What is another name for progesterone? Understanding Progestin and Bioidentical Forms

October 9, 2025 •

3 min read

While many people use the terms interchangeably, progestin is the key another name for progesterone, but it refers specifically to the synthetic version of the hormone. It is crucial for patients considering hormone therapies to understand the distinction, as bioidentical progesterone and synthetic progestins have different chemical structures and effects on the body.

Quick Summary

Explores the key differences between the natural hormone progesterone and the synthetic version, progestin. Covers the chemical structure, medical uses, and notable examples of each, highlighting why this distinction is important for patients.

Key Points

Progestin is a Key Alternative Name: The term 'progestin' is used to refer to any synthetic substance that mimics the action of the natural hormone progesterone.
Progesterone vs. Progestin: The primary difference is chemical structure; progesterone is the natural or bioidentical form, while progestin is a lab-made version.
Brand Names for Bioidentical Progesterone: Examples of FDA-approved bioidentical progesterone include oral capsules like Prometrium and vaginal gels like Crinone.
Brand Names for Synthetic Progestins: Common progestin medications include Provera (medroxyprogesterone acetate) and those used in birth control like levonorgestrel.
Different Clinical Effects: Due to their different chemical structures, progestins can have different risk profiles and side effect potential compared to bioidentical progesterone, as highlighted in the Women's Health Initiative study.
Used in Hormone Therapy and Contraception: Progesterone is often used in bioidentical hormone replacement therapy (BHRT), while progestins are commonly found in oral contraceptives and hormonal IUDs.

Progesterone: The Natural Hormone

Progesterone is a naturally occurring steroid hormone produced primarily by the corpus luteum in the ovary following ovulation. It plays a critical role in the female menstrual cycle and in supporting early pregnancy. In pharmacology, progesterone can also refer to medications that are chemically and molecularly identical to the hormone produced by the body, often called 'bioidentical progesterone'. These bioidentical forms are manufactured in a lab, typically derived from plant chemicals like those found in wild yams, but are structurally identical to the body's own hormone.

Examples of Bioidentical Progesterone

Oral Capsules: Brand names like Prometrium offer micronized oral progesterone for systemic use.
Vaginal Inserts/Gels: Products such as Crinone and Endometrin are used for localized delivery, often for fertility treatment.
Injections: Progesterone in oil (PIO) can be administered via intramuscular injection for fertility support.

Progestin: The Synthetic Alternative

Another name for progesterone, progestin specifically designates a synthetic substance designed to mimic the effects of natural progesterone. The key difference lies in their chemical makeup; progestins have a different molecular structure, which can influence their potency, how they are metabolized, and their potential side effect profiles. The development of progestins allowed pharmaceutical companies to patent the unique compounds, leading to profitable and widely used medications.

How Progestins Differ from Progesterone

Chemical Structure: Unlike bioidentical progesterone, progestins are not identical to the body's hormone. This structural variation causes them to interact differently with hormone receptors in the body.
Potency: Some progestins are significantly more potent than natural progesterone, which can be advantageous for specific treatments but also increases the risk of certain side effects.
Side Effects: Clinical studies, including the Women's Health Initiative (WHI), have demonstrated that certain synthetic progestins are associated with a higher risk of side effects like cardiovascular issues and breast cancer compared to bioidentical progesterone.

Comparison Table: Progesterone vs. Progestin


Feature	Progesterone (Bioidentical)	Progestin (Synthetic)
Source	Produced naturally in the body; commercially derived from plants	Manufactured synthetically in a laboratory
Chemical Structure	Identical to the body's natural progesterone	Similar to, but not identical to, natural progesterone
Common Examples	Prometrium, Crinone, Endometrin	Provera (medroxyprogesterone acetate), norethindrone, levonorgestrel
Primary Uses	Hormone replacement therapy (HRT), fertility support, amenorrhea treatment	Hormonal contraception (birth control pills, IUDs), some HRT
Risk Profile	Studies suggest a potentially lower risk of certain side effects (e.g., breast cancer, cardiovascular) compared to some progestins	Associated with a higher risk of certain side effects in some studies, such as cardiovascular events and breast cancer
Patentability	Not patentable as it is a natural compound	Can be patented due to its unique chemical structure

The Importance of Terminology in Pharmacology

For both healthcare providers and patients, recognizing the precise terminology is vital. When discussing medications, using the correct term—progesterone for the bioidentical version and progestin for the synthetic—avoids confusion and ensures the right therapy is administered. For example, the risk profile of a patient receiving oral micronized progesterone (Prometrium) in a bioidentical HRT regimen is not the same as someone taking a progestin-based contraceptive.

Understanding the nuanced language is especially important when reviewing medical literature or research. For instance, an article reporting adverse effects from "progestins" might not apply to natural bioidentical progesterone, a distinction that has significant implications for treatment decisions and patient safety.

Conclusion: More Than Just a Name

In summary, while there are technical chemical names like corpus luteum hormone, the most common and important alternative name to understand is progestin, which refers to synthetic compounds. The core of the matter lies in the distinction between the natural, bioidentical progesterone and its synthetic mimicker, progestin. This knowledge empowers patients to engage more meaningfully with their healthcare providers about their treatment options, ensuring clarity on the medication's source, potential risks, and side effects. For those on hormone therapy, asking about the specific type of progesterone product being used—natural or synthetic—is a crucial step for informed decision-making.

Learn more about progestins and their uses.

Frequently Asked Questions

The generic name for the brand-name medication Prometrium is progesterone. It is a micronized oral progesterone product that is chemically identical to the natural hormone.

No, they are not the same. Progesterone is the natural, bioidentical hormone, while progestin is a synthetic, lab-made substance designed to have progesterone-like effects in the body but with a different chemical structure.

Yes, bioidentical progesterone is often derived from plant sources, such as wild yams. However, the conversion process to make it chemically identical to human progesterone requires laboratory synthesis.

The distinction is critical because their differing chemical structures can result in different pharmacological properties, including varying risk profiles for side effects such as breast cancer and cardiovascular events, and different effects on mood.

Examples of progestin-only birth control include the 'mini-pill' containing norethindrone (brands like Camila, Errin) and hormonal IUDs that release levonorgestrel (e.g., Mirena).

Yes, it is possible. Bioidentical progesterone is often noted for its calming effects on the brain, while some synthetic progestins have been associated with mood swings, depression, and anxiety in some women.

The safety profile is a subject of ongoing research. Some studies, including findings from the Women's Health Initiative, have suggested that certain synthetic progestins may carry higher risks of cardiovascular issues and breast cancer compared to bioidentical progesterone, though individual factors are also important.