Maxson, W. S., & Hargrove, J. T. (1985). Bioavailability of oral micronized progesterone. Fertility and Sterility, 44(5), 622-626. https://doi.org/10.1016/s0015-0282(16)48977-6
Maxson WS, Hargrove JT. Bioavailability of oral micronized progesterone. Fertil Steril. 1985;44(5):622-626. doi:10.1016/s0015-0282(16)48977-6
Maxson, Wayne S., and Joel T. Hargrove. "Bioavailability of oral micronized progesterone." Fertility and Sterility, vol. 44, no. 5, 1985, pp. 622-626.
For EndNote, Zotero or Mendeley:
License
No open license is recorded for this paper. Reuse terms are set by the publisher.
Oral micronized progesterone reached mid-luteal levels in 10 people
Oral micronized progesterone peaked at levels not significantly different from mid-luteal levels, a 1985 study of 10 volunteers found. Nine were healthy postmenopausal women. One was a man. Each took a single dose. Blood progesterone peaked at 2.8 hours on average and fell to baseline within a day.
Key Findings
In nine healthy postmenopausal women and one man, blood progesterone reached its peak 2.8 ± 0.35 hours on average after a single oral dose.
Peak progesterone was not significantly different from mean mid-luteal levels in control cycles of seven healthy women with regular ovulatory cycles.
Every subject had a significant rise in progesterone over baseline. The rise lasted at least 6 hours, and levels were back at baseline by 24 hours.
Estradiol, FSH, LH, cortisol, aldosterone, lipids and liver enzymes stayed without significant change across the 24 hours of observation.
No major complications were reported during the 24 hours. Three women felt drowsy. One reported worse hot flashes at 24 hours. Stomach and bowel side effects were not reported in that time.
Interpretation
The study measured one oral dose in 10 volunteers over 24 hours. Nine were postmenopausal women, five of them taking estrogen, and one was a man. No cycling women took the drug. The report contains blood levels and short-term lab safety results. It has no pregnancy, symptom or luteal-support outcomes. Absorption varied widely between people. Higher progesterone peaks went with higher estradiol, and the authors say the effect of estrogen on oral absorption is unknown. An accurate comparison with earlier oral preparations is not possible because the assays differed. The authors state that long-term studies are required to judge clinical efficacy and side effects.
RRM Context
RRM treats progesterone as the hormone that follows ovulation. The paper keeps natural progesterone apart from synthetic progestins. It names side effects of some progestins, such as depression and headaches. Only women past menopause and one man took the dose. Cycling women were not tested.
Our editorial summary of this paper, not the article's abstract.
Abstract
Progesterone (P) has not been administered orally because of reportedly poor bioavailability and a rapid clearance rate. Unfortunately, the synthetic derivatives, although orally active, have a number of disadvantages and fail to mimic natural P completely. To investigate the bioavailability and short-term toxicity of oral micronized P, a standardized dose of 200 mg of micronized P was administered to nine healthy postmenopausal women and one male subject. Serial determinations of serum P concentrations demonstrated rapid absorption of P. Peak concentrations of P rose from a negligible baseline level to 17.0 +/- 4.9 ng/ml at an average of 2.8 +/- 0.35 hours after administration. The peak concentrations of P were equivalent to those observed in the midluteal phase in normal control cycles (14.1 +/- 2.7 ng/ml). All subjects exhibited significant elevation of P over baseline levels that persisted for at least 6 hours after the single oral dose and returned to initial levels by 24 hours. There was no significant change in estradiol, follicle-stimulating hormone, luteinizing hormone, cortisol, aldosterone, lipids, or hepatic enzymes during the 24-hour study interval.
05dq2gs74 