No. Women who are treated with testosterone implants alone (no estrogen therapy) do not require progestin therapy. However, if estradiol, or other estrogen therapy is prescribed, progestins are also needed. The main indication for the use of synthetic progestins, like Provera® or progesterone, is to prevent the proliferation (stimulation) of the uterine lining caused by estrogen. Progestin therapy is NOT required if estrogen therapy is not prescribed. However, there may be other health benefits from the hormone, progesterone.
It may help with anxiety or insomnia. Interestingly, progesterone implants have been used since the 1940’s.