The term “bioidentical” in reference to a hormone means that the hormone molecule being given exactly matches the hormone molecule already present in your body.

The “source” of the hormone is not really important, since the final product is highly purified and there is virtually none of the original material (usually beans) in the final product.

People often say they don’t want “synthetic” hormones, but they prefer “natural” hormones.  I want to say that “synthetic” is not always bad, and “natural” is not always good.  Synthetic is defined as formed through a chemical process by human agency.  That doesn’t mean the end product is not bioidentical.  Bioidentical hormones must be synthesized usually from plant material such as soybeans.  But even if you’re allergic or sensitive to soy, you can still use these hormones, because the purification process ensures that the final product has essentially no soy protein left in it. You can’t go out into nature, and find estradiol or testosterone in large amounts somewhere and put it in capsules or gels or pellets.  It has to either be extracted, purified, concentrated, or synthesized from another molecule that is reasonably close, but not yet the same, structure. So it’s, therefore, not truly “natural”.

So-called “natural” hormones from yams (extracts of the wild yam Dioscorea villosa), etc. are not bioidentical.  The dioscorea from yams may have some progesterone-like effects, but it is definitely NOT progesterone and it should not even be called a hormone. It’s hormonal effects are generally weak at best.

Doctors have already been using bioidentical hormones for years.  They just haven’t been calling them that.  For example, thyroid hormone extract (e.g. Armour Thyroid) from pigs has levothyroxine and liothyronine (T4 & T3), which are the exact same molecules that human thyroids produce, making them also “bioidentical”.  The same is true of Synthroid, which is pure levothyroxine.  Modern insulin is another example of a bioidentical hormone. Nowadays, insulin is made by recombinant DNA technology (Humulog and Novolog) and is exactly the same as human insulin, again, making it “bioidentical”.  The medical profession clearly prefers to use bioidenticals whenever possible, because we want to reproduce the action of the hormone exactly, and minimize side effects or antibody formation to the material being given.

Estradiol is another bioidentical hormone that has been widely prescribed for years.  It is found in Climara and Vivelle patches, Alora, Estraderm, Estrace, Estrasorb, Menostar, Divigel, Vagifem, and Gynodiol.

Prometrium, which is progesterone in peanut oil, is also a bioidentical hormone.  It is my first choice for an oral progestin (chemical that has progesterone effects).  However, even though it is bioidentical, oral progesterone is not always well-tolerated, and it often does not have a strong enough effect on the uterus to prevent or control bleeding that is associated with estradiol replacement. Unfortunately, Prometrium is the only regular prescription form of  oral progesterone currently available.  If you’re allergic to peanuts, you have to try something else.

I think we need to stop talking about “natural” and “synthetic” hormones, and use the more precise term “bioidentical”.

Female hormones that are NOT bioidentical are Premarin, PrePro, Provera, Estratest, Ogen, Ortho-Est, Cenestin, Menest, and Enjuvia.  Since bioidentical estrogens are readily available, these should generally not be used unless really necessary (e.g Aygestin or Provera are sometimes needed when Prometrium won’t work.)

What’s the best delivery system for bioidenticals?

Generally, I try and put the hormones directly into the bloodstream without having to go through the stomach, intestine, and liver first.  This is more physiologic (like normal human physiology) and does not cause adverse effects on clotting factors thus avoiding increasing one’s risk of stroke, heart attack, and venous blood clots.

There are five ways to do that:

1. Subdermal — under the skin as with Pellets
2. Trans-dermal (through the skin as with patches, gels, or creams),
3. Vaginal suppositories or gel
4. Sublingual (under the tongue), or
5.  Intramuscular injection (as with testosterone cypionate which is not quite bioidentical).

Typically, I prescribe either transdermal gels or pellets.  With the gels, you can include estrogens, progesterone, and testosterone all in the same gel.  With pellet implants, you can give only testosterone and estradiol.  The progesterone or other progestin is usually given orally, usually in a cycled manner.  A progestin is required to balance the effect of the estrogen on the lining (endometrium) of the uterus.  If a woman doesn’t have her uterus anymore, the use of Prometrium is debatable.

I prescribe compounded transdermal gels of female and male hormones quite frequently.  With gels, it’s easy to change dosing and you can include 3 or 4 hormones in the gel.  You can also use 2 separate gels, one for the testosterone/estrogen combo, and another for just progesterone.  That would allow for more physiologic cycling if desired.  However, that is more inconvenient and more costly, and the benefits might not exceed the costs.

I use highly experienced compounding pharmacies who have excellent reputations amongst doctors like myself to make up these prescriptions for you.

For convenience and effectiveness, it’s hard to beat hormone pellet implants of estradiol and testosterone.  They are painlessly inserted 2-4 times a year under the skin of the hip. Blood levels are usually excellent, and oftentimes, they work when nothing else has worked.  Oral Prometrium or other progestin must be taken about 2 weeks a month or six days a week if you have your uterus still.

I hardly use sublinguals.  They have to be dosed twice a day and allowed to dissolve under the tongue.

I’m using injectable hormones only for males, and it is called testosterone cypionate. I recommend injecting it once a week to reduce the peaks and valleys in blood levels.

I also have a number of men getting subdermal testosterone pellets on a regular basis with good results.

I do not prescribe HGH (human growth hormone) in my practice at this time.  It’s very expensive and its use is controversial.

For an excellent article on bioidentical hormones out of Harvard, go to