the 1:1 lip ratio - as the most attractive proportion. No differences were found in respect to lip ratio preference and the self-reported ethnicity. However, interesting preferences prevailed when analyzing the subgroups regarding lower lip size.
It is also essential to specify the fact of patients opting for full and sumptuous shapes of lips. In general, these are the most preferable lip shapes of them all — however, according to another global survey, there would be the most meaningful key trait that distinguishes the perfect pouts from their equally plump, yet sub-par, counterparts. 
In any case, preliminary consulting and advice from highly trained doctors helps to identify pros and cons of undergoing any changes of lips’ shapes.
 Healthline: Different Lip Types...
 Research Gate: The Current Preferred Female Lip Ratio
 Insider: The Most Attractive Lip Shape according to Science