ROBERT SIEGEL, HOST:
Back to Earth now and some science that might hit a bit closer to home. We're talking about a substance used for everything from weight loss to body building. It's called DMAA, and it's especially popular as an ingredient in dietary supplements. Weight lifters and others take them to get a boost before working out. As NPR's Rob Stein reports, critics say it's a dangerous stimulant that should be pulled from the market.
ROB STEIN, BYLINE: Richard Kessinger loves to hit the gym, but some days, he needs a little something to get him pumped up for his weight lifting routine.
RICHARD KESSINGER: You might be a little bit sore. You might be tired. You might had too many beers the day before. You might start putting up a set and you get a few reps in and you're like, I'm not feeling this. I can't keep going.
STEIN: So Kessinger, who's 23 and lives in Arlington, Virginia, swallows some DMAA. It's also called geranium extract because supposedly it can be found in geranium plants in China. Kessinger says it gives him that little extra burst of intensity that he needs.
KESSINGER: I just use it as a stimulant, get a little extra energy boost, a little focus boost before my workout. It just gives you a little extra kick.
STEIN: Sometimes, Kessinger takes it just to go to work when he's feeling, you know, a little logy.
KESSINGER: If I have a day that's dragging at the office, it creates sort of a little like elevated mood, sort of happy feeling.
STEIN: Kessinger is far from alone. The National Business Journal says Americans spent more than $100 million on products containing DMAA in 2011.
PIETER COHEN: This is the most dangerous ingredient sold today in supplements in the United States.
STEIN: That's Pieter Cohen of Harvard Medical School. He says DMAA is a potent stimulant. It drives up heart rate and blood pressure, and that's why it can cause so many problems.
COHEN: The common ones would be anxiety, panic attack, dehydration, and the life-threatening ones would be bleeding strokes and death, sudden cardiac death.
STEIN: The Food and Drug Administration has gotten dozens of reports of complications among people using DMAA, including at least two deaths. The military barred base stores from selling DMAA supplements after two soldiers died while taking them. It was recently linked to the death of a British marathon runner. Cohen and others even question whether DMAA should be considered a natural product.
COHEN: There's a few questionable studies that found trace amounts of this in one species of plant from China, and there's over half a dozen meticulously done academic studies that studied the same plant and found no DMAA.
STEIN: Companies selling DMAA products and some scientists dispute all this. Peter Hutt's a lawyer for USP Labs in Dallas. USP makes Jack3D, the most popular DMAA supplement. Its nickname is jacked. Hutt says there's plenty of evidence that DMAA is found naturally in some Chinese geraniums and that it is safe when used properly.
PETER HUTT: Among the dietary ingredients with which I'm familiar, this is probably the single most studied. It has approximately the same stimulant capacity as two cups of coffee.
STEIN: Hutt says the only time DMAA is a problem is when users take too much, mix it with alcohol and drugs or use it under extreme conditions.
HUTT: If someone went out, as some people have, in 102- to 105-degree temperature and conducted strenuous stress testing for hours and if they were overweight and took more of the product than labeled, then, yes, there have been problems.
STEIN: But Cohen, he's the critic from Harvard, says supplement companies should have to prove their ingredients are safe before they're allowed to be sold.
COHEN: DMAA is really a poster child for why the laws governing supplements aren't working.
STEIN: He wants the FDA to pull DMAA off the market. Officials at the FDA, like Daniel Fabricant, say the agency has been warning companies about DMAA, about its safety and whether it's really even an herbal remedy. It looks suspiciously like a drug once marketed as a decongestant.
DANIEL FABRICANT: This is something that someone just repurposed an old drug and felt like they could market it and sell it as a dietary supplement. That should be concerning to everybody.
STEIN: For his part, Kessinger says he thinks DMAA is fine for people like him, healthy people who use it carefully.
KESSINGER: I don't think it should be illegal for me to buy. I think that an educated person can use it safely and avoid having any issues with it.
STEIN: Some companies have started taking DMAA out of their supplements, and the FDA says it could take more aggressive steps if others keep selling it. But for now, products containing DMAA are still easy to find in vitamin shops and all over the Internet. Rob Stein, NPR News.
SIEGEL: I'm Robert Siegel, and I'm going to be gone for a few weeks and back when the Ides of March are safely past. Melissa and Audie aren't going anywhere. This is ALL THINGS CONSIDERED from NPR News.