As people age, hormone levels naturally go down. It is part of the aging process. With our expanded life expectancy, using hormones during this later time of life, may become problematic.

There are hormone receptors on cells, and we know that in breast cancer patients, who have positive estrogen receptors, that estrogen is contraindicated.

For men with prostate cancer, hormone receptor blockers are used. Lupron is one such hormone reducing medication used for prostate cancer.

No one yet can say on a cellular level what is happening to people. So any small cancer not detected yet, has the potential for being stimulated by any hormone for which it has the corresponding receptor.

One can look this up on the net, and I am not going to do so today because I am too busy.

That being said, I still advocate that people proceed with caution about self medication with hormones or hormone stimulants.

As far as Vit B12 and D being able to reduce once fixed? Not necessarily so.

Whatever causes the B12 and D to get low in the first place has to be fixed...and finding that is still not an easy task, and perhaps that whole system is broken.

People with malabsorption issues (Crohn's or Celiac) or those with genetic errors in enzyme manufacture (MTHFR polymorphism) are not going to be able to go off the supplements they need. Some people lose the ability to make Vit D in the skin, and they will need supplements instead.

Dr. Sahelian is a good reference. He typically has studies on his site which are useful. However, I don't think the very newest dates for studies are updated often there.

As we age our mitochondria age as well. This is where the research is going. So interested people here can search the "mitochondria" papers to find more on this topic. Starting at Juvenon.com is a good beginning as Dr. Ames is a forerunner of this research.