A number of articles on DHEA have surfaced in the wake of a recent study:

The findings suggest that DHEA replacement therapies could reverse some of the hormonal and metabolic changes that come with aging and cause abdominal fat to accumulate more easily.

...

Since levels of DHEA decline with age, supplementing to maintain youthful levels is thought by some to be a valuable antiaging strategy. DHEA is currently widely available as a dietary supplement, after it was banned by the FDA in 1985 due to a lack of scientific proof that it was safe for over-the-counter sale as a drug.

There has been debate over the value of DHEA supplementation, and some think that it may be harmful. DHEA eventually converts into testosterone and estrogen, for example, so might increase the risk of prostate tumors in men and ovarian cancer and heart disease in women.

While the new study suggests that DHEA supplementation could have valuable therapeutic benefits, the researchers involved admit that it was run on too small a cross-section of participants to be considered anything more than preliminary. They are currently planning more long-term, large-scale studies to determine possible negative side-effects.

I think the Wikipedia entry cuts more directly to the chase, however:

The significance of the hormone in health and disease is not fully established. It is postulated that substitution of it can be beneficial in a number of disorders

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However, there is too little scientific proof to advocate the use DHEA outside specialist centres under careful observation of experts in the field of endocrinology.

DHEA has long been a favorite of the old school healthy life extension community (as for other line items, in the absence of what I would consider sufficient scientific backing for commonplace use). I think that the diversity of studies and results for varied hormone treatments indicate that we don't fully understand the mechanisms and consequences of such treatments, and that results vary widely between people.

Hormone-related treatments like this seem to be a case of pulling the unmarked big red lever on the side of the complex machine. We need more research - but I suspect there are better areas on which to focus resources than homone-related supplements.