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In recent years, the term “bioidentical hormones” has received attention in the world of health and wellness. With promises of safer hormone replacement therapy (HRT) and more natural treatment options for hormonal imbalances, bioidentical hormones have attracted support as well as criticism. But what exactly are bioidentical hormones, and what sets them apart from traditional hormone therapies? Let’s look at the concept of bioidentical hormones, exploring their origins, uses, benefits, and potential risks.
Bioidentical hormones are chemically identical to those naturally produced by the human body. The term “bioidentical” describes these hormones because they match the molecular structure of estrogen, progesterone, and testosterone. This similarity is a critical aspect of bioidentical hormone therapy, as it suggests that the body may more easily recognize and process these hormones.
Bioidentical sex hormones are primarily used in hormone replacement therapy (HRT), a treatment designed to address hormonal imbalances or deficiencies. HRT is commonly associated with menopause and perimenopause in women, where estrogen and progesterone levels fluctuate and decrease, leading to symptoms such as hot flashes, mood swings, and vaginal dryness. Similarly, testosterone replacement therapy is used in men to treat symptoms of low testosterone, such as decreased libido, fatigue, and muscle loss. It is also used at lower doses in women to help improve libido and energy.
Bioidentical sex hormones – estrogen, progesterone, and testosterone – are synthesized from plant sources, typically soybeans or wild yams. While these plants do not contain hormones, they contain precursors like diosgenin, which can be chemically converted into hormones identical to human ones. This synthesis is carried out in laboratories, ensuring that the final product matches the structure of human hormones.
Bioidentical hormones are available in two forms: manufactured and compounded. Manufactured medications come in brand names and, in some cases, generic forms. Prescriptions for manufactured medications can be filled at traditional pharmacies and are often covered by health insurance.
Compounded medications are only available by prescription from specialty compounding pharmacies, where they are custom-produced for each patient.
Bioidentical estrogen
Bioidentical estrogen comes in a variety of forms, including the following FDA-approved brands and generics:
- Oral: Estrace (17β-estradiol) and generic 17β-estradiol
- Patches: Alora, Climara, Esclim, Estraderm, Vivelle, Vivelle-Dot, Minivelle, and Menostar
- Cream: Estrasorb, Estrace, Estragyn
- Gel: EstroGel, Divigel, and Elestrin
- Spray: Evamist
- Vaginal insert: Estring, Femring, Imvexxy, Vagifem, and Yuvafem
Bioidentical progesterone
There is one form of FDA-approved bioidentical progesterone, the oral medication Prometrium, along with its generic (progesterone, USP).
Bioidentical progesterone is also available in an FDA-approved gel, Crinone, and an insert, Endometrin.
There’s also an FDA-approved combination oral estradiol/progesterone pill called Bijuvia.
Bioidentical testosterone
As discussed earlier, all the prescription testosterone medications on the market – including capsules, gels, patches, implants, and injections – are bioidentical. Some of the brands of testosterone include Androderm, AndroGel, Fortesta, and Testim, among others.
While all the various forms are typically prescribed for use in men, the typical form of testosterone given to women is transdermal, such as a gel, patch, or cream. These transdermal forms are preferred because they are easier to use and offer more flexibility in adjusting the dose.
Non-bioidentical hormones have the following key characteristics:
- Unlike bioidentical hormones, non-bioidentical hormones are not structurally identical to the hormones naturally produced by the human body,
- Non-identical hormones resemble natural human hormones but have slightly different molecular structures.
- Non-identical hormones are mass-produced in standard doses, whereas bioidentical hormones can be more easily customized to individual needs.
The most common non-bioidentical hormones are conjugated equine estrogens (CEE), derived from the urine of pregnant horses, and medroxyprogesterone acetate (MPA).
Non-bioidentical hormones are found in several heavily prescribed oral medications for menopause – Premarin, Prempro, and Premphase. Premarin includes CEE, and Prempro and Premphase treatment combines CEE with MPA. Other brand names of conjugated oral estrogen include Cenestin and Enjuvia. Premarin also comes as a vaginal cream.
The brand names of non-bioidentical progesterone (also known as progestins) include Provera (medroxyprogesterone acetate), Micronor (norethindrone), Aygestin (norethindrone acetate), and Camila, Errin, Heather, Incassia, Jencycla (norethindrone).
There are also non-bioidentical oral estrogen/progestin combination pills, including Activella, Lopreeza, Amabelz, Mimivey (estradiol/norethindrone acetate), Angeliq (estradiol/drospirenone), and FemHrt, Fyavolv, Jinteli (norethindrone acetate/ethinyl estradiol). Some patches combine bioidentical estrogen with non-bioidentical progesterone. These include ClimaraPro (estradiol/levonorgestrel) and Combipatch (estradiol/norethindrone acetate).
All the prescription testosterone medications on the market are considered bioidentical.
One of the chief criticisms of bioidentical hormones is based on a misunderstanding of the definition of bioidenticals. Currently, various brands of manufactured bioidentical hormones are FDA-approved. Before these drugs became available, however, these bioidentical hormones were already being prescribed, but prescriptions had to be custom-prepared by compounding pharmacies. Still, some medical professionals hear the term “bioidentical” and immediately assume it refers to compounded bioidenticals.
Compounded medications are a concern for some because they are not FDA-approved. In addition, because compounded prescriptions are individually formulated for each patient, it’s challenging to study them for effectiveness or safety. For this reason, various organizations, including the Endocrine Society, the American College of Obstetricians and Gynecologists (ACOG), and the North American Menopause Society (NAMS), have issued position statements cautioning against the routine use of compounded bioidentical hormone therapy, citing concerns about variable purity and potency, quality control issues, lack of efficacy and safety data, and potential risks [2][3].
Despite this mainstream opposition to custom-compounded bioidentical hormones, they remain popular with a subset of physicians and patients, and the number of prescriptions has been on the rise in recent years.
Bioidentical hormones can be compounded into creams, gels, lotions, capsules, lozenges, and injections.
- Bioidentical estrogen (estradiol/E2) is frequently compounded as a cream, gel, suppository, lozenge, or capsule. It can also be combined in Biest (a combination of E2 and estriol/E3) and Triest (a combination of E1, E3, and estrone/E1.)
- The most commonly prescribed forms of compounded bioidentical progesterone include immediate-release and sustained-release capsules, topical creams, gels, and solutions, and vaginal capsules and suppositories.
- Bioidentical testosterone is most commonly compounded into creams, gels, lotions, and injections.
The main benefit of compounded bioidenticals is that they offer highly customizable dosing, allowing for a more tailored treatment approach.
Keep in mind that compounded bioidentical hormones are rarely covered by health insurance. You’ll usually pay out of pocket for these medications, and they are often more expensive than manufactured brand-name hormones available through traditional pharmacies.
Compared to conjugated estrogens and progestin, the primary benefit of bioidentical hormones is their structural similarity to natural hormones. This characteristic is believed to offer several potential advantages over other medications.
Reduced side effects
Because bioidentical hormones closely match the body’s natural hormones, they may cause fewer side effects. Patients often report a smoother transition with fewer unwanted symptoms when using bioidentical hormones compared to alternatives.
Greater patient satisfaction
Patients report greater satisfaction with hormone replacement therapies that contain bioidentical estrogen and progesterone compared to non-bioidentical hormones.
Perceived naturalness
Some people prefer bioidentical sex hormones because they are derived from plant sources and are perceived as a more natural approach to hormone therapy.
Improved efficacy
Some studies suggest that bioidentical sex hormones may be more effective at treating menopausal symptoms and other hormonal imbalances compared to other hormone medications.
Potentially lower risk of breast cancer and cardiovascular disease
Bioidentical hormones may be associated with a lower risk of breast cancer compared to the increased risk linked to conjugated estrogen and synthetic progestins. Bioidentical hormones also appear to have fewer adverse cardiovascular effects compared to non-bioidentical hormones.
In general, research shows that bioidentical hormones may offer advantages over conjugated estrogen and progestin in terms of safety, efficacy, and patient satisfaction. More research is still needed to delineate the differences.
Conjugated estrogen and progestins have some risks:
- Increased risk of stroke, deep vein thrombosis (DVT), pulmonary embolism, and myocardial infarction (heart attack).
- Increased risk of breast cancer, cancer of the uterus/ovaries, and dementia.
- Stomach upset, nausea/vomiting, bloating, breast tenderness, headache, and weight changes.
- Vaginal bleeding, abdominal or stomach pain and tenderness, acid reflux, anxiety, backache, and blurred vision.
The risks of severe side effects like blood clots, stroke, and cancer appear to be related to the form, dose, and duration of use.
Any hormone therapy – including bioidentical hormones -- carries risks, including an increased risk of blood clots, stroke, heart disease, and breast cancer. There is evidence, however, that bioidentical forms of hormones, especially in transdermal form, are safer options.
Whatever type of hormone therapy, the recommendation is to use the lowest effective dose for the shortest amount of time.
We’ve talked about bioidentical sex hormones, but what about thyroid hormones? This is where some confusion comes in because there are two schools of thought.
In one camp are the experts who say that the thyroid medications levothyroxine (synthetic thyroxine/T4) and liothyronine (synthetic triiodothyronine/T3) are bioidentical. Levothyroxine (i.e., Synthroid, Levoxyl, Tirosint) and liothyronine (Cytomel) are designed to have the same molecular structure and be chemically identical to the T3 and T4 produced by the human thyroid gland.
In the other camp are the experts who say that natural desiccated thyroid (NDT) drugs –made from dried and powdered thyroid glands of pigs – more closely resemble human thyroid hormone. Both porcine and human thyroid hormone includes both T4 and T3, as well as T1, T2, and other thyroid cofactors. The ratio of T4 and T3 in NDT is, however, different from the ratio in human hormones.
Because NDT is not synthetically manufactured, it’s often considered more “natural.”
However, theoretically, synthetic thyroid medications could be considered more “bioidentical” than NDT. Because NDT is derived from animal sources and not synthesized in a laboratory, NDT is also considered the more “natural” thyroid hormone medication.
Is one better than the other? We would argue that when it comes to hypothyroidism, the answer is no. The best thyroid hormone replacement medication for you is the one that safely and best relieves your symptoms of an underactive thyroid.
Bioidentical hormones are a promising approach to hormone replacement therapy, with potential benefits stemming from their structural similarity to natural hormones. They can provide relief from perimenopausal and menopausal symptoms, as well as other hormonal imbalances.
If you’re interested in exploring treatment with bioidentical hormones, it’s crucial to consult with a healthcare professional who is experienced in hormone therapy. They can help you understand the risks and benefits, determine if bioidentical hormones are appropriate for your condition, and ensure that you receive safe and effective treatment. As research continues to evolve, a more comprehensive understanding of bioidentical hormones will likely emerge, shedding light on their impact on health and wellness.
For optimal diagnosis and treatment of hypothyroidism that takes into account all your treatment options, consider a Paloma Health membership. Our hormone-savvy practitioners can provide comprehensive care for your underactive thyroid. In many states, you can also access perimenopause and menopause care – including hormone therapy when appropriate – to handle symptoms associated with this hormonal transition. Learn more about a Paloma membership now.