This study evaluated the safety of Belinal®, a dietary supplement made from silver fir (Abies alba) branch extract, in healthy volunteers. Fifteen adults took 900 mg of Belinal® daily for 14 days. Blood tests were performed at several time points to measure liver and kidney function (enzymes and other biochemical markers).

This was a prospective, open-label, single-arm interventional study conducted to assess the toxicological safety of Belinal®, a standardized water extract from silver fir (Abies alba) branches. Belinal® contains polyphenols, including lignans, flavonoids, and phenolic acids, which have demonstrated various pharmacological activities in previous studies.

The study enrolled 15 healthy volunteers (8 men, 7 women; age range 37-55 years). Participants received Belinal® capsules at a total daily dose of 900 mg (4 × 225 mg) for 14 consecutive days.

The study design included three consecutive two-week periods:

Wash-out period: to eliminate potential effects of prior supplement use. Comparative period: to assess natural variability in laboratory parameters without supplementation.

Test period: during which participants consumed Belinal® daily. Safety was evaluated by measuring liver and kidney biochemical parameters (AST, ALT, ALP, GGT, bilirubin, urea, creatinine, uric acid) at baseline, day 14, day 28, and day 42. Adverse events were monitored throughout the study.

Inclusion Criteria:

• Healthy adult volunteers
• Age 37-55 years
• Both sexes (male and female)
• Willingness to comply with study protocol and attend all study visits
• Signed informed consent

Exclusion Criteria:

• Known acute or chronic illness
• Use of any medications other than occasional analgesics (none were used by participants)
• Use of dietary supplements prior to or during the study
• Known mental illness (e.g., depression, psychosis, severe alcoholism, drug abuse)
• Consumption of more than 2 alcohol units per day (20 g ethanol, equivalent to ~2 dl wine, 5 dl beer, or 0.3 dl brandy)
• Participation in other research studies concurrently