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This study will evaluate the effects of daily geranylgeraniol (GG) supplementation on muscular strength, body composition, and aerobic capacity in healthy, physically active men and women. Approximately 60 participants aged 30-60 years will be enrolled in a randomized, double-blind, placebo-controlled, parallel-group trial lasting 8 weeks.
Participants will be assigned to receive either placebo, 150 mg GG, or 300 mg GG daily. Outcome measures will be assessed at baseline, week 4, and week 8 and include maximal strength (1RM bench press and leg press), fat-free mass, muscular endurance, aerobic capacity (VO2peak), and circulating biomarkers related to metabolism and health.
This study is a randomized, double-blind, placebo-controlled, parallel-group trial designed to examine the dose-response effects of geranylgeraniol (GG) supplementation on muscular strength, body composition, aerobic capacity, and physiological biomarkers in healthy, physically active adults.
Approximately 60 men and women aged 30-60 years will be recruited and randomized, stratified by sex, age, and baseline fat-free mass, to receive one of three interventions: placebo, 150 mg GG, or 300 mg GG daily for 8 weeks. All participants and study personnel will remain blinded to group allocation throughout the study.
Participants will complete a screening visit followed by testing visits at baseline (week 0), week 4, and week 8. Assessments will include maximal strength testing (1RM bench press and leg press), muscular endurance (repetitions to failure at a fixed percentage of 1RM), aerobic capacity (VO2peak via graded treadmill test), and body composition using a four-compartment model derived from dual-energy X-ray absorptiometry (DEXA) and bioelectrical impedance spectroscopy.
Venous blood samples will be collected to assess coenzyme Q10, sex steroid hormones, inflammatory markers, and clinical safety parameters including complete blood count, comprehensive metabolic panel, and lipid profile. Additional outcomes include mood and quality of life assessed via validated questionnaires (POMS and SF-36), dietary intake via 4-day food logs, and fecal samples for metabolomic analysis.
The primary endpoints are changes in maximal strength (1RM leg press and bench press) and fat-free mass from baseline to week 8. Secondary endpoints include changes in muscular endurance, aerobic capacity, body composition variables, biochemical markers, and patient-reported outcomes. Safety will be monitored throughout the study via clinical labs and adverse event reporting.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Placebo Comparator | Placebo Comparator | Participants will ingest a placebo consisting of olive oil daily for 8 weeks. The supplement will be consumed with approximately 8 ounces of water at a consistent time each day. |
|
| 150 mg Geranylgeraniol | Active Comparator | Participants will ingest 150 mg of geranylgeraniol (GG) daily for 8 weeks. The supplement will be consumed with approximately 8 ounces of water at a consistent time each day. |
|
| 300 mg Geranylgeraniol | Active Comparator | Participants will ingest 300 mg of geranylgeraniol (GG) daily for 8 weeks. The supplement will be consumed with approximately 8 ounces of water at a consistent time each day. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Dietary Supplement - Placebo | Dietary Supplement | Participants will ingest a placebo consisting of olive oil daily for 8 weeks. The supplement will be consumed with approximately 8 ounces of water at a consistent time each day. |
| Measure | Description | Time Frame |
|---|---|---|
| Leg Press One-Repetition Maximum (1RM) | Maximal lower-body strength will be assessed as leg press one-repetition maximum (1RM), defined as the greatest load that can be lifted for one complete repetition using proper technique. | Change from baseline (Week 0) to Week 8 |
| Bench Press One-Repetition Maximum (1RM) | Maximal upper-body strength will be assessed as bench press one-repetition maximum (1RM), defined as the greatest load that can be lifted for one complete repetition using proper technique. | Change from baseline (Week 0) to Week 8 |
| Fat-Free Mass | Fat-free mass will be assessed using a four-compartment body composition model derived from dual-energy X-ray absorptiometry (DEXA) and bioelectrical impedance spectroscopy (BIS). | Change from baseline (Week 0) to Week 8 |
| Measure | Description | Time Frame |
|---|---|---|
| Leg Press Muscular Endurance | Lower-body muscular endurance will be assessed as the number of repetitions completed to failure on the leg press using a load corresponding to 80% of the participant's baseline leg press 1RM. | Change from baseline (Week 0) to Week 8 |
| Bench Press Muscular Endurance |
| Measure | Description | Time Frame |
|---|---|---|
| Resting Heart Rate | Resting heart rate will be assessed under standardized resting conditions. | Change from baseline (Week 0) to Week 8 |
| Resting Blood Pressure | Resting blood pressure will be assessed under standardized resting conditions. |
Inclusion Criteria:
Exclusion Criteria:
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| Name | Role | Phone | Extension | |
|---|---|---|---|---|
| Anthony M Hagele, MS | Contact | 6369494785 | ahagele@lindenwood.edu | |
| Joesi M Morey, MS | Contact | 6168266008 | jmorey@lindenwood.edu |
| Name | Affiliation | Role |
|---|---|---|
| Chad M Kerksick, PhD | Lindenwood University | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| Lindenwood University Exercise and Performance Nutrition Laboratory | Recruiting | Saint Charles | Missouri | 63301 | United States |
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| ID | Term |
|---|---|
| C017338 | geranylgeraniol |
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Participants will be randomized to one of three parallel groups to receive either placebo, 150 mg geranylgeraniol (GG), or 300 mg geranylgeraniol (GG) daily for 8 weeks. Randomization will be stratified by sex, age, and baseline fat-free mass. All groups will follow the same testing schedule and procedures throughout the study period.
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This study will employ a double-blind design in which participants, investigators, and study personnel involved in data collection and outcome assessment are blinded to group assignment. Supplements will be prepared in identical form and appearance and coded by an independent party not involved in data collection or analysis. Group assignments will remain concealed until completion of data collection and primary analyses.
| Geranylgeraniol (150 mg) | Dietary Supplement | Participants will ingest 150 mg of geranylgeraniol (GG) daily for 8 weeks. The supplement will be consumed with approximately 8 ounces of water at a consistent time each day. |
|
| Geranylgeraniol (300 mg) | Dietary Supplement | Participants will ingest 300 mg of geranylgeraniol (GG) daily for 8 weeks. The supplement will be consumed with approximately 8 ounces of water at a consistent time each day. |
|
Upper-body muscular endurance will be assessed as the number of repetitions completed to failure on the bench press using a load corresponding to 80% of the participant's baseline bench press 1RM. |
| Change from baseline (Week 0) to Week 8 |
| Peak Oxygen Consumption (VO2peak) | Aerobic capacity will be assessed as peak oxygen consumption (VO2peak) during a graded treadmill exercise test. | Change from baseline (Week 0) to Week 8 |
| Fat Mass | Fat mass will be assessed using dual-energy X-ray absorptiometry (DEXA) and bioelectrical impedance spectroscopy (BIS). | Change from baseline (Week 0) to Week 8 |
| Percent Body Fat | Percent body fat will be assessed using dual-energy X-ray absorptiometry (DEXA) and bioelectrical impedance spectroscopy (BIS). | Change from baseline (Week 0) to Week 8 |
| Total Body Water | Total body water will be assessed using bioelectrical impedance spectroscopy (BIS). | Change from baseline (Week 0) to Week 8 |
| Intracellular Water | Intracellular water will be assessed using bioelectrical impedance spectroscopy (BIS). | Change from baseline (Week 0) to Week 8 |
| Extracellular Water | Extracellular water will be assessed using bioelectrical impedance spectroscopy (BIS). | Change from baseline (Week 0) to Week 8 |
| Plasma Coenzyme Q10 Concentration | Plasma coenzyme Q10 concentration will be assessed from venous blood samples. | Change from baseline (Week 0) to Week 8 |
| Serum Testosterone Concentration | Serum testosterone concentration will be assessed from venous blood samples. | Change from baseline (Week 0) to Week 8 |
| Serum Estrogen Concentration | Serum estrogen concentration will be assessed from venous blood samples. | Change from baseline (Week 0) to Week 8 |
| Serum Progesterone Concentration | Serum progesterone concentration will be assessed from venous blood samples. | Change from baseline (Week 0) to Week 8 |
| Profile of Mood States (POMS) Score | Mood state will be assessed using the Profile of Mood States (POMS) questionnaire. | Change from baseline (Week 0) to Week 8 |
| RAND SF-36 Score | Health-related quality of life will be assessed using the RAND SF-36 questionnaire. | Change from baseline (Week 0) to Week 8 |
| Fecal Metabolomic Profile | Fecal metabolomic outcomes will be assessed from self-collected stool samples. | Change from baseline (Week 0) to Week 8 |
| Change from baseline (Week 0) to Week 8 |