Horny goat weed is first in the blend order, so it is the largest share of the 1,200 mg. It is also the ingredient with the most interesting negative finding on this page.
Its active compound is icariin. In 2019, Brown and colleagues published a randomised, double-blind, placebo-controlled human safety and pharmacokinetics trial in Natural Product Communications. They gave 24 healthy adults icariin at five dose levels: 100, 200, 400, 840 and 1,680 milligrams.
The finding was not about effect. It was about whether the compound gets into the blood at all. Blood levels were very low or undetectable, with essentially all plasma samples falling below the assay's 1 ng/mL detection threshold. The authors noted that this prevented any determination of pharmacokinetic properties.
In plain terms: at doses up to 1,680 mg of the isolated compound, they could not measure icariin in the bloodstream. Whatever quantity of horny goat weed extract is in this capsule, and it is the largest single share, the absorption question sits in front of the dose question.
It was reasonably well tolerated, which is its own useful finding. Two participants discontinued at the highest dose because of gastrointestinal distress.