Progesterone is a naturally occurring steroid hormone that plays a major role in the menstrual cycle, pregnancy, and endocrine balance. When prescribed as a medication, it is often administered as “micronized progesterone.” This term refers to reducing the progesterone particles to an ultra-fine powder, typically suspended in oil. Micronization is necessary because standard progesterone is poorly absorbed when taken orally. By increasing the surface area, this technique greatly improves the absorption and bioavailability of the oral dose.
The Starting Precursor: Plant Sources
The journey of micronized progesterone begins with specific plant materials containing a steroid precursor. The primary raw material is a compound called diosgenin, a type of phytosterol. This precursor is found in the tubers of certain species of yams, most notably the Mexican wild yam, Dioscorea villosa. A secondary source of phytosterols is derived from soybeans.
It is important to understand that eating wild yams or consuming soybeans will not cause the body to produce more progesterone, as the plant compounds are chemically distinct and cannot be converted by human enzymes. These plant sterols must first be extracted and purified to become the starting point for a complex chemical process.
From Plant Compound to Progesterone: The Conversion Process
The transformation of the plant precursor, diosgenin, into progesterone requires a sophisticated multi-step laboratory technique known as semi-synthesis. This process is necessary because the chemical structure of diosgenin must be fundamentally altered to create a molecule identical to the hormone produced by human ovaries. The foundational method for this conversion is often referred to as the Marker degradation, named after chemist Russell Marker who pioneered the technique in the 1940s.
This degradation involves a series of reactions to cleave the side chain from the diosgenin molecule, which is a key step in creating the core structure of progesterone. The chemical steps include processes like oxidation, hydrolysis, and cyclization, which systematically modify the original plant structure, resulting in a final compound structurally identical to the natural human hormone.
Defining Bio-Identical Versus Natural
The terms used to describe hormone medications can be confusing, particularly the distinction between “bio-identical” and “natural.” Micronized progesterone is classified as “bio-identical” because its molecular structure is an exact match to the progesterone produced by the human body. This structural identity allows the hormone to interact seamlessly with the body’s receptors, mimicking natural function.
The term “natural” is often used in marketing to suggest the product is simply extracted from a plant, which is a misconception. While the starting material is plant-derived, the conversion into progesterone is a chemical manufacturing process, meaning the final product is a chemically synthesized compound, not a raw extract.
Bio-Identical vs. Synthetic Progestins
This distinction separates micronized progesterone from synthetic progestins, which are chemically modified versions of the hormone. Synthetic progestins possess an altered chemical structure, which can lead to different interactions or side effects in the body.