Is 20cc a reasonable amount for entire face fat transfer?

It all depends on what you're trying to achieve. Fat can be injected into the cheeks, brows, temples, nasolabial folds, chins, lips, really anywhere that needs volume!  For a full face rejuvenation, I think it's a good amount, because it's important to remember that 25-30% of it gets resorbed by the body, so you do have to "over inject" today in order to achieve the desired result several weeks from now. This is why you need an experienced injector, one who can asses you and properly predict what you're going to need. Fat is superior to commercially produced fillers because not only does it provide volume, it also brings with it stem cells, and all the benefits they provide, fresher skin, healthier tissue, etc. With regards to repeat treatments, there is no set time frame. Everyone ages differently. It could be a year, it could be 5 years before you need your next treatment.  The key is maintaining good follow up appointments with your doctor. I wish you the best!

Thank you for your questions. With fat grafting, there is no standard by which to measure. It depends on the deficiencies you had and the areas you were trying to treat and how much. As well as the fact that some of the fat will absorb so cautious over-correction is usually appropriate. Depending on how many ares were treated (everyone has a different definition of "full face"), I do not think 20 cc is an unreasonable number....I have done more and I have done less. As for repeating a treatment, I would wait at least 12-18 months before repeating facial fat grafting. Good luck!

if the fat is properly spun down and concentrated at the appropriate centrifuge speed, I feel that 20 mL injected into the face should be sufficient. 

Fat Transfer is a great procedure and it is different in every patient.  The amount that is needed depends on the areas that will be injected.  The volume that is needed for each face depends on the patient's individual anatomy, and what is youthful for that face.  And, each patient is unique.  20cc's may be the right amount for your face.  This is determined at the time of surgery.  The benefit of fat transfer is the added volume as well as the transfer of stem cells which enrich the skin as well.  This is the added benefit of doing fat transfer.I hope this helps.

Every patient is different. I have put in as little as 10-20 cc's and as much as 50-60cc's. It all depends upon the individual

Good Day. Thank you for your excellent question.Facial fat transfer is patient specific, each of us being unique. The variables that a surgeon takes into consideration is the number of anatomic areas to be augmented, the amount of volume loss per area for both volume correction and facial symmetry, and the underlying patients medical condition (cardiac disease, steroid use, smoking, diabetes- all lower the fat survival rate).Some patients desire only one or two areas of fat and others the entire face. The most fat volume I have placed in a man in my career was about 100 cc and in a woman 80 cc, however, the average amount of grafted purified fat has ranged from 35-65 cc in most patients.Fat grafting is one of the most diverse surgical techniques among surgeons than any other surgical procedure. This is the reason comparable studies to determine the best method of fat transfer is difficult. For instance, there are different techniques for each step: harvesting (about 7 different methods), fat processing (about twenty different methods), enrichment (PRP and stem cells- each with different methods to acquire the substance), fat administration (numerous cannula injection techniques to improve outcomes and fat survival). Optimizing each step is imperative. Doing basic science along with clinical research helps determine the Best Technique. By using fat cell and stem cell testing of numbers and viability and bacterial contamination can be used directly with clinical volume assessment by photographs, diagnostic ultrasound and magnetic imaging as well as in person examination. Summarizing, the amount of fat to be grafted to one's face or any other anatomical area is patient specific, customized to each individuals appearance. Best of luck.

Unfortunately there is no simple answer to your question.  Microfat transfer varies greatly from patient to patient based on individual needs.  Without having seen you it is difficult to say if a 20 cc volume is adequate for you.  Some patients may require more and others less just depending on how much volume they have lost over the years.
I would recommend waiting about 6 months and then following up with your doctor to discuss the results.  Sometimes a second procedure is warranted and will enhance the results.  
Regardless of whether or not you need more, I think you made a wise decision going with microfat transfer.  Not only does the fat provide volume, but the stem cells that come along with it help to improve the skin itself.