Bi-Est Creams vs Oral HRT: A Women's Hormone Therapy Guide
Creams, troches and capsules deliver hormones by different routes, and route genuinely changes how a hormone reaches your bloodstream. It does not, by itself, make one option better than another. Here is what separates them, and where a compounded preparation fits.
Compounded Bi-Est preparations are made individually to a prescriber's specified ratio and strength in the non sterile lab at Mixwell Compounding Pharmacy in Chino, CA.
What Bi-Est actually is
Bi-Est is a compounded combination of two estrogens, estradiol and estriol, prepared in a ratio the prescriber selects. No manufacturer makes this combination, so it is prepared individually by a compounding pharmacy under a valid prescription.
Estriol usually makes up the larger share of the formulation by weight. Estradiol accounts for most of the estrogenic activity. The two ratios you will hear most often are 80:20 and 50:50, written as estriol to estradiol.
Neither ratio is a default. It is a clinical choice the prescriber makes for the individual patient.
Where progesterone fits in
Progesterone is frequently prescribed alongside estrogen, and micronized progesterone is available as an FDA approved oral product. Compounding becomes relevant when the strength, route or combination is something manufactured products do not offer.
Compounded progesterone can be prepared as capsules, creams, troches or vaginal preparations, depending on what the prescriber specifies.
The first pass effect, explained simply
When you swallow a capsule, it is absorbed through your gut and travels to your liver before reaching the rest of your body. Your liver processes a portion of it on the way through. That is the first pass effect, and it happens with many oral medications.
When a hormone is absorbed through your skin or through the lining of your mouth, it enters your bloodstream directly. It reaches your liver later, along with everything else in general circulation, rather than in one concentrated pass.
Estrogens are fat soluble, which is a large part of why they absorb reasonably well through skin. That is chemistry, not marketing.
The difference in route is real pharmacology. What it means clinically for any individual patient is a judgment call for the prescriber, based on that person's history, symptoms and goals.
Comparing the routes
Compounded hormone preparations are available as transdermal creams, troches, oral capsules and vaginal preparations. FDA approved products exist for most of these routes, which is the column most comparisons leave out.
| Route | How it enters | Passes liver first | FDA approved products exist |
|---|---|---|---|
| Transdermal cream or gel | Absorbed through the skin into circulation | No | Yes. Approved estradiol patches, gels and sprays are available. |
| Troche or sublingual | Dissolves in the mouth, absorbed through the oral lining | Largely bypassed | Limited. Most troche formulations are compounded. |
| Oral capsule | Absorbed through the gut | Yes | Yes. Approved oral estradiol and micronized progesterone are available. |
| Vaginal cream or suppository | Absorbed through vaginal tissue, often for localized use | Largely bypassed | Yes, for several approved products. |
Transdermal delivery is not the same thing as compounded. An FDA approved transdermal estrogen is available. What compounding adds is the ability to specify a combination, ratio or strength that no manufacturer makes.
What bioidentical really means
Bioidentical means the hormone molecule is structurally identical to the one your body produces. Estradiol is estradiol whether it comes from a compounding pharmacy or a manufactured product.
Several FDA approved hormone products are bioidentical. Estradiol patches and gels, and micronized progesterone capsules, all contain bioidentical hormones and went through the FDA approval process.
Bioidentical is a description of the molecule. It is not, by itself, a claim about safety or effectiveness, and the National Academies specifically cautioned against treating it as one.
Where personalized dosing comes in
Compounding lets a prescriber specify a strength, combination or route that manufactured products do not offer. That is the practical value, and it is narrower and more useful than the way it is often marketed.
What compounding can do
- Prepare a strength between or below manufactured options
- Combine estradiol, estriol, progesterone, testosterone or DHEA in one preparation
- Leave out a dye, preservative or filler a patient reacts to
- Provide a route that suits the patient when a capsule does not
What it does not mean
- That a compounded preparation is safer than an approved product
- That it is more effective than an approved product
- That it is tested the way an approved product is tested
- That it suits every patient better than a commercial option
Not sure whether a compounded preparation is the right fit for your patient? Talk it through with a compounding pharmacist first.
Call (909) 378-7301The bases behind the cream
For a transdermal preparation, the base is the vehicle carrying the hormone, and it affects how actives move through skin and how stable the preparation stays. Mixwell is a PCCA member pharmacy and selects the base to match the route on the prescription.
| Base | Route | What it provides |
|---|---|---|
| Lipoderm | Transdermal | PCCA's flagship permeation enhancing transdermal base, widely used for carrying actives through skin, with a smooth finish. |
| PermE8 | Transdermal, anhydrous | An anhydrous permeation enhancing gel with water activity below 0.6, supporting extended default beyond use dates and multiple actives. |
| MucoLox | Vaginal and mucosal | A mucoadhesive base designed to adhere to mucosal tissue, used for localized vaginal preparations when prescribed. |
What the evidence says
The National Academies concluded in 2020 that evidence supporting the safety and effectiveness of compounded bioidentical hormone therapy is limited. The report recommended restricting use to patients who cannot use an FDA approved product, such as those with a documented allergy to an ingredient or who need a dosage form that is not commercially available.
On formulation science, a 2025 study in Pharmaceutics examined compounded estradiol and Bi-Est preparations in permeation enhancing bases and compared them with a commercial estradiol transdermal gel, looking at how base selection affects transdermal estrogen delivery.
The National Academies summary is a fair one, and it describes exactly the situations where a prescriber sends a compounded hormone prescription to this pharmacy.
Sending a prescription to Mixwell
Note the hormones, strengths, ratio, route and base preference on a patient specific prescription, then fax or e prescribe it to the Chino pharmacy. Writing pharmacist's choice for the base is fine, and the pharmacy will match it to the route.
- Specify the hormones, strengths, ratio, route and base preference, or write pharmacist's choice.
- Fax or e prescribe to Mixwell Compounding Pharmacy in Chino, CA.
- Call (909) 378-7301 to confirm the formulation or check current turnaround time.
- The patient can pick up in Chino, or the pharmacy can deliver.
Bi-Est cream, estriol to estradiol 80:20, total strength as specified, in Lipoderm or pharmacist's choice. Dispense 60 mL in an airless pump. Apply as directed.
- Pharmacy:
- Mixwell Compounding Pharmacy
- Address:
- 13788 Roswell Ave, Ste 158, Chino, CA 91710
- Phone:
- (909) 378-7301
- Fax:
- (909) 378-7071
- Email:
- info@mixwellpharmacy.com
The wording above is a formatting example only. All clinical parameters are determined by the prescriber.
Serving prescribers and patients in California
Mixwell Compounding Pharmacy is located in Chino, CA and works with women's health prescribers across the Inland Empire, Los Angeles County and Orange County. Patients can collect their preparation at the Chino pharmacy, and delivery is available across California.
- Chino
- Chino Hills
- Ontario
- Rancho Cucamonga
- Upland
- Pomona
- Diamond Bar
- Corona
- Riverside
- Eastvale
- Brea
- Fullerton
Common questions
Is a Bi-Est cream better than oral HRT?
Neither route is universally better. Transdermal delivery avoids the first pass through the liver that oral capsules go through, which is a real pharmacologic difference, but what that means for any individual is a clinical decision. FDA approved oral and FDA approved transdermal options both exist, and the prescriber weighs the patient's history and goals.
Are bioidentical hormones the same as compounded hormones?
No. Bioidentical describes a molecule that is structurally identical to what the body produces, and several FDA approved products contain bioidentical hormones. Compounded means the preparation was made individually by a pharmacy for one patient under a prescription.
What ratios of Bi-Est can be compounded?
Mixwell compounds to whatever ratio and total strength the prescription specifies. Common prescriber choices include 80:20 and 50:50 estriol to estradiol, but the ratio is the prescriber's decision.
Can progesterone be included in the same preparation?
Yes. Progesterone, testosterone and DHEA can be compounded alongside Bi-Est in a single preparation when the prescriber specifies it.
Why would a prescriber choose compounded over an approved product?
Usually because something specific does not fit, such as a reaction to an ingredient in a commercial product, a strength that is not manufactured, or a dosage form that is not commercially available. The National Academies recommended reserving compounded hormone therapy for situations like these.
Should I talk to my provider before starting hormone therapy?
Yes. FDA recommends that patients talk with their health care professional about their specific circumstances before taking any medication, including compounded preparations.
Does Mixwell accept insurance?
Mixwell does not accept insurance. Call (909) 378-7301 to discuss current pricing.
Key Takeaways
- Bi-Est is a compounded combination of estradiol and estriol prepared in a ratio the prescriber selects, and no manufacturer makes it.
- Transdermal creams and troches largely bypass the first pass through the liver, while oral capsules do not, which is a difference in route rather than a claim of superiority.
- FDA approved transdermal and bioidentical hormone products already exist, so compounding fills specific gaps rather than replacing approved therapy.
- The National Academies recommended reserving compounded bioidentical hormone therapy for patients who cannot use an FDA approved product.
- Compounded hormone preparations are not FDA approved and require a valid prescription from a licensed prescriber.
Sources
- National Academies of Sciences, Engineering, and Medicine. The Clinical Utility of Compounded Bioidentical Hormone Therapy: A Review of Safety, Effectiveness, and Use. Washington, DC: The National Academies Press; 2020. doi:10.17226/25791
- In Vitro Percutaneous Absorption of Permeation Enhancing Estrogen Formulations. Pharmaceutics. 2025. PMC12030386
- Files JA, Ko MG, Pruthi S. Bioidentical hormone therapy. Mayo Clinic Proceedings. 2011;86(7):673-680. PMC3127562
- U.S. Food and Drug Administration. Compounding and the FD&C Act, Section 503A. FDA Human Drug Compounding.
- Lipoderm, PermE8 and MucoLox are compounding bases from Professional Compounding Centers of America. Base characteristics per manufacturer technical documentation.