Popular in cuisines from Armenia to India for its flavor, fenugreek also has a long history of medicinal use. Most commonly in the West it is used to help new mothers produce milk, and it is indeed very useful for that.
Something you need to understand about testosterone (T) is that it’s not all usable at any given time, much of it being bound to a globulin that tamps it down. The rest is referred to as free for bioavailable testosterone and can be used for all its many functions. Obviously, it being in the title, the function at hand is sex drive. Higher free T = more libido.
This is an important distinction because while fenugreek does not increase T levels overall, it does increase the usable amount. This could explain why it is able to help weightlifters move more weight, which is normally caused by anti-oestrogenic effects, and at the same time help lactation or even firm up non-lactating breasts.
The amount to take, by the way, looks to be 500mg/day, making it a very inexpensive supplement as well as a fully natural one. Its slight bump up in sex drive makes it qualify as an aphrodisiac, if a mild one, with very good (and similarly mild) side effects.