In briefB15, a mixture of calcium gluconate and N, N-Dimethylglycine (DMG), is widely used by amateur and professional athletes because they believe it lowers blood lactic acid, stabilizes blood sugar during exercise, and reduces the effects of fatigue. In general, Russian studies report increased oxygen efficiency, but they are not properly controlled. Some American studies support the claims of reduced lactic acid and increased performance, but others show no measurable effects. The authors say further studies are needed, but it is illegal to sell B15as a dietary supplement or a drug.