Concerns have been raised regarding the safety of angiotensin converting enzyme 
inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) in patients with 
coronavirus disease of 2019 (COVID-19), based on the hypothesis that such 
medications may raise expression of ACE2, the receptor for severe acute 
respiratory syndrome-coronavirus 2 (SARS-CoV-2). We conducted a literature 
review of studies (n = 12) in experimental animals and human subjects (n = 12) 
and evaluated the evidence regarding the impact of administration of ACEIs and 
ARBs on ACE2 expression. We prioritized studies that assessed ACE2 protein 
expression data, measured directly or inferred from ACE2 activity assays. The 
findings in animals are inconsistent with respect to an increase in ACE2 
expression in response to treatment with ACEIs or ARBs. Control/sham animals 
show little to no effect in the plurality of studies. Those studies that report 
increases in ACE2 expression tend to involve acute injury models and/or higher 
doses of ACEIs or ARBs than are typically administered to patients. Data from 
human studies overwhelmingly imply that administration of ACEIs/ARBs does not 
increase ACE2 expression. Available evidence, in particular, data from human 
studies, does not support the hypothesis that ACEI/ARB use increases ACE2 
expression and the risk of complications from COVID-19. We conclude that 
patients being treated with ACEIs and ARBs should continue their use for 
approved indications.