Bioidentical Hormone Replacement

While hormone replacement therapy has been prescribed for many years few people (including doctors) are aware that the hormones contained in the bulk of conventional treatments are in fact artificial, molecularly different to hormones produced natively in the body.

These products demonstrate some of the effects of natural hormones but they are in fact alien to the body and can behave quite differently to the hormone they are intended to supplement. These differences are believed to be responsible for the many reported side effects of conventional HRT treatments.

What Are Bioidentical Hormones?

Bioidentical hormones are hormones that are molecularly identical to those produced naturally by the human body. The term "bioidentical" simply means "biologically identical" — these hormones have exactly the same chemical structure as the oestrogen and progesterone produced by a woman's ovaries.

This molecular identity is what sets bioidentical hormones apart from synthetic alternatives. Because they are structurally identical to the body's own hormones, bioidentical hormones are recognised and metabolised through the same pathways — the body simply cannot tell the difference.

By contrast, synthetic hormones — often called progestins (synthetic progesterone) or conjugated equine oestrogens (derived from pregnant mare's urine) — have a different molecular structure. While they may mimic some effects of natural hormones, they can also trigger responses that natural hormones would not, which is widely believed to be responsible for the side effects associated with conventional HRT.

A History of Bioidentical Hormones

Bioidentical hormones are not new. They have been prescribed since the 1930s, making them one of the oldest forms of hormone therapy available. However, for much of that time they were overshadowed by synthetic alternatives.

The reason is largely commercial. Natural hormones — being identical to substances already found in nature — cannot be patented. Pharmaceutical companies therefore developed synthetic variants with slightly altered molecular structures that could be patented and marketed exclusively. These synthetic versions became the foundation of the conventional HRT industry.

A striking example of these differences is cited by Dr John Lee, one of the prime figures in the natural hormone movement, in his book 'Natural Progesterone – The Multiple Roles of a Remarkable Hormone'. Here he is referring to the difference between the natural hormone progesterone and a commercial HRT product that uses a synthetic progesterone:

'One rather clear example is the fact that progesterone is necessary for the survival and development of the embryo and throughout gestation. Some commonly prescribed progestins carry the warning that their use in early pregnancy may increase the risk of early abortion or congenital deformities of the foetus'.

Dr Lee spent decades researching and documenting the benefits of natural progesterone, and his work has been instrumental in bringing bioidentical hormones to wider medical attention. His books remain essential reading for anyone wanting to understand the science behind bioidentical hormone therapy.

The Women's Health Initiative and the Turning Point

A major turning point in the history of hormone therapy came in 2002 with the Women's Health Initiative (WHI) study. This large-scale clinical trial was investigating the long-term health effects of conventional HRT — specifically, a combination of conjugated equine oestrogens and a synthetic progestin.

The study was halted early when researchers found increased risks of certain serious health conditions among participants. The findings led millions of women to stop taking conventional HRT.

It is important to note that the WHI study used synthetic hormones — not bioidentical ones. Many experts, including Dr John Lee, have argued that the risks identified are attributable to the synthetic nature of the hormones used, not to hormone supplementation itself. This distinction has been a driving force behind the growing interest in bioidentical alternatives.

Natural Sources: Where Bioidentical Hormones Come From

Bioidentical hormones can be sourced from certain kinds of plants and, as the name implies, are identical to bodily hormones. They have been prescribed since the 1930s to treat a range of conditions relating to hormone imbalance with no reported side effects.

The most common plant sources are wild yam (Dioscorea) and soya. These plants contain natural compounds — diosgenin from yam and stigmasterol from soya — that can be converted in a laboratory into hormones that are molecularly identical to human progesterone and oestrogen. You can learn more about this process in our article on yam extract and natural progesterone.

It is worth noting that the body cannot convert raw yam extract into progesterone on its own — the laboratory conversion step is essential. This is why products marketed simply as "wild yam cream" will not provide the same benefits as a properly formulated natural progesterone cream.

Types of Bioidentical Hormones

The two primary bioidentical hormones used in hormone therapy are:


Many women benefit from progesterone alone, particularly if experiencing oestrogen dominance. Others may need both progesterone and oestrogen — this depends on individual hormone levels and symptoms, which is why it is always advisable to discuss your situation with a healthcare professional.

Why Transdermal Cream Is the Preferred Delivery Method

Today growing numbers of doctors are prescribing bioidentical hormones as patients are increasingly demanding alternatives to conventional HRT treatments.

The most effective way to supplement bioidentical hormones is through transdermal cream — a cream applied directly to the skin. This delivery method offers several important advantages:


In particular, natural progesterone has been shown to offer significant benefits for many hormonal conditions, including hot flushes, weight management during menopause, osteoporosis prevention, and gut health. As with any health decision, it is important to discuss your individual needs with a qualified healthcare professional before making changes to your hormone routine.

Wellsprings Bioidentical Hormone Products

Wellsprings Serenity is a premium natural progesterone cream that has been helping women overcome menopause symptoms and other conditions associated with hormone imbalance since 1997. The Wellsprings range includes products formulated for different hormonal needs:


You can compare our bioidentical hormone creams to find the right product for your needs. To understand how bioidentical hormones are viewed by the medical community, read what doctors say about natural progesterone.

On this site you can find out more about natural progesterone and read the stories of just some of the women who have found relief from symptoms of hormone imbalance by choosing Wellsprings Serenity on our customer reviews page.

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