Testofen is a brand name for a fenugreek seed extract. The page uses it as one of its key ingredients.
Fenugreek is a seed used as a spice and in traditional herbal medicine. A branded extract indicates a defined preparation, which is more specific than plain fenugreek. The page does not state the amount per gummy or a standardization figure for it.
It describes the ingredient as having clinical research behind testosterone support, which we cover in another post.
Fenugreek is a legume, so people allergic to peanuts or chickpeas should be careful. It is also discussed for effects on blood sugar and can interact with some medicines, including blood thinners. Ask a doctor or pharmacist if that applies to you.