The quality of supplements containing SAMe, used to treat a range of conditions including joint pain and depression, has improved considerably over the last few years but there are still some products on the market which mislead consumers.
ConsumerLab.com, the US organisation which regularly tests a wide range of supplements, said that its 2003 analysis of SAMe (S-adenosyl-methionine) supplements showed that manufacturers had made major improvements since its last test in 2000, when nearly half of the SAMe products it tested contained less ingredient than claimed.
Only one of eight products failed to meet its label claim in the latest test, the organisation said, containing just 30 per cent of the claimed amount, but it was also among the most expensive - costing $2.93 per day compared to the average price of $1.45 among the other products.
The SAMe test results mirrored those of its earlier analysis of another supplement also used to treat osteoarthritis - chondroitin. Earlier this month, ConsuemrLab.com said that its tests had shown that chondroitin supplements had also improved in quality, although one product that cost about twice as much as others contained only 18 per cent of the ingredient.
Tod Cooperman, ConsumerLab.com's president, said that the results showed that a high price means did not necessarily mean high quality. "We have seen more problems over the years among unusually high priced products than among low priced products. Perhaps the thinking of some manufacturers is 'If you are going to cheat, cheat big.' "
Cooperman said that quantifying SAMe was a difficult task, as the ingredient can break down under certain circumstances, resulting in the disparity between the quantity on the label and the actual content. He added that a stabilizing molecule is always added to SAMe products and that this also often made it unclear as to the true weight of active SAMe, because the inactive stabilizer could be included in the labeled amount.
Among the 11 products tested by ConsumerLab.com were Nature Made SAMe, Puritan's Pride Inspired By Nature SAMe and Vitamin World SAMe - all of which were approved by the company.
SAMe supplements first became popular in the US in 1999 and accounted for $77 million in sales last year, ConsumerLab.com said.