The purpose of this study is to investigate the pharmacokinetic properties of icariin, an active ingredient in the over-the-counter supplement, Horny Goat Weed.

The purpose of this study is to investigate the pharmacokinetic properties of icariin, an active ingredient in the over-the-counter supplement, Horny Goat Weed.

Healthy volunteers will be randomly assigned to a 5 day course of icariin at 100 mg/day, 200 mg/day, 400 mg/day, or 800 mg/day, or a matching placebo.

24 hours of blood samples will be drawn for pharmacokinetic analysis. Side effects will be assessed for the full 5 days.

Inclusion Criteria:

• Healthy men and women
• Ages 18 - 50 years
• BMI between 18.5 and 30
• Ability to read and speak English
• Education of 12 or more years or equivalent (at least GED received)

Exclusion Criteria:

• Medication changes in the past 30 days
• History of psychotropic medication therapy in the past 30 days
• Current or past 30 days opioid therapy
• Current or past 30 days erectile dysfunction therapy
• Significant medical conditions
• Hypertensive blood pressure, defined as either systolic pressure > 140 or diastolic pressure > 90
• Baseline heart rate > 100 bpm or < 50 bpm
• History of major psychiatric illness
• History of drug/alcohol abuse or current tobacco use
• Vulnerable populations including pregnant or nursing women, the incarcerated, or individuals with severe cognitive disorders
• History of allergic reaction or contraindication to icariin
• Baseline QIDS score > 7, current suicidal ideation, or history of suicide attempt
• Education history that includes Special Education or history of mental disability
• Clinically significant abnormalities on baseline labs and ECG results
• Current participation in any other pharmacotherapy studies