Estrogen is your hormone of memory so if you are near the time of menopause or post menopausal, very likely an estrogen deficiency is contributing to memory problems especially the brain fog that many women experience. Certainly we want to improve memory. There are many nutritional things that can help with memory, particular supplements such as Phosphatidylserine and Vinpocetine, keeping mentally active by reading, doing crosswords, doing puzzles and using the brain helps as well.

Yes.

Yes, bioidentical hormones are created in a laboratory. Most are derived from either soy or yams, now primarily yams in our area is the source of bioidentical hormones. Clearly this has to be processed and purified in a laboratory before it can be compounded as a prescription. So they are not derived from humans, they are derived from a plant source and they are purified in a laboratory prior to being compounded as a hormone to ensure quality and purity of the product.

The allergies are likely connected to several things that have gone awry in the body.  I would first consider multiple causes, primarily gut health.  It is amazing when the gut barrier breaks down the blood stream gets exposed to allergens in the gut, you can really create a lot of allergies, both to food and otherwise in the body. So by increasing gut health by first doing a nice healthy detoxification program with your anti-aging physician's assistance, there is also a wonderful book called Clean by Dr. Alejandro Junger, which describes a fantastic three week detox program, this may be sufficient to help cure your allergies. The bioidentical hormones can be helpful in just obtaining optimal health.  People do feel better.  I think it would depend on your other health issues whether it would stop your allergies or not because you would really have to treat the whole body and get everything in the best working order possible then the allergies usually decrease, but I do recommend:

1. Detoxification.
2. Improving gut health using supplementation such as probiotics, glutamine, etc., depending on your particular needs to help improve the integrity of the gut lining and then also the bioidentical hormone replacement to help balance any hormone deficiencies you may have.  
3. I would also look at your cortisol levels and treat that as necessary as well.