Background and Purpose: Glycerin is a common pharmaceutical excipient derived from petroleum. Plant-based glycerin can be derived from oilseeds thus offering an alternative from renewable feedstocks. These excipients may contain trace amounts of glycerol acetate compounds such as 1-monoacetin and 2-monoacetin. A safety assessment was conducted to support the use of plant-based glycerin for excipient use. Methods: Safety of 1-monoacetin and 2-monoacetin was investigated using a weight of evidence approach based on a literature search, QSAR, and read-across approaches. Data generated using in silico methods were confirmed by standardized in vitro genotoxicity testing, using a mixture containing 91% 1-monoacetin and 7.6% 2-monacetin. The test material was purified from a mixture of monoacetin, diacetin, and triacetin using column chromatography. Genotoxicity of this mixture was tested using a bacterial mutagenicity test designed according to OECD test guideline 471 and in an in vitro micronucleus screening assay conducted in human TK6 lymphoblast cells in general accordance with OECD test guideline 487. Results: Both 1-monoacetin and 2-monacetin were predicted to undergo hydrolysis by carboxylesterases into glycerin and acetic acid. Literature data demonstrated a low hazard potential for glycerin and acetic acid based on robust toxicology datasets. The literature search on 1-monoacetin identified a positive bacterial mutagenicity test, a negative in vitro chromosomal aberration assay, and a positive sister chromatid exchange (SCE) assay. These bacterial mutagenicity results were achieved at excessive doses and merited further investigation, whereas the SCE assay lacks mutagenic predictivity. 2-monoacetin was predicted to be non-mutagenic by QSAR analysis. A mixture of 1-monoacetin and 2-monacetin was negative for bacterial mutagenicity with or without S9 activation at doses of up to 5 mg/plate. This mixture was also negative for clastogenicity with or without S9 activation in an in vitro micronucleus screening assay when tested at doses of up to 10mM. Conclusions: The weight of evidence evaluation supported the safety profile of 1-monoacetin and 2-monacetin. The mixture of 1-monoacetin and 2-monoacetin was not mutagenic or clastogenic when evaluated by bacterial mutagenicity and in vitro micronucleus assays, respectively. These results are consistent with the lack of general toxicity or genotoxicity of the shared metabolites for these compounds, glycerin and acetic acid.