Great! So I'll live to 250?

(Fortune Magazine) -- How long would these drugs let us live?

One clue comes from studies on calorie restriction, or CR. If a drug that mimics CR's effects gave us the same life span boost that rats get from CR, our average life span might increase to about 110. (Life expectancy for U.S. males born in 2003 is 74.8, and it's 80.1 for U.S. females born that year.)

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Still, many experts believe that drugs are on the horizon which could extend average life span by perhaps five to ten years. That may seem unimpressive. But their boost to life expectancy would "far exceed" that from totally eliminating cancer, says S. Jay Olshansky, a University of Illinois expert on the demographics of aging. That's because the risk of many deadly diseases skyrockets as we age, so even if one were vanquished, the others would soon get us, limiting the gain in average life span.

In contrast, an anti-aging drug, almost by definition, would retard all major diseases of aging at once. Drugs that boost life span might also abbreviate late-life disability - we'd stay fairly vigorous until the very end. That sunny view is supported by the fact that very old animals on CR tend to be remarkably lively until shortly before they die. Surprisingly, good health is also often seen in people over 100, whose durability resembles that induced by CR.

When will these anti-aging meds arrive?

In 2005 the Rand Corp. consulted medical experts on this question and reported that they believe there's a 50 percent chance that anti-aging drugs will be available within 20 years. Some researchers on aging, such as Harvard's David Sinclair, believe that medicines like those will come along much sooner - perhaps within a decade.

The optimists cite the fact that researchers have discovered dozens of gene mutations over the past 15 years that slow aging in mice, fruit flies, roundworms and yeast cells. That has revealed many molecular targets in the body that might be tweaked by drugs to mimic the effects of such mutations.

Anything besides resveratrol on the horizon?

Several substances have shown tantalizing hints of anti-aging effects in animal and test-tube studies. A diabetes drug called metformin, for example, mimics many of the gene-activity changes that CR does. A metformin-like drug, called phenformin, appears to modestly extend rodent life span. Another compound, called 2DG, has been shown to mimic key effects of CR by blocking glucose metabolism.

But all these cause side effects that rule them out as anti-aging drugs. At this point resveratrol, or drugs that function like it, shows the most promise as an anti-aging medicine. Found to boost life span in diverse animal species, resveratrol appears to be safe to take at modest doses. But whether such doses extend human life span isn't known - and may never be because of the long clinical trials needed to prove it.

How large would the market be for these drugs?

Assume that the medicine is priced about the same as low-end cholesterol-lowering drugs - say, $1 a pill. That would make the yearly per capita cost $365. Now multiply that amount times the number of rapidly biodegrading baby-boomers, about 70 million. Ballpark answer: around $25 billion.

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