Bioidentical and Compounded Hormones: A Clear Guide Through the Confusion

What 'Bioidentical' Actually Means (and What It Doesn't)

The word bioidentical is everywhere in perimenopause and menopause conversations, and it's one of the most frequently misunderstood terms in this space. Bioidentical simply means that the hormone molecule is chemically identical in structure to the hormone your body produces naturally. It says nothing about where the hormone comes from, how it's made, whether it's FDA-approved, or how safe it is. It is a description of molecular structure, not a quality designation or a safety stamp.

Here's the important thing many people don't realize: many FDA-approved hormone products are bioidentical. Estradiol patches like Vivelle-Dot and Climara, estradiol gels like Estrogel and Divigel, and oral micronized progesterone sold as Prometrium are all bioidentical by this definition. They are made from plant-derived precursors, typically yam or soy, and processed into molecules that are structurally identical to human estradiol and progesterone. These products are manufactured under rigorous FDA quality controls and have been tested in clinical trials.

The term bioidentical has been heavily marketed by the compounding pharmacy industry in a way that implies all bioidentical products are superior to conventional HRT. That marketing conflates two separate things: the molecular structure of the hormone and the regulatory oversight of the product. You can have bioidentical hormones that are FDA-approved and extensively tested, or bioidentical hormones that are compounded in a pharmacy and have no clinical trial data behind them. The term alone tells you which you're dealing with.

FDA-Approved Bioidentical Options: What's Available

If you want bioidentical hormones with the backing of FDA oversight and clinical trial data, you have quite a few options. For estrogen, FDA-approved bioidentical products include transdermal patches in multiple doses, estradiol gels and sprays, and vaginal formulations. All of these use 17-beta estradiol, the same molecule your ovaries produced before perimenopause. Oral estradiol pills are also available and bioidentical, though, as discussed elsewhere, transdermal delivery is generally preferred to avoid liver first-pass effects.

For progesterone, micronized progesterone (Prometrium in the US) is an FDA-approved bioidentical progesterone capsule. It is the closest commercially available equivalent to the progesterone your body produces. It has a favorable safety profile compared to synthetic progestins and is the preferred progesterone for many menopause specialists. It is also available as a vaginal gel (Prochieve/Crinone), though that formulation is primarily used in fertility medicine.

For testosterone, there are no FDA-approved formulations for women in the United States, which creates a gap that compounding pharmacies often fill. FDA-approved testosterone products exist for men (patches, gels, injections) and are sometimes used off-label for women at much lower doses. This is a legitimate clinical gap, and it's one of the areas where compounding genuinely addresses an unmet need.

What Compounded Hormones Are and How They Differ

Compounded hormone preparations are custom-made by a compounding pharmacy, meaning they're mixed to order based on a prescriber's specifications. Compounding serves legitimate and important purposes in medicine: it allows doses not available in commercial products, combinations that don't exist in standard formulations, alternative delivery forms for patients who can't tolerate standard routes, and hormone types (like testosterone for women) that have no FDA-approved commercial alternative.

The critical distinction is regulatory oversight. FDA-approved commercial hormone products go through extensive clinical trials demonstrating safety and efficacy, and their manufacturing facilities are inspected and regulated by the FDA. Compounded preparations do not go through this process. Compounding pharmacies are regulated primarily by state pharmacy boards rather than the FDA, and the level of oversight varies significantly by state. The FDA does have some oversight of compounding pharmacies that compound in bulk, but individual compounding pharmacies preparing custom formulations operate under a different framework.

This doesn't mean compounded hormones are uniformly unsafe. Many compounding pharmacies operate to high standards and produce consistent, quality products. But it does mean there is inherently more variability. A compounded cream labeled as containing 100mg of progesterone may not contain exactly that amount, because the same rigorous testing that commercial manufacturers must perform is not required of compounders. Potency, purity, and sterility can all vary in ways that are not possible to verify from the product label alone.

Legitimate Uses for Compounded HRT

Given the regulatory concerns, when does compounding make sense? There are several situations where compounded hormones address real clinical needs that FDA-approved products don't cover. The most clear-cut case is testosterone for women. Since no FDA-approved testosterone preparation exists in appropriate doses for women, compounded testosterone creams or gels at low doses (typically 0.5 to 2mg daily) are the standard way to prescribe testosterone in menopause medicine. This is a well-established clinical practice, and the off-label use of low-dose compounded testosterone for women is widely supported by menopause specialists.

Another legitimate use is when a patient cannot tolerate standard commercial formulations due to ingredients like peanut oil (Prometrium contains peanut oil and is contraindicated for peanut allergies), or when a specific dose combination isn't available commercially. Some women do better with estrogen delivered in ways not commercially available, such as certain compounded vaginal preparations. Compounding can also be appropriate when a patient has a sensitivity to a preservative or inactive ingredient in a commercial product.

The key distinction is whether the choice of compounding is driven by a genuine clinical need or primarily by marketing claims. A prescription for a compounded product because a specific dose or delivery form isn't commercially available is clinically sound. A prescription for a compounded product because a provider's website claims their custom formulations are more natural or more precisely tailored than commercial options warrants more scrutiny.

The Pellet Therapy Controversy

Subcutaneous pellet therapy is a form of hormone delivery that involves implanting small pellets containing hormones under the skin, typically in the hip area, where they release hormones over 3 to 6 months. Pellet therapy has become increasingly popular in the direct-pay medical spa and functional medicine markets. It is almost always a compounded product, and it carries specific concerns that set it apart from other compounded hormone options.

The main concern with pellet therapy is that it provides non-adjustable, sustained hormone delivery. Once the pellet is implanted, you cannot reduce the dose if you experience side effects. The dose is set based on body weight and symptoms but lacks the flexibility of topical or oral formulations that can be stopped or adjusted quickly. Women on testosterone pellets sometimes experience supraphysiologic testosterone levels (levels well above the normal female range), with associated side effects including acne, hair thinning, and potentially permanent voice changes at very high doses.

Another concern is the financial model. Pellet therapy is typically cash-pay and not covered by insurance, and practices offering it often profit significantly from each implantation. This creates a financial incentive structure that doesn't necessarily align with conservative, individualized prescribing. It's not that pellet therapy is inherently dangerous for everyone, but the specific combination of non-adjustable dosing, potential for supraphysiologic levels, and the financial incentive model makes it an area where careful scrutiny is warranted. Most menopause specialist organizations prefer adjustable delivery methods, particularly for testosterone.

Saliva and Urine Testing in Compounding Practices

Compounding-focused practices, particularly in the functional medicine and integrative medicine space, often rely heavily on saliva and urine hormone testing to guide prescribing. These test types are not used in mainstream menopause medicine for good reasons. Saliva hormone levels do not reliably correlate with serum hormone levels or with tissue hormone activity. They vary with time of day, what you've eaten or drunk, and other factors that are difficult to control. Using saliva estradiol or progesterone levels to guide HRT dosing is not supported by the evidence base that regulates standard medical practice.

Urine hormone testing, particularly through services like DUTCH, measures hormone metabolites and can provide information about how your body is processing hormones. This data can be interesting and is not inherently useless, but using it to drive specific compounding prescriptions for complex hormone protocols is a step beyond what the evidence supports. The metabolite information from DUTCH testing is more useful as a general pattern assessment than as a precise guide for dosing.

If a practice is basing your compounded hormone prescription primarily on saliva or urine testing rather than on clinical symptom assessment and standard serum hormone levels, that's worth understanding. It doesn't necessarily mean the care is bad, but it does mean you're operating outside the evidence-based standard of care for hormone prescribing, and you should factor that into your evaluation of the approach.

How to Evaluate a Compounding Provider

If you decide that compounded hormones are appropriate for your situation, choosing a quality compounding pharmacy matters. Look for pharmacies that are PCAB-accredited (accredited by the Pharmacy Compounding Accreditation Board), which indicates they've voluntarily met quality standards that exceed the baseline state pharmacy board requirements. PCAB-accredited pharmacies are more likely to test their products for potency and consistency.

Also consider how the prescription is being written. A compounding prescription for a specific testosterone dose to supplement standard FDA-approved estrogen therapy, written by a menopause specialist who is monitoring your serum hormone levels and clinical response, is a very different situation from a compounding prescription for a complex multicompound cream intended to replace all standard HRT, written based on a saliva panel at a medical spa.

Your prescribing provider is as important as the pharmacy. A provider who is prescribing compounded hormones as a complement to standard menopause medicine practice, and who monitors your response with clinical assessment and serum levels, is practicing thoughtfully. A provider who is using compounded hormones as part of a boutique concierge model with minimal monitoring and strong financial incentives is worth approaching with more caution.

When you're evaluating a provider who uses compounded hormones, look at their monitoring practices as much as their prescribing habits. A provider who prescribes compounded testosterone but monitors your levels every 6 months and adjusts based on clinical response is practicing thoughtfully. A provider who prescribes a complex multicompound cream and then doesn't see you for a year is a different situation. The formulation matters, but the ongoing relationship and monitoring matter just as much.

Medical Disclaimer

This article is written for general informational purposes only and does not constitute medical advice. Decisions about hormone therapy formulations, including compounded preparations, should always be made in partnership with a qualified healthcare provider who knows your full medical history. The information here is not a substitute for a clinical evaluation. If you have questions about bioidentical or compounded hormones, please consult a licensed medical professional with expertise in menopause medicine.