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A Crossover Clinical Trial Investigating the Effects of Geranylgeraniol (GG) Supplementation on Testosterone Levels in Healthy Men and Women Over an 18-week Period

A Crossover Clinical Trial Investigating the Effects of Geranylgeraniol (GG) Supplementation on Testosterone Levels in Healthy Men and Women Over an 18-week Period

Status
Completed
Phases
Unknown
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT06747624
Enrollment
34
Registered
2024-12-24
Start date
2025-01-30
Completion date
2025-09-19
Last updated
2026-05-01

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Health, Wellness

Keywords

Geranylgeraniol, GG

Brief summary

The primary purpose of this study is to investigate the effects of geranylgeraniol (GG) supplementation on testosterone levels in middle-aged (40 to 65 years) healthy men and women. The research team hypothesizes that geranylgeraniol (GG) supplementation will enhance testosterone levels and improve self-reported health outcomes in a healthy population.

Detailed description

The proposed study is an 18-week crossover, placebo-controlled pilot study of GG supplementation or placebo. All study outcomes will be measured at baseline (the beginning of the first week) and at the conclusion of the first 8-week period. This will be followed by a 2-week washout period; study procedures will be repeated with the second intervention for an additional 8 weeks. Outcomes will be assessed at the beginning of this period, and the end, in the same manner as for the first 8-week block. All participants will receive a placebo (300 mg medium chain triglycerides/daily) or gernaylgeraniol supplementation (300 mg GG/daily). Subjects will be required to fast for 8 hours with no alcohol consumption before their blood draw. Baseline blood samples will be drawn before administering one of two treatments with subsequent blood samples to be drawn in the morning (between 7 am and 8 am) at 8, 10, and 18 weeks. Each participant will take the assigned intervention daily with breakfast for the following 8 weeks. After a 14-day washout period, this process will be repeated for the remaining treatment. Self-reported height and weight will be obtained to calculate body mass index (BMI). Questionnaires on overall health (SF-36) and sexual health \[PROMIS Sexual Function and Satisfaction (SexFS) v2.0 Brief Profile (Male/Female)\] will be assessed at baseline, 8, 10, and 18 weeks. All laboratory testing will occur at a LabCorp patient service center. The serum samples will be analyzed for Free and Total Testosterone using liquid chromatography with tandem mass spectrometry (LC-MS-MS). LabCorp test code: 070195; Serum Sex Hormone-Binding Globulin (SHBG) will be analyzed using Electrochemiluminescence immunoassay (ECLIA). LabCorp test code: 082016. Coenzyme Q10, Total (CoQ10). LabCorp test code: 120251.

Interventions

DIETARY_SUPPLEMENTGeranylgeraniol 300 mg

300 mg of trans-geranylgeraniol (GG)

DIETARY_SUPPLEMENTPlacebo

300 mg medium chain triglycerides

Sponsors

Designs for Health
Lead SponsorINDUSTRY

Study design

Allocation
NON_RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
OTHER
Masking
SINGLE (Subject)

Eligibility

Sex/Gender
ALL
Age
40 Years to 65 Years
Healthy volunteers
Yes

Inclusion criteria

1. Males and females between 40 to 65 years of age. 2. Individuals with no significant history of inflammatory bowel disease (i.e. ulcerative colitis, Crohn's, Celiac, etc.), ulcers, liver and/or kidney disease or other any acute or chronic dis-ease. 3. Ability to read and speak English 4. Subject's agreement to voluntarily participate in the study 5. Negative pregnancy test confirmed with serum HCG on initial baseline testing and baseline testing at the start of the crossover (at 10 weeks)

Exclusion criteria

1. Males and females under 40 or over 65 years of age 2. Previous (in the past 60 days) or current hormone replacement therapy 3. Males and females with free testosterone levels over normal range 4. History of hysterectomy, oophorectomy, or orchiectomy 5. Current biotin supplementation \>3 mg per day one week prior to the start of the study 6. Current or history of smoking 7. CoQ10/Ubiquinol supplementation within the past 2 weeks 8. Current use of hormone boosting supplements (i.e. fenugreek, shilajit, tongkat ali, ashwagandha) within the past 4 weeks 9. Current or previous use of medication - NSAIDS, statins, blood thinners, H2 blockers and PPI or blood sugar-lowering agents. 10. Diabetes 11. Cancer 12. Hemophilia 13. Disorders of heart, kidney, lung or liver function 14. Infectious diseases 15. Alcohol or drug abuse (\>7 drinks per week for men and women) 16. Pregnancy, lactation, or individuals planning to become pregnant in the next 6 months 17. Failure to submit statement of consent 18. Participant in a clinical trial in the previous 30 days.

Design outcomes

Primary

MeasureTime frameDescription
Serum Total Testosterone (LC/MS-MS)Baseline, 8 weeks, 10 weeks, and 18 weeksCan aid in the diagnosis of androgen dysfunction in men and women and is more specific method of measuring testosterone concentrations. Units in ng/ml.
Serum Free Testosterone (Direct)Baseline, 8 weeks, 10 weeks, and 18 weeksThe concentration of unbound testosterone in serum. The majority of serum total testosterone is associated with sex hormone binding globulin (SHBG) and this fraction is tightly bound and bio-logically unavailable to its target tissues. The remaining bioavailable testosterone is mostly bound to albumin, with only a small fraction circulating in the free form. Free testosterone is the form of testosterone that can diffuse into the tissues and act on receptors and is considered the active fraction. Free testosterone assessment is recommended as a primary or secondary measure of androgen activity in men and women. Units in pg/ml.

Secondary

MeasureTime frameDescription
Serum Sex Hormone Binding Globulin (SHBG)Baseline, 8 weeks, 10 weeks, and 18 weeksThe blood transport protein for testosterone and estradiol. SHBG binds reversibly to sexual steroids and is an important indicator of an excessive/chronic androgenic action where androgen levels are normal, but where clinical symptoms would seem to indicate androgen in excess. SHBG is a useful supplementary parameter in the determination of androgen where a high concentration of free androgen (i.e., testosterone) is suspected. Reference ranges in men: 20-49 years: 16.5-55.9 nmol/L; \>49 years: 19.3-76.4 nmol/L. Reference ranges in women: 20-49 years: 24.6-122.0 nmol/L; \>49 years: 17.3-125.0 nmol/L.
Coenzyme Q10 (CoQ10)Baseline, 8 weeks, 10 weeks, and 18 weeksCoQ10 is endogenously synthesized via the mevalonate pathway and some is obtained in the diet from meat products. It is also a powerful lipid-soluble antioxidant protecting cell membranes and lipoproteins. Reference range: 0.37-2.20 µg/mL.
SF-12- Health SurveyBaseline, 8 weeks, 10 weeks, and 18 weeksThe SF-12 (Short Form Health Survey) is an indicator of overall health status across eight scales: physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, and mental health.
PROMIS- Sexual Health and SatisfactionBaseline, 8 weeks, 10 weeks, and 18 weeksSexual health \[PROMIS Sexual Function and Satisfaction (SexFS) v2.0 Brief Profile (Male) and (Female)\]. The SexFS assesses interest in sexual activity. These are domains relevant to healthy individuals.

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: May 2, 2026