Participants will be screened using the Aging Male Symptoms (AMS) Scale and the Androgen Deficiency in the Aging Male (ADAM) questionnaire to select candidates likely to have sub-optimal testosterone levels. Those meeting inclusion criteria will have total testosterone tested, and participants with baseline total testosterone of 500 ng/dL or less will be stratified and randomly assigned to one of three groups in a 1:1:1 ratio: Qualia Testosterone+ Formula 1, Qualia Testosterone+ Formula 2, or matched placebo.
Each participant will take 3 capsules of the assigned product once daily in the morning for 28 consecutive days. The placebo consists of vegetable/cellulose capsules containing inert rice powder, matched to the active capsules in appearance.
Blood samples for total and free testosterone (equilibrium dialysis) will be collected at baseline and day 26-28 at Ulta-affiliated phlebotomy sites, with morning collection recommended. Symptom questionnaires (AMS Scale, PROMIS Fatigue 10a, Safety and Tolerability survey) will be completed electronically at baseline, day 14, and day 28. A follow-up questionnaire will be completed at day 32-34. Regular check-in surveys will assess adherence and safety on days 1, 3, 7, 14, 21, and 28.
Statistical analyses will include paired t-tests or linear mixed-effects models for within-group differences, and linear mixed-effects models with fixed effects for group, time, and their interaction for between-group comparisons. The sample size was estimated to yield 80% power to detect an effect size of Cohen's d = 0.80 with a two-tailed t-test at a 0.05 significance level.