The fleshy part or “apple” of female cheeks contains more fat than the male and is therefore fuller and rounder – male cheeks are often quite hollow here. The width of the cheekbones is also about the same in men and women when compared to the distance between the eyes.
In my opinion the apple of the cheek is much more important for feminisation than the cheekbones. Hormones will add fat to the apple and in many cases TS women who are on hormones don't need any additional help here.
1. Fat Grafts:
If the apple of the cheeks needs to be fuller and more rounded you can have fat from another part of the body injected into the area (fat grafting). Using your own fat means that there is no risk of rejection or allergic reaction. There is some unpredictability involved as not all the fat will survive. The amount that survives varies from person to person and is quite unpredictable - the amount of fat that survives can be anywhere from about 30% to about 80%. So the surgeon will usually put in a little more than you need at first and will then top up as necessary a few months later.
The reason not all the fat survives is that when the surgeon removes the fat with liposuction (usually from the abdomen) some of the fat cells are ruptured. There is currently no way round this – if you cut out the fat in larger chunks it leaves scars and doesn't survive well either so liposuction followed by injection of the fat is still the best option.
2. Solid Implants:
Cheek bones can be enhanced either with solid implants or a bone-filler paste. Solid implants are available in several shapes and can be placed over or under the cheekbone or lower down near the sides of the nose according to the needs of the patient. Bone-filler is moulded to the desired shape in situ and sets solid, eventually becoming part of the bone. The Incisions for these techniques are usually made inside the mouth up in the gums.
In the majority of cases it is best to give hormones plenty of time to work on your cheeks (a year or so on a full dose in my opinion) before you consider cheek augmentation. An FFS surgeon should ask about your hormone status before they recommend cheek augmentation! And they should not recommend procedures to fill the apple of your cheeks until the hormones have had a chance to work. There may be exceptions to this where there is a clear problem with your cheekbones that can be corrected at any stage in your hormonal treatment but as a good rule, do give the cheeks a chance to feminise before you try to alter them surgically.
The 2 creases that come down from the corners of the nose past the corners of the mouth are called "naso-labial folds". Both males and females can have these lines and they tend to get deeper with age. Filling or reduction of the naso-labial folds is sometimes offered as part of FFS but as far as I can see it has no feminising effect but it has a mildly rejuvenating effect in some cases.
Cheek implants are inserted through the gum line inside the mouth and as this area is full of bacteria, there is always an infection risk no matter how scrupulous the surgeon is. Cheek implants can also slip but the main problem I come across is when they show through the soft tissue as unnatural looking lumps.
Fat transfers to the cheeks are less prone to infection and there is no risk of rejection as it is your own fat. However, the fat can be put in unevenly or unevenness could develop if the fat is reabsorbed at different rates.
It is quite widely believed that male faces are actually a little wider across the cheekbones than female faces but this is misleading for FFS purposes. Technically it is true if you compare the width across the cheekbones to the width of the cranium (the round part of the skull). However the width of the cranium is only something you can see when someone is bald or has a shaved head - in the vast majority of cases, the width of a woman's cranium is hidden by her hair and even if it wasn't, I don't think this is an area that our brains use for gender recognition. There is also confusion because sometimes a reference to the “width” of the cheeks in some scientific papers is not about the distance across the cheekbones, but about the thickness of the cheekbone itself.