Hormone replacement therapy (HRT) can be confusing enough, but it sometimes gets even more so when you’re faced with an array of different products — natural estrogen, equine estrogen, progestin, natural progesterone gel, patches, pills, and so on … all with different names, claims, positives and negatives.
Probably one of the more confusing aspects of HRT is when people talk about synthetic versus natural HRT.
You’ve heard the terms being used — but what do they really mean? What’s natural and what’s synthetic, what are the differences… and what works best?
It can seem complicated, without a doubt, but it’s not as difficult to understand as you might think. In this helpsheet you’ll find an examination of this issue to help you better understand and take charge of your health care.
What are Synthetic Forms of HRT?
This is the type of HRT that has been most widely prescribed for years — estrogens like Premarin and progestins like Provera, as well as low-dose birth control pills.
Synthetics refer to man-made hormones, as you’d expect — hormones that are made from chemical sources that approximate the hormones the human body makes. But it also refers to Premarin (and its offshoots) which, although made from a natural source (horse urine), aren’t the same as your endogenous estrogens (i.e. those made within your body).
So synthetic HRT is similar to that which the body makes; it helps relieve symptoms and prevent long term risks, but isn’t identical to what your body made.
In fact, some synthetic estrogens (such as ethinyl estradiol, found in many birth control pills, and the equine estrogens in both Cenestin and Premarin) are stronger than human estrogens.
Supporters of bio-identical hormones argue that this may cause your liver to work harder than with the bio-identical estrogens. However, this claim has not been proven by the currently available science.
On the plus side, however, synthetic conjugated estrogens (as in Premarin) are the most widely studied form of estrogen — so there has been much more research on its effects in the human body. It’s been shown to eliminate menopause symptoms and help prevent bone loss. In addition, it may help protect against cardiovascular disease, the risk of which is elevated in women with early menopause (source).
Progesterone
For some time the only easily available choice for progesterone replacement was progestin — synthetic progesterone. Progestin isn’t exactly like progesterone, but has many of the same attributes and opposes estrogen in your body like natural progesterone.
On the negative side, since it’s not exactly the same as human progesterone, it may cause side effects similar to premenstrual syndrome (PMS) in some women.
• Synthetic estrogens include: Premarin
What are Natural Forms of HRT?
In most discussions of HRT, “natural” refers to estrogens and progesterone that are often man-made, but from natural plant sources. Most of them are naturally occurring and in theory, bio-identical to the hormones your body makes.
In other words, they don’t approximate your hormones; they have the same exact chemical structure as the hormones made by your ovaries. Supporters argue that, because they are the same as what we make, our bodies should be better equipped to work with them.
An advocate named Suzanne Somers (who appeared on the Oprah Show) has been one of the most vocal supporters of bio-identical hormones, although she’s also received criticism for making unsubstantiated claims regarding their benefits relative to synthetic HRT.
The argument, typically, is that we can more easily metabolize them and break them down so our livers and kidneys can excrete them once they’ve done their work. Given this, they may not accumulate in the body to the same extent, causing fewer side effects.
As with synthetic estrogen, natural estrogens help to eliminate the symptoms of menopause, prevent bone loss and may help protect against cardiovascular disease. However, its unclear whether or not they cause fewer side effects than synthetic estrogen.
Okay, seems pretty straightforward, right? But there is one recent exception to this clear-cut definition:
Cenestin is a conjugated estrogen. It’s natural in that it’s made from plant sources, but it’s not bio-identical to human estrogens. Instead, as a conjugated estrogen, it’s the plant-based copy of Premarin. It’s not horse urine, like estrogen, but the estrogens in it are copies of equine estrogens.
Progesterone
Over the past few years, natural prescription progesterone has become available. As with natural estrogen, it’s plant-based and identical to the progesterone we make. As with the natural vs synthetic debate regarding estrogen, its not clear whether these natural progesterones cause fewer side effects than their synthetic cousins.
• Natural estrogens include: Estrace, Estratab, Ogen, the estradiol patches such as Climara, Alora, Vivelle, Estraderm, Esclim, FemPatch, etc, Tri-Est
• Natural progesterones include: Prometrium, Crinone
What about Phytoestrogens? Aren’t they considered Natural HRT?
Some people do call phytoestrogens — like soy isoflavones and flax seed — natural HRT, but this is not strictly accurate. Generally these substances are considered a substitute or an addition to HRT. HRT, in contrast, refers to prescribed hormones that replace those your body used to make.
That said, phytoestrogens can have an important role to play in managing your early menopause. They may help to minimize certain common symptoms and offer other health benefits as well — for example, in helping to maintain healthy bones and fight the elevated heart disease risk of early menopause sufferers.
For this reason they’re often a good choice even if you’re on HRT. If you’re not on HRT, you can use them to tackle symptoms — even though they’re much less potent than prescription estrogen. At the most, they’re only about 2 percent of the strength of estradiol — the primary human estrogen. Nevertheless they produce an estrogenic reaction in your body.
In fact, it is believed that phytoestrogens can bind to estrogen receptors and mimic the effects of estrogen when your levels are low and also mitigate the effects of estrogen when your levels are already high by blocking the stronger estrogen (i.e. it may act as an “antagonist” of estrogen). In that respect, they may have a role as a balancing agent where your estrogen is concerned.
For more information on phytoestrogens read our helpsheet: What Does The Science Say About Natural Remedies?
Studies have shown potential benefits that include help with symptoms like hot flashes, night sweats and more. Remember though, always consult your doctor before beginning a new regimen or changing your existing regimen.
• Phytoestrogens include: Lignans (found in sources including cereals and vegetables; especially high in flaxseed); Isoflavones (found in legumes; especially high in soy); Coumestans (found in red clover and alfalfa sprouts. A potent phytoestrogen, although still about 200 times weaker than human estrogen).
Natural Versus Synthetic: What’s Best for You?
At this stage you’d be forgiven for tearing your hair out! Why are there no simple answers or quick fixes? Why do I read one thing in books and yet hear a different story from experts? The list of frustrations could go on… It’s important to remember that to date the hype surrounding bio-identical hormones hasn’t been substantiated by high quality studies.
The stated position of reputable organizations such as The Endocrine Society and ACOG is that no credible evidence exists to suggest bio-identical hormones are either more effective or more safe than conventional forms of HRT.
Since the WHI study findings the FDA has required the packaging of both synthetic and bio-identical forms of HRT to carry a so-called ‘black box‘ warning. HRT from compounding pharmacies doesn’t carry this warning, however, this doesn’t imply that it’s safer (only that it isn’t FDA approved).
Ultimately, there’s no clear-cut answer to the question “which is better?” It’s one of those cases where it’s up to you to decide what you’d prefer in conjunction with your doctor.
It really boils down to a personal decision. While some individuals have claimed that naturally occurring forms of estrogen are a better choice because they are exactly the same as the hormones your ovaries produce, many doctors feel more comfortable prescribing Premarin because it has been studied more extensively.
Opinions in this area are notoriously conflicting and those who’ve come out in support of bio-identical hormones have been consistently refuted by others (1, 2, 3, 4).
Along with your doctor, ask yourself: What argument do you agree with? What do you feel comfortable taking? What works for you? There are many ethical, political and practical opinions floating around about HRT and its different forms, but I’m a believer in taking whatever works for you as an individual.
Some women feel uncomfortable taking hormones made of horse urine and have concerns about the treatment of the horses used in the preparation. This is a legitimate concern on their part, and I agree that they shouldn’t take Premarin if that concept bothers them personally.
Others however don’t feel this is a problem — and feel comfortable taking Premarin because it has been so widely studied. This too seems to be a legitimate decision.
In honesty, I think that the different viewpoints all deserve fair consideration. When it comes to health risks, you’ll note that some forms of hormones do appear to be associated with a higher risk than others — but, in this space, there are many unanswered questions and nothing has been unequivocally established.
Written by Kathryn Petras, author of ‘The Premature Menopause Book’. Edited and updated by EarlyMenopause.com.