Safety evaluation of silver fir (Abies alba) branch wood extract (Belinal®) in healthy human subjects

Silver fir ( Abies alba ) branch wood extract (Belinal ®​ ) is rich in bioactive polyphenols, particularly lignans, and has demonstrated various pharmacological effects, including cardioprotective, antiatherosclerotic, antidiabetic and antioxidant activities. Although the extract has a history of traditional use, its toxicological safety in humans has not yet been rigorously evaluated [ 1 ] [ 2 ]. This study aimed to assess the potential hepatotoxic and nephrotoxic effects of Belinal ®​ in healthy human subjects. Fifteen adult volunteers received 900 mg/day of the extract over a 14-day period. Liver and kidney function were monitored by measuring eight biochemical serum parameters (AST, ALT, gamma-GT, alkaline phosphatase, total bilirubin, urea, creatinine, uric acid) at three time points: baseline, pre-treatment, and post-treatment. No statistically significant changes were observed in any of the parameters during the test period. All values remained within the reference range, and no adverse events were reported. Although minor fluctuations were noted during the comparative period, these were not treatment-related and likely reflect normal physiological variability. The findings provide direct evidence that Belinal ®​ does not appear to adversely affect hepatic or renal function under the tested conditions, supporting its good safety profile as a food supplement. These results complement previous safety and effectivness data and contribute to the toxicological characterization of silver fir extracts for human use. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany