This paper studies transmutation theory as found in the texts attributed to Zosimus of Panopolis, "the philosopher Synesius," and "the philosopher Olympiodorus of Alexandria." It shows that transmutation theory (i.e. a theory explaining the complete transformation of substances) is mostly absent from the work attributed to these three authors. The text attributed to Synesius describes a gilding process, which is similar to those described by Pliny and Vitruvius. The commentary attributed to Olympiodorus is the only text studied here that describes something similar to a transmutation theory. It is unclear, however, if this was a theory of transmutation or if the writer meant something more like the literal meaning of the word "ekstrophē," a term used to describe the transformation of metals, as the "turning inside-out" of what is hidden in a substance. A similar conception of ekstrophē can be found in the works of Zosimus, who discussed transmutation to make an analogy with self-purification processes, which, from the perspective of his own anthropogony, consisted in the "turning inside-out" of the "inner human" (esō anthrōpos).