| History
& Overview: Natural progesterone has been used as a
cream for over 20 years. The
USP progesterone used by some advocates for hormone
replacement originates from plant fats and oils.
Typically a plant sterol called diosgenin, which is
derived from a wild yam that grows in Mexico, serves as the precursor to
progesterone. Also, diosgenin
can be procured from soybeans.
| While structurally
dissimilar to synthetic progesterones, natural progesterone is
identical to progesterone made by the corpus luteum and placenta.
Both the plant origin and structural similarity to endogenously
manufactured progesterone allow these creams to be marketed as
"natural". |
|
| Pharmacokinetics: In the normal female
follicular plasma levels of progesterone are under 4nmol/L. Median
levels during luteal phase are roughly 15nmol/L while peak 21 day values
range from 35-45nmol/L. |
Very limited
data exist on the
absorption and subsequent, if any, plasma levels of natural progesterone.
In a randomized, placebo
controlled, crossover study of 20 subjects,
all status post oopherectomy and hysterectomy, topical progesterone failed
to elevate plasma levels anywhere near physiologic ranges.
Further studies
have also failed to demonstrate a significant increase in plasma
progesterone levels. Levels of only 5.3nmol/L were achieved in an open
randomized study of 24 healthy postmenopausal women over six weeks. |
|
Clinical
Effects: Preliminary,
non-controlled data, weekly hint that natural progesterone may protect
against osteoporosis. Proposed mechanisms include stimulation of
osteoblast proliferation.
Animal studies also show that natural
progesterone may decrease trabecular bone resorption.
|
NOTE:
It
should be noted that word natural is commonly a euphemism for
unregulated or unproven. Any product that meets the following nebulous
definition can be considered natural:
“Any product whose principal
ingredients are of animal, vegetable, or mineral origins fits the legal
definition, though it may in no way resemble the ingredients in their
natural state.” |
|
| Dose and
Costs: Natural progesterone creams possess 1.5 - 3%
concentrations of progesterone. Doses of 10 - 40mg are advocated for
topical administration. One tube typically lasts for up to 3 months. |
Progesterone
creams
are
purported to be absorbed through the skin. From the skin, it is theorized,
that the hormone crosses into bloodstream through the capillaries.
Physical sites deemed superior for absorption are the face, neck, chest,
breasts, inner arms and palms of the hands. It should not be placed
on the skin where other topical agents have previously been applied.
|
Side
effects: Acne,
skin irritation, weight gain, weight loss, vaginal spotting or bleeding.
Contraindications:
severe hepatic disease. |
|
