As far as I recall, Nettle Root Extract (Urtica dioica) is required to check the the proliferation of prostate cells in response to estrogen and sex hormone binding globulin. This is important in managing the estrogen:testosterone ratio. Nettle Root works synergistically with Pygeum, a compound with similar qualities like Nettle. However, hair loss itself is the result of complex biochemical processes involving, amongst others, the increased conversion of testosterone to dihydrotestosterone (DHT). Saw Palmetto (Serenoa repens), an alpha-adrenergic receptor inhibitor, as well as Phytosterols (most importantly, free Beta-Bitosterol) are very helpful in the mangament of the conversion of testosterone to DHT. Another potent substance for the management of hair-loss issues is Super-Oxide Dismutase (SOD).
As an aside, Superoxide Dismutase is, in many ways, the body's master antioxidant, with the key responsibility for neutralizing the most dangerous free radicals of all. These are the highly reactive superoxide radicals. These superoxide radicals, or anions (meaning negatively charged atoms), are generated when oxygen gains an excess electron. This occurs through the normal processes of metabolism.
If you are worried about the possibility of hair loss, just like most of us, it might help to take a combination of good-quality Nettle Root Extract, Pygeum, Saw Palmetto, Phytosterols (especially Beta-Sitosterol), and bioavailable Super-Oxide Dismutase.