The study and use of hormones have traditionally been the domain of endocrinology, which focuses on the pathological effects of hormones in the human body. However, there is no specific field of medicine that studies the effects of hormones on wellness and disease prevention. As the field of wellness and disease prevention expands, it is important for primary care practitioners to be knowledgeable about the use of hormones in these areas.

Hormones are essential for maintaining homeostasis, or a state of balance, in the body. They play a role in a wide range of bodily functions, including reproduction, bone health, and mood.

As people age, their hormone levels naturally decline. This can lead to a variety of health problems, including hot flashes, fatigue, and difficulty sleeping. In some cases, hormone therapy can be used to help improve these symptoms.

There is still some controversy surrounding the use of hormone therapy, but the evidence suggests that it can be safe and effective for many people:

Estrogen, Progesterone, and Testosterone

Estrogen, progesterone, and testosterone are the three main sex hormones in humans. Estrogen and progesterone are the dominant hormones in women, while testosterone is the dominant hormone in men. However, both men and women have all three hormones, albeit in different levels.


Estrogen is made in the ovaries, the corpus luteum, adrenal glands, and fat cells. It is a group of molecules, with the three main forms being estriol, estradiol, and estrone.

Estradiol is the most active form of estrogen and is made by the ovaries, adrenal glands, and fat cells after menopause. It has a wide range of effects on the body, including regulating the menstrual cycle, maintaining bone health, and protecting against heart disease.

Estriol is the weakest form of estrogen and is made by the placenta during pregnancy. It has a number of effects on the body, including helping to maintain the health of the vagina and urinary tract.

Estrone is made in fat cells after menopause. It is converted from testosterone in the body and can have some of the same effects as estrogen.


Progesterone is made primarily by the corpus luteum (the follicle that forms after ovulation) and to a small degree by the adrenal glands. It is essential for the menstrual cycle and pregnancy. Progesterone also has a number of other effects on the body, including regulating mood, sleep, and appetite.


Testosterone is made in the testes in men and in the ovaries in women. It is responsible for a number of male characteristics, such as muscle growth, sex drive, and facial hair. Testosterone also has some effects on women, such as increasing bone density and libido.

Hormone Preparations

There are a number of different hormone preparations available, both synthetic and bioidentical. Synthetic hormones are made in a laboratory and are not identical to the hormones that are produced naturally in the body. Bioidentical hormones are made to be identical to the hormones that are produced naturally in the body.

Combination Products

Some hormone preparations contain both estrogen and progesterone. These combination products are often used to treat menopausal symptoms.

Bioidentical Hormone Preparations

Bioidentical hormone preparations are becoming increasingly popular. They are believed to be safer and more effective than synthetic hormones. However, more research is needed to confirm these claims.

Risks and Benefits of Hormone Replacement Therapy

Hormone replacement therapy (HRT) is a treatment that uses hormones to relieve menopausal symptoms and prevent diseases. However, there are risks associated with HRT, including an increased risk of breast cancer and cardiovascular events.

Synthetic vs. Bioidentical Hormones

There are two main types of HRT: synthetic and bioidentical. Synthetic hormones are made in a laboratory and are not identical to the hormones that are produced naturally in the body. Bioidentical hormones are made to be identical to the hormones that are produced naturally in the body.

Studies on Synthetic Hormones

The Women's Health Initiative (WHI) study, which was a large-scale study of HRT, found that synthetic hormones increased the risk of breast cancer and cardiovascular events. The WHI study was stopped early because the risks outweighed the benefits.

Studies on Bioidentical Hormones

There have been no large-scale studies on bioidentical hormones. However, some smaller studies have found that bioidentical hormones may be safer than synthetic hormones.

Female Testosterone 

Testosterone is a female hormone that is less controversial than estrogen, but there is little evidence to support or discourage its use. Testosterone is often nicknamed "the hormone of desire" and promoted in the media as a way to improve libido in aging women. However, there is still much debate about the safety and effectiveness of testosterone therapy in women.

Potential Benefits

  • Increase muscle mass 
  • Decrease visceral fat 
  • Enhance libido 
  • Decrease risk of breast cancer 

Testosterone Replacement Considerations

The safety and efficacy of testosterone replacement therapy in women is still being studied. There is little data on the optimal dosing, method of administration, or duration of treatment. As a result, many women rely on information from the internet and popular literature, which can be unreliable.

Despite the lack of evidence, a growing number of physicians are using testosterone supplementation to improve libido and mood in menopausal women. This is largely due to the popularity of the book "The Hormone of Desire" by Susan Rako, MD, which was published in 1999. The book, along with hundreds of articles in popular science, has led to the perception that testosterone supplementation is a safe and effective treatment for menopausal women.

Male Testosterone 

Testosterone is a primary androgen produced by the testes that plays an essential role in male health. It is responsible for determining male sex characteristics, muscle strength, bone mass, libido, potency, and spermatogenesis.

Androgen deficiency is a condition characterized by low levels of testosterone. It can cause a variety of symptoms, including decreased body hair, reduction in muscle mass and strength, increase in fat mass, decreased hematocrit, decreased libido, erectile dysfunction, infertility, osteoporosis, depression, and mood changes.

Androgen deficiency can occur for a variety of reasons, including testicular or pelvic trauma or surgical removal, hypogonatropic hypogonadism, or normal aging. The normal aging process leads to a decrease in testosterone levels with age, which can result in some or all of the symptoms of androgen deficiency. This condition is also known as andropause.

There is no agreed upon blood level that defines androgen deficiency. However, observational studies have shown that the prevalence of androgen deficiency increases with age in healthy males over the age of 40.

Potential Benefits

  • Improved heart health 
  • Improved mood and overall quality of life 
  • Increased muscle mass 
  • Increased libido 
  • Enhanced energy 

Interested In Learning More? 

As a leader in the field of integrative medicine and bio-identical hormone replacement therapy, Holtorf Medical Group Founder and Medical Director Dr. Kent Holtorf has written an in-depth medical review.

Book Your Appointment 

If you are interested in bio-identical hormone replacement therapy, please contact Holtorf Medical Group today.

Call: (310) 375-2705

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