ScopeTo assess bioavailability of terpenes in human plasma and their effect on oxidative stress biomarkers.Methods and resultsIn this open‐label and single arm postprandial trial, seventeen healthy male volunteers (20–40 years old) follow a low‐phytochemical diet for 5 days. Next, after overnight fasting, volunteers consume Mastiha powder (a natural resin rich in terpenes) dispersed in water. Blood samples are collected on time points 0 h (before ingestion) and 0.5, 1, 2, 4, 6, and 24 h (post‐ingestion). Ultra‐high‐pressure liquid chromatography high‐resolution MS (UHPLC‐HRMS/MS) is applied for high throughput analysis of plasma. Serum resistance to oxidation and oxidized LDL (oxLDL) levels are measured. UHPLC‐HRMS/MS analysis shows that major terpenes are bioavailable since 0.5 h after administration, reaching a peak between 2 h and 4 h. Serum resistance to oxidation, expressed as difference of tLAG (time point‐0 h), starts to increase from 0.5 h. This increase reaches statistical significance at 4 h (402.3 ± 65.0 s), peaks at 6 h (524.6 ± 62.9 s), and remains statistically significant until 24 h (424.2 ± 48.0 s). oxLDL levels, expressed as %change from 0 h, are reduced significantly from time point‐1 h until time point‐6 h.ConclusionResults demonstrate the terpene bioavailability pattern after oral administration of Mastiha. Terpenes are potential mediators of antioxidant defense in vivo.