What the research shows
How much fat stays. Pooled studies that measured volume found that just under half of the injected fat remained, with a wide range from patient to patient, and the method of measurement changed the figure (Lv 2021, Gornitsky 2019). On ultrasound, volume falls over the first three to six months and then holds steady (Ouyang 2026). A second session tended to keep more than the first (Lv 2021). For a patient this means planning for some loss and possibly a touch-up.
Where it works best. In reconstructive patients, fat in the cheeks gave good results far more often than fat in the lips, where results were weakest (Mojallal 2009).
How the fat is prepared. In a randomized trial, fat cleaned by filtering through cotton pads kept more volume at a year than spun or settled fat (Wu 2018). Adding stromal vascular fraction, a concentrate of the support and stem cells found in fat, improved retention in randomized trials (Gontijo-de-Amorim 2017, Wufuer 2024). Platelet-rich fibrin did not change how much fat stayed in the temples but shortened recovery (Zhang 2022).
Nanofat and skin quality. Nanofat is fat broken up and filtered until no living fat cells remain, while stem cells survive; it passes through very fine needles and was first used for fine wrinkles, scars and dark lower lids (Tonnard 2013). Scar studies show improvement, mostly in the short term (Tran 2024, Al-Sabri 2025). For general skin quality, studies report better texture and color, but the evidence is weak and the effect small (van Dongen 2019).
Safety. Pooled reviews report complications in fewer than three patients in 100, most often asymmetry (Gornitsky 2019, Lv 2021), though many studies do not report problems at the treated site, so the true rate is unknown (Schiraldi 2022). The rare, serious event is fat entering an artery and travelling to the eye or brain: every reported patient with a blocked eye artery lost vision permanently, and some died (Moellhoff 2023). Most severe events followed injection into the forehead and temples (Brucato 2024). The authors advise care with the anatomy of these areas.
Where surgeons disagree
- Filtering or spinning. One randomized trial favored filtration (Wu 2018); a split-face trial found filtered and spun fat gave the same result at a year (Botti 2011).
- Enriching the fat. Small trials show better retention with added cells (Wufuer 2024), but a review of all supplements rated most studies weak and found the benefit unclear (Schipper 2022).
- Fat or filler. Pooled studies lean toward higher satisfaction with fat, likely because it lasts, but results varied too widely to be sure; filler can be dissolved and is more convenient (Hassan 2026).
What is new
- Ultrasound now maps facial vessels and guides the cannula into safe layers; studies using it reported no blindness, stroke or skin loss (Ouyang 2026).
- Experts agreed on a standard way to make nanofat, so studies can compare like with like (Arcani 2025).
- Higher-quality scar trials found no lasting benefit from nanofat beyond a year (Al-Sabri 2025).
What is still unknown
- The true complication rate, since reporting is incomplete (Schiraldi 2022).
- How to treat fat in an artery once it happens; there is no evidence-based plan (Moellhoff 2023).
- Whether any additive reliably helps fat survive (Schipper 2022).
Key papers
- Lv 2021: pooled how much facial fat survives.
- Gornitsky 2019: retention and complication rates across facial fat grafting.
- Mojallal 2009: results depend on the part of the face treated.
- Tonnard 2013: introduced nanofat for skin.
- Wu 2018: compared three ways to prepare fat in a randomized trial.
- Gontijo-de-Amorim 2017: stem cell enrichment kept more volume.
- Moellhoff 2023: the outcomes of fat entering an artery.
- Brucato 2024: forehead and temples carry most severe complications.