Safety and tolerability of carvacrol in healthy subjects: a phase I clinical study

This study was designed to assess safety and tolerability of carvacrol in healthy individuals. Subjects were randomly divided into two groups receiving 1 and 2 mg/kg/day carvacrol. Before and after carvacrol administration, routine blood and urine laboratory tests and spirometry were performed for all participants. The results showed that one-month treatment with carvacrol did not significantly affect the measured variables. In the group receiving 1 mg/kg/day carvacrol, calcium, erythrocyte sedimentation rate (ESR), mean cell volume (MCV), hemoglobin (Hb), and hematocrit (HCT) levels were significantly reduced but creatinine phosphokinase (CPK) was significantly increased, after treatment compared to baseline values (p < 0.05-p < 0.001). There was significant reductions in high-density lipoprotein cholesterol (HDL), total bilirubin, amylase, iron, red blood cells (RBC) count, and HCT after one-month treatment with 2 mg/kg/day carvacrol compared to pretreatment values (p < 0.05-p < 0.01). Although, triglyceride (TG), phosphorus, lactate dehydrogenase (LDH), prothrombin time (PT), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) were significantly increased after treatment with carvacrol 1 mg/kg/day (p < 0.05-p < 0.001), all post-treatment measured parameters were within normal range. Treatment with carvacrol 2 mg/kg/day for one month increased FEV₁ (p < 0.05). Nevertheless, there was no significant difference in measured variables except LDH, MCH, MCHC, and MCV (p < 0.05-p < 0.01), between the two groups. The results of this phase I study regarding carvacrol effects on healthy subjects, showed clinical safety and tolerability for this agent.