From the Guidelines
Bioidentical hormones typically stay in the body for varying durations depending on their form and administration method, but there is limited evidence on their specific retention times due to the lack of FDA approval and standardized studies 1.
Key Considerations
- The FDA has not approved any type or class of bioidentical hormone therapy for the prevention of chronic diseases in postmenopausal women, and their safety and effectiveness have not been evaluated through the FDA's drug approval process 1.
- The USPSTF did not identify any randomized trials that have studied the potential benefits or harms of bioidentical hormones for the prevention of chronic conditions in postmenopausal women 1.
- Individual metabolism significantly affects how long these hormones remain active, with factors like liver function, age, weight, and concurrent medications influencing clearance rates.
Administration Methods and Duration
- Oral bioidentical hormones generally remain active for 24-36 hours, requiring daily dosing.
- Transdermal patches or creams may last 1-3 days, while pellet implants can provide sustained hormone release for 3-6 months before requiring replacement.
- Injectable forms like estradiol valerate or testosterone cypionate typically last 1-2 weeks.
Monitoring and Safety
- Regular monitoring through blood tests is essential to ensure hormone levels remain within therapeutic ranges, as bioidentical hormones are metabolized and eliminated through the liver and kidneys like naturally produced hormones.
- The lack of standardized studies and FDA approval raises concerns about the safety and effectiveness of bioidentical hormone therapy, and patients should be cautious when considering their use 1.
From the FDA Drug Label
Testosterone esters in oil injected intramuscularly are absorbed slowly from the lipid phase; thus, testosterone cyposterone can be given at intervals of two to four weeks The half-life of testosterone cypionate when injected intramuscularly is approximately eight days.
The duration of bioidentical hormone (BH) retention in the body, specifically testosterone cypionate, is approximately eight days for its half-life, and it can be given at intervals of two to four weeks due to its slow absorption from the lipid phase 2.
From the Research
Duration of Bioidentical Hormone Retention
- The duration of bioidentical hormone (BH) retention in the body is not explicitly stated in the provided studies 3, 4, 5, 6, 7.
- However, study 3 mentions that serum levels of estrone, estradiol, estriol, and progesterone were obtained at multiple time intervals during the first 24-h, and at steady-state, indicating that the study measured the levels of these hormones over a period of time.
- Study 5 reports on the effectiveness and safety of bioidentical hormones for the relief of vasomotor symptoms, but does not provide information on the duration of BH retention.
- Studies 4, 6, 7 discuss the definition, use, and debate surrounding bioidentical hormones, but do not provide information on the duration of BH retention.
Pharmacokinetics of Bioidentical Hormones
- Study 3 compared the pharmacokinetics of compounded bioidentical hormone preparations with conventional hormonal preparations, and found that the area under the curve (AUC) at 24h and at steady-state for estrogens remained consistently lower for all doses of Bi-est tested relative to the patch.
- The study suggests that the currently used doses of compounded hormones yield lower levels of estrogen compared to the standard-dose estradiol patch 3.