All current commercially available testosterone preparations are produced from plant materials. In this regard, it could be said all testosterone products are natural.
There are herbal products, alternative preparations and androgen supplements which are marketed as mimicking the action of testosterone. These herbal products include Tribulus Terrestris, Ginseng, Sarsparilla, Damiana and Yohimbe 1111.
Alternative preparations such as DHEA (dehydroepiandrosterone) and androstenedione are prohibited in Australia and illegal purchases over the internet are regularly seized by the Australian Customs Service. They are also very weak androgens and are not suitable for androgen deficiency treatment. Androgen supplements also risk liver damage.
If you plan to use herbal or alternative preparations for your masculinisation, you should investigate if the preparations have ever been used in clinical trials. Checking up on the documented evidence of alternative preparations is in the interests of your own health. All clinical tests are reported in reputable scientific journals. Medical treatments are evaluated by other researchers and available for scrutiny in peer-reviewed scientific journals. The results of medical tests can always be verified and replicated.
There are no known herbal products that can replace the role of testosterone in the body to virilise the human body to the comparable testosterone levels of the adult male.
In short, herbal preparations will cost you more, but have a negligible effect. There is increasing concern that certain herbal preparations result in toxicity or are harmful in some way. The only safe, effective way to masculinise your body to that of an adult male is to use medical testosterone under the care of a qualified healthcare provider.