All Supplement Orders over $50 Receive Free Shipping!
Holiday Special! Immune Health Gift Pack. Click Here to view the supplements.

Bioidentical Progesterone Protects Against Breast Cancer – Part 2

Bioidentical Progesterone Protects Against Breast Cancer – Part 2

The TRUTH – They Still Do Not Understand The Difference!

Progestin vs. Progesterone

The “HRT” referred to in this NEWS is Prempro. These drugs are a combination of a synthetic estrogen (Premarin) and synthetic progestin (Provera).

This is not NEWS although it did reinforce the fact that synthetic progestin is bad for women.

In fact, we might argue that a “leading cause of breast cancer” is the lack of knowledge about the difference between synthetic progestins and bioidentical progesterone. Why?  Because this lack of knowledge may stop many women from taking bioidentical hormones that help them reduce the risk of breast cancer and other forms of cancer and greatly benefit their quality  of life.


Truth: *Studies show that natural (bioidentical) progesterone protects against Breast Cancer.

At NBH Lifetime Health, we have known for years that the combination of synthetic estrogen and synthetic progestins (prempro) increases the risk of breast CANCER? This is NOT NEWS. It is based on numerous studies and clinical experience. Natural Progesterone (bioidentical) protects against breast cancer.

2010: Neal Rouzier, M.D. Progesterone and Cancer

•         *Most down regulation of breast tissue is in luteal phase when progesterone is at its peak.

•         *Highest breast protection against cancer is at the end of pregnancy when progesterone is maximum.

•        * Progesterone protects breast tissue.

•         *Provera blocks this protection and stimulates breast tissue.


2002: Eur J Cancer Prev., 2002 Oct; 11(5):481-8

  • Growth inhibition of human breast cancer cells by progesterone is due to P13-kinase/AKT pathway causing apoptosis (death) of breast cancer cells.
  • Progesterone was shown to inhibit proliferation of normal breast epithelial cells as well as breast cancer cells.

2001: The Women’s Health Initiative Study of 2000 referred to in the latest “news flash” involved post menopausal women who were not on biodentical hormone replacement or even estrogen replacement. The average age was 63. For these women, the risk of developing breast cancer was as follows: (1.00 is baseline).

  • Incidence of breast cancer on HRT was: RR-1.26 (Increased risk over baseline)
  • Incidence of breast cancer on ERT was: RR-0.57 (Decreased Risk: ERT is Estrogen alone without progestin).


2000: “Adding a progestin to estrogen markedly increases the risk of breast cancer 29% over baseline.” 2000: J. Natl Cancer Inst 92 (4): 3280332, 2000

2000: Progestins dramatically increase risk of breast cancer 8 times over baseline.
JAMA 2000;203: 485-491

1999: Proc Natl Acad Sci USA 1999 Mar 2; 96(5):2520-5

  • Full term pregnancy is the most effective natural protection against breast cancer.  Because the mammary gland is exposed to the highest physiological concentrations of hormones during full term pregnancy, it is these elevated levels of hormones [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][progesterone and estrogen] that likely induce protection from mammary cancer.

1998: Am Clin Lab Sci 1998; 28:360-369

•         Progesterone at high levels exhibits a powerful anti-proliferative effect on breast cancer cell lines.

•         Progesterone inhibits growth and induces apoptosis (death) in breast cancer cell.


1995: Fertility Sterility 1995; 63: 785-91

•         Estradiol stimulates milk duct tissue 230%.

•         Progesterone (not progestin) decreased proliferation rate 400%.

•         Evidence that unopposed estrogen stimulates hyperproliferation of breast epithelial and progesterone protects against hyperproliferation.


1993: Mayo Clinic Women’s Health Source. August 1999, p.3

•         Mayo Clinic study evaluated benefits of natural progesterone over synthetic progestins.

•         Progesterone reduced hot flashes, depression, abnormal uterine bleeding.

•         Quality of life and satisfaction with HRT greatly improved with progesterone over Provera.

•         Source of problems with progestins is metabolic breakdown products causing side effects; none with progesterone

1999: Am J Obstet Gyn, Jan 1999;180:42-48

•         The incidence of side effects on estrogen alone were reduced when natural progesterone was added.

•         Psychological effects, bloating, edema, nausea were reduced with the addition of micronized progesterone.

•         Unexpected feeling of well being was observed when progesterone was added to estrogen.

•         Progesterone improved well-being. Provera did not improve well-being.


1985: Japan Journal of Cancer Research 1985; 76: 669-04

  • Estrogen sensitive mammary tumors were reduced equally by either Tamoxifen or progesterone (not progestin).
  • Inhibitory effect of progesterone was attributable to interference with binding of estrogen to estrogen receptors on target cells.
  • Studies strongly suggest progesterone offers a safer approach to HRT than progestin

1981: American Journal of Epidemiology 1981; 114:209-217

  • Researchers at Hopkin’s studied 1083 women for breast cancer.
  • Results showed risk of breast cancer 50 times greater in subjects with low progesterone levels.
  • 10 fold increase in death from neoplasms with low progesterone levels.
  • Hormones and Cancer Risk

Article By Labrix Labs /Hormone Replacement and Cancer Risks

“Patients often have questions regarding hormone replacement and cancer risks.  While not all cancers are influenced by hormone levels, malignancies that arise from hormone sensitive tissues often are.  These hormone sensitive cancers include ovarian, endometrial, breast and prostate cancers.

One of the primary risk factors for endometrial cancer is unopposed estrogen. This relationship came to light in the years following the introduction and widespread prescription of conjugated estrogens (Premarin) to millions of women in the US, resulting in an eight-fold increase in endometrial cancer.

Since 1976, Premarin, and other medications that contain estrogen are required to carry a label warning about the risk of endometrial cancer. Conventional prescribing practices have been changed to include a progestin along with estrogen for women who have not had a hysterectomy.

The primary progestin prescribed to most women in this situation is medroxyprogesterone acetate (Provera), a synthetic molecule that binds to progesterone receptors in the endometrium, but does not have the same effects in the rest of the body.  While Provera may reduce the risk of endometrial cancer, it has multiple side effects including an increased risk of breast cancer and cardiovascular disease.


The impact of medroxyprogesterone acetate along with conjugated estrogens was not fully understood until 2002 when one arm of the Women’s Health Initiative was halted prematurely due to the increased incidence of breast cancer, heart disease and strokes in the study subjects.

At this time millions of women stopped taking hormones altogether, and the information that came from this study has left many patients and their health care providers confused about hormone replacement and the potential effects.

[Insert: Many women stopped taking estrogen after the NEWS of the Women’s Health Initiative, their fear preventing them from taking a bioidentical estradiol that helps protect against all of the following:]

  • Heart Disease
  • Strokes
  • Osteoporosis
  • Alzheimer’s Disease
  • Urogenital atrophy
  • Menopausal symptoms (hot flashes, depression, mood swings)
  • Macular Degeneration
  • Colon Cancer
  • Tooth Loss

Estrogen Deficiency Can Contribute to the Following:

•          Heart Disease

•          Strokes

•          Alzheimer’s Disease

•          Colon CA

•          Vaginal Atrophy

•          Urinary Incontinence

•          Menopausal hot flashes

•          Tooth Loss

•          Macular degeneration

•          Osteoporosis

•          Depression & mood swings

•          Sexual dysfunction

•          Skin atrophy

•          Sleep disturbances

•          Decreased sense of well being

When exploring the relationship between hormones and cancer it is important to distinguish between the various types of hormones and to look at their relationship to each other.  Estrogen is a proliferative hormone, and causes growth of the endometrium, breast tissue and development of ovarian follicles. Progesterone plays an important role in supporting the differentiation and complete development of these tissues.

When there is not sufficient progesterone to balance these effects of estrogen, there is an increased risk of uncontrolled growth, or cancer. This is especially true for exogenous hormones that are foreign to the body such as Premarin, but is also true for increased endogenous production.  For example, women who have an early menarche or late menopause have an increased risk of breast cancer as do women who are overweight, as fat tissue is a source of estrogen.


Though synthetic progestins and progesterone have similar sounding names and act on the same receptors in the body, their differences far outweigh their similarities.   After the WHI report in 2002, a French study of 100,000 women, compared women using an estrogen and progestin combination with women who were using estrogen and progesterone.


Researchers found a significant increase in the incidence of breast cancer with women in the progestin group and no increase in the group using progesterone when compared with controls.

Influences of percutaneous administration of estradiol and progesterone on human breast epithelial cell cycle in vivo. Chang KJ, et al. Fertil Steril (1995) 63(4):785-91.

Breast Cancer Risk in Relation to Different Types of Hormone Replacement Therapy in the E3N-EPIC Cohort. Fournier A et al. Int J Cancer (2005); 114(3):448-54.


If you have questions regarding the use of synthetic hormones and the benefits of  bioidentical  hormone therapy, please contact NBH Lifetime Health. For a location near you, visits

If you have any questions, please email us at


Share this post:

Scroll to Top