Bioidentical Oral Progesterone vs. Wild Yam Progesterone Creams

jaymedia7482321
Mar 20
5 min read

As a physician specializing in Natural Family Planning (NFP) and NaPro Technology, I work with women every day who are struggling with irregular cycles, unexplained infertility, recurrent miscarriages, and hormone imbalances. Many of them come to me after years of frustration—being told by their doctors that their only option is hormonal birth control or that their cycles are "just irregular" with no real solution. The truth? Your hormones matter, and they deserve real medical support. One of the most common hormone imbalances I see in my practice is low progesterone, a key hormone needed for a healthy cycle, implantation, and pregnancy. Many women ask me about natural progesterone options—especially the difference between Prometrium (oral progesterone) and over-the-counter topical progesterone creams. So today, I’m diving into the science behind bioidentical progesterone, and over-the-counter (OTC) wild yam progesterone creams. Continue reading to find out the difference in effectiveness, absorption, and chemical make up of each.

Understanding Progesterone in Fertility Awareness & NaPro Technology

If you track your cycle using fertility awareness methods (FAMs) or Natural Family Planning (NFP), you’ve probably noticed that progesterone plays a central role in the luteal phase (post-ovulation phase). It is primarily produced by the corpus luteum after ovulation and plays a critical role in maintaining the uterine lining, regulating cycle length, and sustaining pregnancy. Beyond reproduction, progesterone also balances estrogen, helps regulate mood, promotes relaxation, and even contributes to bone health.

In NaPro Technology (Natural Procreative Technology), we look closely at progesterone levels using cycle charting and targeted hormone testing—something conventional medicine often overlooks. When progesterone levels are low, women may experience short luteal phases (less than 11 days between ovulation and the start of your next period), 3 or more days of spotting before menstruation, increased risk of miscarriage, irregular cycles, anxiety, poor sleep, PMS symptoms, and symptoms of estrogen dominance such as bloating, breast tenderness, and heavy periods.

Women tracking their cycles using Natural Family Planning (NFP) or Fertility Awareness Methods (FAMs) can often identify patterns that suggest low progesterone, such as early or erratic temperature shifts and inadequate luteal phases. If you’ve been tracking your cycle and suspect a progesterone deficiency, you may be wondering, "Should I use natural progesterone cream or a prescription progesterone like Prometrium?" Let’s break it down with real science.

Where Do Prometrium and Wild Yam Progesterone Cream Come From?

Both Prometrium and progesterone creams originate from plant sources, but they undergo very different processing methods before they can be used by the human body. Prometrium is derived from wild yams or soybeans and is synthesized in a lab to create bioidentical progesterone, which is structurally identical to the progesterone naturally produced by a woman’s body. This allows it to be effectively recognized and utilized when taken as an oral micronized capsule.

Wild yam progesterone cream, on the other hand, is extracted from Dioscorea villosa, a type of wild yam. These yams contain diosgenin, a plant-based steroid precursor. However, the human body lacks the enzymes necessary to convert diosgenin into active progesterone on its own. The conversion requires a laboratory process, meaning that unless the cream has been specifically formulated to contain bioidentical progesterone, it is unlikely to have any meaningful hormonal effect.

Despite being marketed as a natural alternative, many over-the-counter creams contain only unprocessed wild yam extract, which has no proven hormonal activity in the human body. This distinction is important when evaluating which form of progesterone is actually effective for hormone support.

Product	Source	Processing Method	Final Form
Prometrium	Derived from wild yams or soybeans	Synthesized into bioidentical progesterone through lab conversion	Micronized oral capsule
Wild Yam Progesterone Cream	Extracted from Dioscorea villosa (wild yam)	Often not converted into active progesterone	Over-the-counter topical cream

Prometrium vs. Progesterone Cream Effectiveness: What Works?

Many women are drawn to progesterone creams because they are marketed as "natural alternatives" to prescription progesterone. However, scientific studies tell a different story. There is a big difference between what actually gets absorbed into your body and what’s just marketing hype. Prometrium is FDA-approved for luteal phase support, recurrent miscarriage, and menopause therapy. It is well-absorbed and has been clinically proven to raise serum progesterone levels. Additionally, it helps protect the endometrium when used alongside estrogen therapy in hormone replacement therapy (HRT), preventing the risk of hyperplasia and uterine cancer. Another benefit of oral progesterone is that its metabolites, such as allopregnanolone, contribute to improved sleep and reduced anxiety.

Wild yam progesterone cream, by contrast, has not been shown to effectively raise serum progesterone levels. Absorption through the skin is highly variable and often inadequate to achieve the levels necessary for significant physiological effects. Studies found that transdermal progesterone did not effectively raise serum progesterone levels in postmenopausal women. Another study showed no significant improvement in menopausal symptoms compared to placebo. Because of this, progesterone creams should not be relied upon for endometrial protection or fertility support.

One of the biggest risks associated with relying on progesterone cream is that it may provide a false sense of security to women who need higher doses of progesterone. If a woman is taking estrogen therapy without adequate progesterone, she is at risk for endometrial hyperplasia, which can lead to uterine cancer. No major medical organization recommends using over-the-counter progesterone creams as a substitute for medically prescribed progesterone.

Bioavailability & Absorption: How Well Does It Get Into the Bloodstream?

The way a medication is absorbed and utilized by the body—its bioavailability—is crucial when considering effectiveness. Prometrium, when taken orally, is absorbed through the digestive tract and metabolized by the liver. This allows for predictable dosing with known blood levels. One effect of liver metabolism is the production of sedative metabolites, which can help with sleep but may also cause drowsiness in some women.

Progesterone creams, on the other hand, are absorbed through the skin and enter circulation more slowly. However, this absorption is inconsistent and varies by individual. Some progesterone may be stored in fat cells rather than immediately entering circulation, leading to unpredictable effects. This makes it difficult to know exactly how much progesterone is being absorbed, which is a major concern for women relying on it for fertility support, miscarriage prevention, or hormone therapy.

Because of these inconsistencies, oral micronized progesterone, such as Prometrium, is the preferred choice for fertility, miscarriage prevention, and endometrial protection.

Key Takeaways: Which One is Better?

Factor	Prometrium (Oral Progesterone)	OTC Progesterone Cream
Effectiveness	Clinically proven for fertility, miscarriage prevention, and menopause	No strong evidence for efficacy in fertility or HRT
Absorption	Well-absorbed with predictable blood levels	Inconsistent absorption; unpredictable hormone delivery
FDA Approved?	Yes, regulated and prescribed	No, often sold as a cosmetic
Best Use Cases	Fertility, luteal phase support, endometrial protection	Possibly mild PMS relief but not recommended for serious hormonal support

Bottom Line: If you need progesterone for fertility, miscarriage prevention, or hormone balance, Prometrium is the clear winner. OTC progesterone creams are not a reliable replacement for medically prescribed bioidentical progesterone.

If you take one thing away from this post, let it be this: your cycle is a sign of your overall health. If you’re struggling with irregular cycles, infertility, or miscarriage, don’t ignore it.

You deserve answers and a healthcare provider who listens to your concerns.

Therefore, start tracking your cycles (if you don’t already), find a NaPro physician to help diagnose and treat the cause of any reproductive health issues, get hormone testing to check progesterone levels, and consider bioidentical progesterone (Prometrium) if needed.

Click here to find a list of NaPro and NFP-only physicians near you.

For more information on ways to naturally increase progesterone levels, I would recommend reading Real Food for Fertility. Also, taking certain supplements such as Magnesium and Vitamin E can help aid in progesterone production.