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Completed

NCT Number: NCT07189143

Silver Fir Safety in Healthy Volunteers

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).

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Key information

Conditions

Safety / Toxicology Dietary Supplement Healthy Volunteers Kidney Function Liver Function

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Ljubljana

Ljubljana, 1000, Slovenia

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Belinal® (Abies alba branch extract)

Dietary Supplement

Belinal® capsules, 900 mg/day (4 × 225 mg), orally for 14 consecutive days.

Primary outcomes

  1. Change in serum AST

    Time frame: Baseline, Day 14, Day 28, and Day 42.

    Change in aspartate aminotransferase (AST) to evaluate potential hepatotoxic effects. Unit of Measure: U/L

  2. Change in serum ALT

    Time frame: Baseline, Day 14, Day 28, Day 42.

    Change in alanine aminotransferase (ALT) to evaluate potential hepatotoxic effects. Unit of Measure: U/L

  3. Change in serum ALP

    Time frame: Baseline, Day 14, Day 28, Day 42.

    Change in alkaline phosphatase (ALP) levels to evaluate potential hepatobiliary effects. Unit of Measure: U/L

  4. Change in serum GGT

    Time frame: Baseline, Day 14, Day 28, Day 42.

    Change in gamma-glutamyl transferase (GGT) levels to evaluate potential hepatobiliary effects. Unit of Measure: U/L

  5. Change in serum bilirubin

    Time frame: Baseline, Day 14, Day 28, Day 42.

    Change in total bilirubin as a marker of liver function. Unit of Measure: µmol/L

  6. Change in serum urea

    Time frame: Baseline, Day 14, Day 28, Day 42.

    Change in blood urea levels as a marker of kidney function. Unit of Measure: mmol/L

  7. Change in serum creatinine

    Time frame: Baseline, Day 14, Day 28, Day 42.

    Change in serum creatinine levels as a marker of kidney function. Unit of Measure: µmol/L

  8. Change in serum uric acid

    Time frame: Baseline, Day 14, Day 28, Day 42.

    Change in uric acid levels as a marker of kidney function. Unit of Measure: µmol/L

Sponsors and collaborators

Lead sponsor

University of Ljubljana

Other

Registry information

Official study title

The Effect of Silver Fir Branch Extract on Liver and Kidney Function

Important dates

Study start
2018
Primary completion
2018
Study completion
2018
First posted
Sep 23, 2025
Registry last updated
Sep 23, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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