natural or synthetic HRT
Monday, 21 June, 2021

Synthetic, Body Identical & Bioidentical HRT – What’s the difference?

Author: Susie Perrie Debice

Tempted by Hormone Replacement Therapy (HRT) to help smooth over your raging menopausal symptoms, but concerned and confused about the safety of these prescribed hormones? Food Scientist and Nutritional Therapist Susie Debice explains why body identical is by far THE safest HRT available today, giving you peace of mind so you can gain the hormone support your body is craving.

When HRT was first produced in the 1960’s it was produced from the hormone precursor pregnenolone which was extracted from horse (mare’s) urine and prescribed as a pill called Premarin which contained high doses of synthetic oestrogen.

HRT has thankfully evolved in many ways and nowadays the starting material for hormones found in the more modern forms of HRT commonly prescribed today are plant based, extracted from yam or soya.

Combined Approach

Over the decades, studies have revealed that the safer way to prescribe HRT is to always combine oestrogen with protective progesterone and use lower doses, more in line with the levels that your body is used to. But the safety of HRT isn’t just about dose and hormone combinations, the safety of HRT also depends upon the shape (chemical structure) of the hormones themselves.  

Synthetic vs Natural

You may have heard that synthetic HRT is dangerous, and body identical HRT is safe, or you may have read that all forms of HRT are unsafe if taken for longer than 5 years. All of these myths and rumours have created a great deal of confusion around HRT which may be preventing you from talking to your doctor about HRT. You may even feel judged by your friends or family for what’s often described by some women as ‘resorting’ to taking HRT rather than being able to manage your menopause naturally.

There’s no shame in taking a prescribed hormone to give yourself an easier menopause, it’s quite the opposite! Taking, the right type of prescribed hormones, at the right dose, is actually a really positive step for alleviating your menopausal symptoms and supporting your long-term health.

To help you understand how and why, let’s take a deeper dive into the difference between synthetic, body identical and bioidentical hormones so that you can make an informed decision when talking to your doctor about hormone support.

Synthesised – Made in a Lab

Don’t go getting confused about the meanings of the words synthesised and synthetic. All hormones found in HRT whether they are synthetic, body identical or bioidentical are synthesised. This simply means they have been made in a laboratory. What determines if they are natural (body identical) or synthetic is their shape, also known as their chemical structure.

Each hormone has a very specific chemical structure, a set shape that fits into a special docking site known as a receptor site present on all cells that interact with hormones. While sitting in this docking site, found on the surface of a cell membrane, the hormones can pass over the sets of instructions that instigate certain changes in cell activities. This is how hormones influence your cycle, mood, energy and play an integral role in your general health and wellbeing.

Body Identical Hormones

Body identical hormones have exactly the same chemical structure (shape) as the natural hormones that your body naturally produces (or used to produce before the menopause kicked in). This means that your body can’t tell the difference between the body identical hormones that you are taking and the hormones that it produces itself – they are identical in every way. These body identical hormones are the most natural way of taking HRT.

Synthetic Hormones

All the early forms of HRT and most of the prescribed forms of HRT today contain synthetic hormones, known as conjugated oestrogens or progestins. These synthetic hormones have been made in a way that gives them a very slightly different chemical structure to the hormones the body naturally produces.

The shape is similar enough to fit into the receptor sites but the slight change in shape means that the instructions passed over to the cells are a little different. Why is this significant? Turns out that the very subtle difference in chemical structure tends to be associated with a heightened level of impact on body cells and this creates sides effects and increases the likelihood of risk factors that you need to be aware of.

Side Effects and Risk Factors of Synthetic Oestrogen 

Synthetic forms of oestrogen found in some HRT tend to have a much more powerful and potent impact on body cells, are present at much higher doses than the body is used too and often cause side effects such as headaches, migraines, digestive issues, breast tenderness, excessive bleeding, endometrial lining proliferation, etc. If prescribed without protective progesterone then risk factors such as heart disease, endometrial cancer and breast cancer may also be a factor. This is why doctors now prefer prescribing a combined synthetic HRT, rather than a synthetic oestrogen-only HRT.

Oestrogen – Pill vs Transdermal

When synthetic oestrogen is taken as an oral pill, large amounts of synthetic oestrogen suddenly rush into the bloodstream and this triggers a response in the liver which activates the liver to produce clotting factors, increasing the risk of clots, stroke and deep vein thrombosis. However, transdermal oestrogen tells a very different (and safer story). Oestrogen applied to the skin, slowly travels through the adipose tissue under the skin before trickling into the bloodstream, similar to the way your ovaries would trickle oestrogen into your bloodstream. This slow steady absorption across the skin avoids triggering a response in the liver. Fortunately, many of the transdermal oestrogen HRT medications now contain body identical rather than synthetic oestrogen.

Body Identical Oestrogen

As HRT has evolved the body identical forms of oestrogen are becoming much more available for NHS doctors to prescribe as transdermal patches, gels or sprays. The benefits of switching from synthetic hormones to body identical hormones are lower levels of risk factors and lower doses that are more in line with the levels of hormones that your body naturally produces.  

Commonly prescribed body identical forms of oestrogen available on an NHS prescription containing oestradiol (made from yam or soya) include

  • Estrogel - gel in a pump bottle, very low dose, only lasts in your body for about a day so you don’t get any build and side effects are unlikely
  • Sandrena - a gel in single dose sachets, again ow dose.
  • Lenzetto - a spray containing a higher dose than the gels, which you just spray onto your skin and leave to dry.
  • Patches – there are lots of body identical patches available, offering a range of doses.

Synthetic Progesterone

You can spot a synthetic form of progesterone by its name as these are called progestins instead of progesterone. Like the synthetic forms of oestrogen, these progestins also have a different chemical structure to the progesterone that your body naturally produces. Examples of synthetic progestins in HRT include dydrogesterone, medroxyprogesterone, norethisterone, levonorgestrel and the Mirena coil.  

Side Effects and Risk Factors for Synthetic Progesterone

Some synthetic progestins may make you feel tired, moody and spotty, not what you need during your menopause. Women with migraines are not suited to taking progesterone and too much progesterone may also make your breasts feel sore and tender. Studies highlight risk factors associated with taking synthetic progestins to include increased risk of blood clots, heart disease, high blood pressure, high cholesterol, and breast cancer.

In the case of breast cancer, this does depend on how many of the other risk factors exist – these include not exercising, drinking alcohol, being overweight or obese, poor diet, family history of breast cancer and poor quality and poor quantity of sleep.

Body Identical Progesterone

Thankfully, there is now a highly effective form of body identical progesterone available on an NHS prescription. This means that if you are using one of the body identical forms of oestrogen (gel, patch or spray) then you can now achieve a combined HRT (oestrogen + progesterone) approach, which is what’s been shown to be the safest and most effective menopausal hormone support.

Progesterone is hard to absorb across the skin and difficult to absorb in the gut, which is why it’s taken longer for a body identical form of progesterone to become available. However, Utrogestan uses a special micronized oral form of progesterone which is readily absorbed.

Studies have shown that body identical forms of progesterone do not increase the risk of blood clots or heart disease and actually help to lower blood pressure and cholesterol. Taking progesterone is important as it helps to balance out the effects of any oestrogen you are taking and protect your womb lining.

Bioidentical Hormones

There are a small number of private doctors and private labs offering a very expensive and seen to be exclusive bespoke service of bioidentical hormones. From a saliva sample or a blood test, a formulation is developed that aims to match your hormone profile and hormone requirements. These preparations contain oestrogen (oestradiol, oestriol, and oestrone) alone or in combination with progesterone as a combined pill or as an oestrogen lozenge and a progesterone cream.

However, this does not take into account the risks associated with taking an oral oestrogen or the complications of absorbing progesterone across the skin. There are often other hormones and precursor compounds included such as testosterone, dehydroepiandrosterone (DHEA) and pregnenolone and because these medications aren’t standardised or regulated then you may get a different dose with different batches, making it harder for your body to benefit from a baseline of hormone support.

The other point to note is that by the time you reach the menopause, the way your body makes its own hormones may have become tired and flawed, so this isn’t really what you want to be matching! Now that body identical hormones are widely available on the NHS, it’s highly recommended that you swap these expensive and unregulated bioidentical hormone preparations for the safe, affordable, and regulated body identical HRT, readily available from your doctor.

When not to take HRT

When you have an oestrogen receptive breast cancer, or if you have a history of blood clots or your family has a history of blood clots. In these situations, there are other ways to support your hormones including switching to a healthy diet and lifestyle, improving your exercise and fitness, taking specific nutritional supplements, and using mindfulness or cognitive behavioural therapy to help manage stress and anxiety.

How long can you take HRT?

There is evidence to suggest that if you are taking synthetic hormones for longer than 5 years this starts to increase the likelihood of risk factors. However, taking the body identical hormones is thought to be incredibly safe and is now seen by many doctors as a long-term prescription (for decades) to help protect women from many of the degenerative diseases that tend to be accelerated by the menopause – osteoporosis, dementia, Alzheimer’s and many more.

So, if you are struggling with your menopausal symptoms then book an appointment with your doctor to discuss your options for supporting your hormones with a body identical prescription.

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