Are bioidentical hormones natural or not? The answer depends on your outlook. They are manufactured, so if that makes them less than natural in your book they will not fit into the natural supplements for testosterone replacement category for you. However, unlike synthetic hormones, bioidentical hormones have the same molecular structure as hormones created by your body. They can be metabolized and side effects are minimal. Bioidentical hormones are found in topical creams designed to help balance your hormone levels. These creams include products like:
Other significant adverse effects of testosterone supplementation include acceleration of pre-existing prostate cancer growth in individuals who have undergone androgen deprivation; increased hematocrit , which can require venipuncture in order to treat; and, exacerbation of sleep apnea .  Adverse effects may also include minor side-effects such as acne and oily skin, as well as, significant hair loss and/or thinning of the hair, which may be prevented with 5-alpha reductase inhibitors ordinarily used for the treatment of benign prostatic hyperplasia , such as finasteride .  Exogenous testosterone may also cause suppression of spermatogenesis , leading to, in some cases, infertility.  It is recommended that physicians screen for prostate cancer with a digital rectal exam and prostate-specific antigen (PSA) level before starting therapy, and monitor PSA and hematocrit levels closely during therapy.