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DHEA and testosterone - fountains of youth or a lot of hype?
(February 2007)

At present, about 12 percent of the US population (37 million people) are over age 65, 4.5 million over age 85.  By the year 2050, about 20 percent of our population (80 million) will be over age 65 and 20 million will be over age 85.  The rapid growth of the older (as well as the very old) population in the United States has spawned anti-aging organizations, programs, and entrepreneurs.  They advocate all sorts of hormones, herbs, minerals, neutraceuticals, pharmacologic agents, and lifestyle changes, all in the hope of “rejuvenation” and increasing longevity with a good quality of life.  These efforts at “rejuvenation” have created often acerbic controversy that is focused on evidence or lack of evidence about whether these remedies actually work.

Three of the most popular of the drugs are hormones - growth hormone, dehydroepiandrosterone (DHEA) and testosterone.  In each case, blood levels fall as adults grow older.  Growth hormone levels fall about 12 percent per decade after middle age.  DHEA starts to decline after age 30, and a large proportion of older men have blood testosterone levels that are far lower than younger men.  There is then a rationale for giving these hormones and some supporting evidence in animal studies and in the case of testosterone in humans who have been reported to alter their appearance, losing fat, increasing muscle mass, and looking younger.  As usual, early reports are enthusiastic, later reports often are far less enthusiastic.

The New England Journal of Medicine of October 19, 2006 includes a carefully designed study from the Mayo Clinic in Rochester, Minnesota.  Twenty-seven women, average age 68 years, were given DHEA; 27 men, average age 66 years, were given testosterone, and 29 men, average age 68 years, were given DHEA.  In each case, there were appropriate controls given inactive placebos.  DHEA dose was 50 to 75 milligrams daily; testosterone, 5 milligrams a day, was given by a skin patch.  Medication was continued for two years.

In the DHEA treated, there was a slight increase in fat-free mass and a slight decrease in body fat.  Those men given testosterone had a substantial increase in fat-free mass and a lesser decrease in body fat, but no change in the thigh muscle area.  However, there was no increase in muscle strength with either DHEA or testosterone.  In both treatment groups, there was some increase in bone strength at one or two of the five sites measured.

There was no improvement in either physical or mental quality of life, and no change in physical fitness or performance.  There was no evidence the hormones caused harm.

The authors conclude “ taken together, our data provide no evidence that either DHEA or low dose testosterone is an effective anti-aging hormone supplement and argue strongly against the use of these agents for the purpose”.

Commentary:  This study has limitations; in particular, the number of participants is fairly small and the dose of testosterone will be considered by some to be too low.  Additionally, the two-year time period may be too short to detect adverse effects.  But, these are small criticisms when weighed against the conclusion that DHEA and testosterone showed no important benefits and no significant rejuvenation.  The improvements in bone strength are small and unlikely to reduce fracture rates.

A very good accompanying editorial summarizes the available data and concludes the evidence supports the conclusions summarized above.  The editorial also points out that commercially available DHEA preparations range in actual DHEA content from zero to 50 percent more than indicated on the package.

In sum, testosterone may make some men look better (less body fat) or, as in a French study, may increase libido in some women, but the available studies do not provide any justification for giving either DHEA or testosterone to aging people even if blood levels of the hormones are low.  And, we still do not have adequate data on long-term adverse effects, especially if doses of testosterone administered are higher than those used here.

These hormones are not the Fountain of Youth.

Nair, K.S., et al.  DHEA in elderly women and DHEA or testosterone in elderly men.

And

Stewart, P.M.  Aging and the Fountain-of-Youth hormones.

The New England Journal of Medicine.  Vol 355 (October 19) Pgs 1647-1659, 1724-1726.  2006.

There are still some unsettled areas.  Testosterone may not be warranted in older people in general, but what about men whose blood levels are very low (not just low, but very low)?

DHEA may not appear to be effective, but why is it that greater longevity in calorically restricted monkeys and in longer living people (at least in one study) are associated with higher DHEA levels?

There is a lot we do not know that needs to be investigated, but that is no reason for irresponsible entrepreneurs to be hawking these hormones or even for responsible anti-aging physicians to be prescribing these hormones on the basis of inadequate evidence.