Perhaps 80% of all progesterone creams in the market place have some kind of chemical or herb that is estrogenic or progesterone blocking. For instance, many progesterone creams commonly have aloe. Aloe is traditionally used to create a miscarriage during the first trimester of pregnancy. If you take enough aloe during the first trimester of pregnancy, then you can create a miscarriage. Sufficient levels of progesterone are needed to maintain a pregnancy. If you do not have enough progesterone, this will generate a miscarriage. If aloe causes a miscarriage, it is likely to be a progesterone blocker. Why would anyone put aloe in a progesterone cream?
Rosemary is a known phytoestrogen or plant estrogen. Sometimes progesterone cream manufacturers will put rosemary into a progesterone cream for the estrogen effect. This may work well for hot flashes. However, if you are trying to get rid of a fibroid this would make the fibroid bigger. Sometimes rosemary is added for its anti-oxidant effect. However, rosemary is very estrogenic and makes many women's Estrogen Dominance much worse. Lemon grass oil (not the citrus) a common pleasant scent added to progesterone creams is also estrogenic.
A cream is just water and oil mixed together. To keep the water mixed with the oil, an emulsifier is used. The progesterone is in the oil; it is not in the water. Then a thickener is added to make the cream thick. Water is absorbed into the skin and the oil keeps the water locked into the skin. The problem is that once water is added into the cream an appropriate preservative must be added to keep bacteria out of the the water. If there is no water then no preservative needs to be added.
Some preservatives such as parabens and phenoxyethanol are very estrogenic and give my patients problems. For those of you that took organic chemistry, it seems that anything with a benzene ring in it should be suspect as a hormone disrupter. As you recall, benzene rings are nicknamed aromatics. Thus, anything that is aromatic including natural herbs should be suspect as hormone disrupters. Other preservatives such as stearyl Konium Chloride are down right toxic. 3ccs of Stearyl Koniium Chloride taken orally causes fatal convulsions in adults. Even something as innocuous as grapefruit seed extract is being fingered as being converted to a toxic quartenary ammonium chloride by a University professor. He ran a Mass Spectrometry chemical analysis on the grapefruit seed extract.
Some creams also may contain mineral oil that blocks the absorption of progesterone through the skin. Soy lecithin is also a common emulsifier in progesterone creams that John Lee, MD frowned upon for its possible hormone disruptive effects. Soy lecithin is used in chocolates to keep the oil and water mixed together and is frequently used in "liposomes" in progesterone cream. In reality, progesterone does not need liposomes to be absorbed. Since progesterone is fat soluble it needs very little help to cross the skin.
The correct dosage for the progesterone cream should be between 500 mg/oz and 1000 mg/oz. Again remember that a cream has about 1/2 the volume of water and 1/2 the volume of oil. The progestone is oil soluble and is in the oil portion of the cream, not the water portion.
Dr. Lee explained much higher doses are given the excess progesterone is metabolized in the liver and some of the metabolites could have an anesthetic dose on the brain. Many of the patients prescribed the higher dose 10% cream for have experienced some of these symptoms.
The other consideration has to do with the distribution of the dose. The progesterone cream enters from the skin into the fat. The progesterone is released from the fat into the blood stream in direct proportion to the concentration of the cream. The danger of using a higher dose cream is that there will not be a smooth release of the hormone into the blood stream over the 12 hour period.
Since progesterone has a relatively short half life of five minutes once it is in the blood, this will significantly limit its effectiveness and one will only receive partial benefits from the progesterone.
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