The Effects of Geranylgeraniol Supplementation on Testosterone in Middle-Aged Healthy Adults: An 18-Week, Single-Group Crossover Placebo-Controlled Trial.

Background: Geranylgeraniol (GG) is a naturally occurring isoprenoid that is involved in steroid hormone synthesis, the endogenous production of coenzyme Q10 (CoQ10), healthy muscle function, bone metabolism, and cellular energy production. Although preclinical research and a recent human study have...

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Publicado en:Integrative Medicine: A Clinician's Journal Vol. 25; no. 2; pp. 12 - 20
Autores principales: Jurgelewicz, Michael, D'Adamo, Christopher R., Malaya, Christopher A.
Formato: clinical trial research tables/charts Journal Article
Publicado: InnoVisions Professional Media Apr2026
Acceso en línea:Ver este registro en EBSCOhost
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      dt: Apr2026
      vid: 25
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      pub: InnoVisions Professional Media
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        atl: The Effects of Geranylgeraniol Supplementation on Testosterone in Middle-Aged Healthy Adults: An 18-Week, Single-Group Crossover Placebo-Controlled Trial.
      aug:
        au:
          Jurgelewicz, Michael
          D'Adamo, Christopher R.
          Malaya, Christopher A.
        affil: Human Nutrition Institute, University of Bridgeport, CT, USA
      sug:
        subj:
          Hydrocarbons Therapeutic Use
          Hydrocarbons Pharmacodynamics
          Dietary Supplementation
          Testosterone Drug Effects
          Coenzyme Q Drug Effects
          Sexual Health Evaluation
          Treatment Outcomes Evaluation
          Human
          Male
          Female
          Middle Age
          Crossover Design
          Placebos Therapeutic Use
          Control Group
          Clinical Trials
          Patient Compliance
          Monitoring, Physiologic
          Self Report
          Blood Specimen Collection
          Liquid Chromatography-Mass Spectrometry Methods
          Clinical Assessment Tools
          Scales
          Paired T-Tests
          Repeated Measures
          Analysis of Variance
          Post Hoc Analysis
          Questionnaires
          Effect Size
          Data Analysis Software
          Funding Source
          Middle Aged: 45-64 years
          Male
          Female
      ab: Background: Geranylgeraniol (GG) is a naturally occurring isoprenoid that is involved in steroid hormone synthesis, the endogenous production of coenzyme Q10 (CoQ10), healthy muscle function, bone metabolism, and cellular energy production. Although preclinical research and a recent human study have indicated a potential role for GG in modulating testosterone levels, its effects in middle-aged adults remain unclear. Aim: This study aimed to assess the effects of GG supplementation on testosterone status, coenzyme Q10 concentrations, and validated questionnaires of overall and sexual health in middle-aged healthy adults. Method: This 18-week, single-group, crossover, placebo-controlled trial involved participants aged 40 to 65 years. The intervention consisted of 8 weeks of placebo followed by a 2-week washout and 8 weeks of GG supplementation (300 mg/day). Outcomes were assessed at baseline, Week 8 (after blinded placebo), Week 10 (post-washout), and Week 18 (after blinded intervention). Results: Thirty-four participants completed the study. No significant changes were observed in total testosterone, free testosterone, or sex hormone binding globulin (all P > .05) in the full study sample or within the female subgroup. In the subgroup of men with lower baseline testosterone (<600 ng/dL, n = 8), total testosterone increased significantly following GG supplementation (mean difference = 28.44 ng/dL, 95% CI: 7.45--49.43, P = .015), with a large effect size (Cohen's d = 1.13), indicating a meaningful physiological response. Serum CoQ10 declined significantly during placebo (mean difference = -0.10 µg/mL, P = .03) but remained stable during GG supplementation (P = .9), suggesting a potential maintenance effect. Conclusion: These results highlight GG as a promising natural strategy to support endogenous testosterone production and CoQ10 homeostasis in age-related declines. Further investigation in larger, targeted populations such as men with late-onset hypogonadism or individuals on statin therapy is warranted.
      pubtype: Academic Journal
      doctype:
        clinical trial
        research
        tables/charts
        Journal Article
      ougenre: Article
    language: English
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