L-Arginine
Klotz et al. (1999): randomized placebo-controlled crossover trial in 32 men with mixed-type erectile dysfunction; 30 completed. Oral L-arginine 500 mg three times daily (1,500 mg/day) and placebo were each taken for 17 days, separated by a seven-day washout. KEED questionnaire scores did not differ significantly between treatments. Funding and conflict disclosures are not provided in the abstract.
Chen et al. (1999): randomized, double-blind placebo-controlled trial in 50 men with organic erectile dysfunction. After a two-week placebo run-in, treatment was 5 g/day for six weeks. The abstract reports subjective improvement in 9/29 treated men and 2/17 controls; objective measures, including penile hemodynamics, were unchanged. Instruments included O’Leary’s questionnaire, a sexual-function questionnaire, an activity diary and nitric-oxide metabolites. The abstract does not explain attrition, dosing frequency or funding.
Menafra et al. (2022): multicenter randomized, double-blind trial. 100 enrolled; 98 randomized (51/47); 95 completed (50/45). Bioarginina supplied 2 g three times daily, totaling 6 g/day for three months. Median IIEF-6 scores changed from 20 to 24 with L-arginine and remained 20 with placebo; Doppler blood-flow improvement was confined to the mild/moderate vascular subgroup. No study funding was reported; one author disclosed Damor consultancy outside this work.
Testostemem provides 300 mg per serving. These trials studied different amounts and clinical populations; they do not establish the same outcomes at 300 mg.
Maca
Gonzales et al. (2002): 12-week randomized, double-blind placebo-controlled trial in 57 healthy men aged 21–56. Gelatinized maca: 1,500 mg/day (30 men), 3,000 mg/day (15 men) or placebo (12 men). The doses comprised three or six 500 mg tablets daily. Measures included self-rated sexual desire, Hamilton depression and anxiety scales, and serum hormones. The paper does not provide a participant-flow or attrition account.
Reported desire improvement occurred in 40.0% of maca-treated men versus 0% of controls at eight weeks (p < 0.008), and 42.2% versus 0% at twelve weeks (p < 0.006). Testosterone did not differ between groups. Laboratorios Hersil supplied tablets and supported the study with Universidad Peruana Cayetano Heredia; no separate conflict statement was provided. Testostemem contains 150 mg of maca root extract per serving, a different preparation and amount.
Panax Ginseng
Reay et al. (2005): double-blind, placebo-controlled, balanced crossover study in 30 healthy young adults. Single doses of G115 extract (200 or 400 mg) were compared with placebo. Starting 60 minutes after dosing, participants repeated a ten-minute battery six times: Serial Threes, Serial Sevens, Rapid Visual Information Processing and a mental-fatigue rating. The 200 mg condition improved Serial Sevens performance and fatigue ratings at most time points. The accessible abstract does not report attrition or funding details.
Testostemem provides 100 mg of Panax ginseng root extract per serving. The trial describes G115 at its tested doses, rather than this preparation or amount.
Shatavari
Anders et al. (2020): eight-week randomized placebo-controlled trial; 18 recreationally trained men (10 active, eight placebo), all completing training. The 26 total volunteers included an overlapping reliability sample. Two matching 250 mg capsules daily supplied 500 mg Asparagus racemosus or cellulose. Blinding was not specified. Bench-press training occurred three times weekly.
Bench-press 1RM increased 14.3% versus 7.8% (p = 0.048), although adjusted post-training 1RM did not differ (p = 0.196). Adjusted repetitions at 70% of initial 1RM were 17.5 versus 15.2 (p = 0.044); percentage-change comparison was nonsignificant (p = 0.058). Testosterone and memory were not tested. Natreon funded the study and supplied products; authors declared no conflicts and no sponsor role in study conduct or publication.
Testostemem provides 50 mg per serving. The report does not establish an extract match to the 500 mg study material. The earlier Thakur et al. (2009) work examined botanical extracts in male rats and remains a separate animal-research reference.
