Fat graft (FG) absorption rate varies from 20 to 80% in two years. Recently, several bioengineering techniques were applied to improve FG retention rate. Numerous studies investigated the use of adipocyte-derived stem cells (ASC) as FG enrichment. However, ASC production is costly, complex, and time-consuming. In contrast, Nanofat, a combination of lipids, stem cells and growth factors, offers a faster, simpler, and more cost-effective alternative for FG enrichment. This study aims to compare the effects of ASC with those of Nanofat, as a viable option in FG enrichment. Animals were allocated in three groups: Control group (1mL fat), ASC group (1mL fat +1x106ASC), andNnF group (1mL of fat + 0.3mL NnF). These groups were subdivided in three subgroups (4, 8, and 12 weeks, n = 6/group). We performed ultrasound and macroscopic measurements for FG volume, histology and expression of healing and inflammation genes. At week 12, ASC and NnF groups showed a higher retention of FG when compared to the Control group (51%, 46%, 12% respectively, p < 0.01). Fibrosis was similar in ASC and Nanofat groups. The Nanofat group showed a higher vascular density then the Control group (p < 0.05). Il-10 gene expression was higher, and Mmp9 was lower in the Nanofat group when compared to the ASC and Control groups. This study indicates that enriching FG with both ASC and Nanofat led to an increased retention rate of the FG, suggesting that Nanofat might be a promising alternative for FG enrichment. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .