Background/Objective Coffee chlorogenic acid has many health efficacies, such as anti-hypertension, anti-obese, anti-dementia, and improvement in skin properties. This study aims to evaluate the safety in the excessive dose of coffee chlorogenic acid for Japanese healthy adults.

Methods A randomized, double-blind, placebo-controlled trial was conducted in healthy Japanese adults. Eligible participants are healthy Japanese adults aged 20 to 60 years. Participants were randomly assigned to receive either the excessive dose of coffee chlorogenic acid or placebo for 4 weeks. The excessive dose of coffee chlorogenic acid (1,350 mg/day) is at five times the effective dose (270 mg/day). Safety was assessed by clinical chemistry, anthropometric measures, and adverse event reporting.

Results Twenty-six healthy adults were enrolled and randomized into two groups. This study analyzed all participants (n＝26). No adverse effects originating in the test or placebo diets were observed in the hematologic tests, blood biochemical tests, urine analysis tests, physical examination, or medical examination/history taking in all participants.

Conclusions The results provided that the excessive dose of coffee chlorogenic acid supplements is safe in healthy Japanese adults.

Trial registration University hospital Medical Information Network (UMIN) Clinical Trials Registry (UMIN-CTR) ID: UMIN000037230.