As torrential noted, it is a marketing ploy to get you to pay thousands of dollars for an inferior TRT method (pellets).

As Gene noted, all testosterone products are "synthesized" making then "synthetic" in that nature...but the "bio-identical" term really originated to describe the CHEMICAL STRUCTURE of the hormones. Once again, as torrential astutely noted, this is only really a relevant term in FEMALE HRT where there are hormones used that are CHEMICALLY DIFFERENT than the body's own hormones (Premarin, prempro, etc, etc). For males, every major commercially available testosterone product is "bio-identical" in the sense that the actual TESTOSTERONE itself is identical to your body's own testosterone. For example, testosterone cypionate is simply testosterone (bio-identical) with an ester (cypionate) attached to control the timed release of the testosterone in the body. Once the ester (cypionate) is cleaved off, the testosterone released is BIO-IDENTICAL in structure to the body's testosterone.