By Karen Hales, Neurology Solutions contributing writer

Neurology Solutions has administered hormone therapy to approximately 80 Parkinson’s disease patients over the past two years to improve patients’ cognition, mood, and mobility, and increase their tolerance for exercise. Nearly all of the current HRT participants also use Deep Brain Stimulation therapy (DBS) to address motor symptoms. The frequency of DBS patients’ visits allows for consistent and thorough monitoring of the individuals’ hormone levels. Approximately half report benefits ranging from noticeable to remarkable.

Following is a Hormone Therapy Q & A with more details on Neurology Solutions’ approach and results.

Hormone Therapy for Parkinson’s Q & A

Why use hormone therapy in treating Parkinson’s?

Sex plays a role in the risk of developing PD, with a relative risk of 1.5 in males compared to females. Risk of PD is lower in women with more lifetime estrogen exposure, including those who have had multiple pregnancies, a history of estrogen birth control and hormone replacement therapy. There are multiple types of bioidentical estrogens present in the human body. Two types of estrogen include estradiol and estriol. Animal studies suggest that estradiol maintains the dopaminergic system and may be neuroprotective in PD.

Typically, in healthy males, testosterone level is the maximum in the mid-30s, which then drop about one percent each year. A sudden decrease in testosterone may be tied to the increased prevalence of Parkinson’s in men. Researchers have begun to study the impact of testosterone deficiency related to development of PD symptoms on male mice and have found that castrated mice begin to develop a pathology similar to PD, which is reversed with supplements in the form of 5-alpha dihydrotestosterone (DHT) pellets. (However, there is not currently a reliable animal model for the study of Parkinson’s disease.)

Hormone Therapy and Neurodegenerative Disorders

Parkinson’s disease is the most common neurodegenerative disease next to Alzheimer’s, affecting some 1 million Americans and approximately 5 million individuals worldwide. Degeneration of neurons that regulate production of dopamine and loss of striatal neurons is a characteristic of PD.

Neurotrophic growth factors act on certain neurons of the central nervous system and the peripheral nervous system and support the survival of existing neurons. Growth factors are proteins that encourage the growth of new neurons and synapses in the brain. They are active in the hippocampus, basal forebrain and frontal cortex, the area of the brain responsible for planning complex cognitive behavior, personality expression, decision making, and moderating social behavior.

“Hormone replacement therapy is one way to increase growth factors, particularly GDNF (glial cell line-derived neurotrophic factor),” Dr. Izor said. “Estrogen seems to stimulate pathways in the brain and stimulate GDNF, which has been associated with neuroprotection in PD animal models.”

Likewise, exercise that achieves a sustained 60 to 80 percent maximum rate has been shown to activate brain-derived neurotrophic growth factors and reduce PD symptoms by nearly 30 percent.

What hormones are used in this therapy?

Estrogen receptors are abundant in the brain, and estrogen is known to play a role in many brain processes.

There are three different forms of the hormone we commonly refer to as “estrogen.”

  • Estradiol is the major estrogen produced by ovaries and is the strongest potency.
  • Estrone is considered a weaker form of estrogen. It is typically produced by special belly fat cells.
  • Estriol is the lowest-potency form of estrogen; it is approximately 8 percent as potent as estradiol and 14 percent as potent as estrone. Recent research indicates estriol may have an anti-aggregation affect on a-synuclein, a major player in the progression of PD and Lewy body dementia.

Progesterone is produced in the ovaries and placenta and plays a role in maintaining the menstrual cycle and pregnancy. Progesterone influences sleep quality and has other relevant functions in both men and women that are not very well understood.

Testosterone is the principal hormone that differentiates the development of men from women and manages the appearance of male characteristics.

For women, Neurology Solutions is using a combination of estradiol, estriol and testosterone, administered as a compounded cream. Progesterone may also be compounded in the cream or given orally.

For male patients, Neurology Solutions has prescribed testosterone compounded cream or injection, depending on the patient’s individual preference, medication cost and actual outcomes of therapy. Since increasing estrogen levels can mask the benefits of testosterone therapy, some patients also receive an estrogen blocker such as anastrozole or letrozole, which inhibits the conversion of testosterone into estrogen. Neurology Solutions is also exploring the use of estriol (the lowest potency estrogen), which is believed to be a protective estrogen for PD.

What are Bioidentical Hormones?

Bioidentical hormone replacement therapy (HRT) is the preferred mode of hormone replacement therapy by Neurology Solutions as the human-derived supplements have less risk for side effects or complications than animal-derived or synthetic hormones. Bioidentical hormones are synthesized from plant chemicals extracted from yams which mimic the structure of human endogenous hormones. Bioidentical hormones include: estrogens (17 beta-estradiol, estrone, and estriol), progesterone, testosterone and DHEA.

What are the risks of Hormone Replacement Therapy?

Risks of hormone therapy may include heart disease, stroke and blood clots. An increased risk of breast cancer has been identified as associated with hormone therapy using Premarin, which is a synthetic hormone derived from pregnant horse urine. However, a correlation between an increased risk for breast cancer and hormone therapy has not been consistently found with the use of bioidentical hormones. A 10-year French study of 1,555 menopausal women called the E3N Cohort studied the use of a low-dose estradiol patch plus oral progesterone and showed no increase in risk for breast cancer, strokes or heart attacks.

Who should avoid hormone therapy?

Neurology Solutions does not attempt the treatment on patients who have had breast cancer or endometrial cancer or men who have had prostate cancer without the prior approval of their oncologist. Individuals who have suffered strokes or blood clots to the legs or lungs are considered on an individual basis for bioidentical hormone therapy. All patients are closely monitored to prevent potential side effects, including risk of stroke, blood clots and prostate or breast cancer.

What Results Have Parkinson’s Patients Realized with HRT?

In approximately 50 percent of patients treated with bioidentical hormones by Neurology Solutions, the benefits have ranged from worthwhile or measurable to remarkable. The length of time to ascertain the benefit of HRT varies as it is dependent upon optimization of both the patient’s testosterone and estrogen hormone levels.

In the group whose benefits are measurable, patients have demonstrated increased energy level, exercise tolerance and recovery, cognitive performance, and modest improvement in sexual function and libido. As high estrogen has been linked to truncal obesity, optimization of hormones has also improved weight loss efforts for patients struggling with obesity. Some females report reduced vaginal dryness with use of estrogen cream. In addition, research has shown estrogen therapy can improve bone density.

For the 10-15 percent of patients whose benefits have been most dramatic, the reported benefits include some or all of the following: improved fine motor control, faster gait speed, better gait initiation, improved fluidity in standing from seated position, and improvement in libido, erectile function and/or overall constitution, such as less fatigue and having more energy, increased strength and endurance.

Exercise is known to have neuroprotective benefits for PD, and exercise alone can lessen PD symptoms by as much as 30 percent. Neurology Solutions’ speculates that because the majority of patients reporting positive benefits with BHRT experience increased energy levels and tolerance for exercise, they also are benefiting from a more active and fit lifestyle, including improved mood, sleep and energy.

“They have improved mobility, they have more energy, they have more tolerance for exercise,” Izor said. “Some patients even have reported a decrease in the amount of tremor they feel.”

What Would Hormone Replacement Therapy Entail?

As adjustments in hormones are made based on lab work and patient interview, lab work and medication adjustment cannot be done over the phone. eurology Solutions attributes the patient-reported benefits of HRT for the management of PD to the ongoing optimization and close monitoring of its patients’ hormone levels. Therefore, Neurology Solutions requires monthly lab work and follow up visits for participants in its HRT program until hormone levels are optimized and remain consistent for several months. Once stable, quarterly lab work will continue to be performed to ensure levels remain within therapeutic windows.


Neurology Solutions is accepting new patients seeking a specialist in managing Parkinson’s disease, dystonia, essential tremor and age-related movement disorders. If you would like a consultation for managing symptoms of a movement disorder, please contact Neurology Solutions or call 512-865-6310 to schedule an appointment.

Stay informed by frequenting Neurology Solutions’ blog, or join Neurology Solutions Movement Disorders Center’s e-mail list to stay up to date on the latest in treatments and how to manage stress, stay healthy and maintain quality of life while living with a movement disorder.