Progesterone or Progestogen?
The Difference Your Prescription May Be Hiding
By Dr Hazel Batten, Integrative GP at Remede Wellness Medicine
Almost every week in clinic, a patient tells me she is “on progesterone.” When we go through her medications together, what she is actually taking is drospirenone, levonorgestrel, or dienogest. These are not progesterone. They are progestogens, a related but distinct group of compounds, and the difference matters more than most patients (and many prescribers) realise.
Progesterone Is a Hormone Your Body Already Makes
Progesterone is the hormone produced by your ovaries after ovulation and, in smaller amounts, by your adrenal glands. When we prescribe it as micronised progesterone (the form used in body identical MHT), it is structurally identical to the hormone your own body produces. Your body cannot tell the difference between the progesterone made in your ovaries and the progesterone in a properly formulated capsule.
This matters clinically. Progesterone binds cleanly to the progesterone receptor. It has a calming, sleep supportive effect through its interaction with GABA receptors in the brain, which is part of why many women prescribed micronised progesterone notice improved sleep within days. It also has a well established safety profile when used as part of body identical MHT, particularly regarding breast tissue, which is one of the most common questions I am asked in consultation.
Progestogens Are a Different Category Entirely
Progestogen is the umbrella term for any compound, natural or synthetic, that acts on the progesterone receptor. Progesterone itself is technically a progestogen. But the synthetic compounds commonly prescribed under this umbrella, including drospirenone, levonorgestrel, and dienogest, are structurally different molecules built to mimic some, but not all, of progesterone’s actions.
Here is what patients are often taking without realising it is not progesterone:
Drospirenone
Found in many combined oral contraceptive pills and some MHT preparations. It has anti mineralocorticoid and anti androgenic properties, meaning it behaves differently in the body to natural progesterone, particularly around fluid balance and androgen pathways.
Levonorgestrel
Found in many oral contraceptive pills and in the hormonal IUD. It has androgenic activity, which can contribute to side effects such as mood changes, acne, or breast tenderness in sensitive individuals. It does not carry the same neurosteroid, sleep supportive activity as micronised progesterone.
Dienogest
Used primarily in endometriosis management for its strong progestational effect on endometrial tissue. It is effective for its intended purpose but is not interchangeable with progesterone when the goal is systemic hormone balance or MHT.
Why This Distinction Changes Clinical Decisions
When a patient says she has tried “progesterone” and it made her mood worse, or she stopped it because of bloating or low libido, closer questioning often reveals she was taking a synthetic progestogen, not progesterone itself. The symptom she experienced may be a known effect of that specific progestogen’s receptor activity, not a reflection of how she would respond to true progesterone.
This is not a criticism of progestogens. They have important, evidence based roles in contraception, endometriosis management, and endometrial protection. The issue is precision. When a patient and her doctor are not using the same vocabulary, treatment decisions get made on incomplete information. A woman who was told progesterone is not for her may never be offered a trial of the one hormone most likely to help her sleep, mood, and cycle symptoms, because the word progesterone was already used up on something else.
What I Ask My Patients to Check
If you are unsure what you are taking, the active ingredient on your medication box or PBS information leaflet will tell you. Look for the specific molecule name, not the brand name or the general category. If it says progesterone or micronised progesterone, that is the body identical hormone. If it lists any other name ending in “gestrel,” “gestrone,” or “gestimate” such as levonorgestrel, drospirenone, or dienogest, you are taking a progestogen, which is a different compound with a different action profile.
The Takeaway
Progesterone and progestogens both have a place in women’s health care. But they are not interchangeable, and the language we use to describe them should reflect that. If you have been told progesterone caused a side effect, it is worth checking exactly which molecule you were prescribed before ruling it out altogether. Understanding the difference is a simple step that can open up treatment options that may have been dismissed too early.
*This information is general in nature and does not replace individual medical advice. Please discuss your specific hormone therapy options with your treating doctor.*