There is no safe and effective ephedra dosage. As a matter of fact, the FDA has banned ephedra because it proved that ephedra was an unsafe diet pill that could cause very dangerous side effects (even when used in low doses and for short periods of time). If you decide to take ephedra, you are putting your health at risk by gambling with a product that is being made illegally by an untrustworthy manufacturer.
A safe and effective ephedra (ma huang) dosage cannot be recommended. The FDA banned ephedra in 2004, and that ban is still in place. The FDA does not have any authority to ban a supplement unless it can prove that the supplement is unsafe -- it clearly and convincingly showed that ephedra was indeed unsafe. You may hear that ephedra is only dangerous when used for a long period of time or in high doses. However, there have been reports of dangerous side effects in people taking low ephedra doses for a short period of time.
If you decide to use an ephedra supplement, it is important to understand that what you see on the label may not reflect what is in the bottle. For example, some herbal supplements have been found to be contaminated with heavy metals or prescription drugs, and some have been found to have much more or much less of the featured ingredient than their label states. Usually, to avoid such problems, it is recommended to make sure the maker of your herbal supplement is a trusted and reputable manufacturer. However, because ephedra has been banned, no manufacturer that makes ephedra should be considered trustworthy and reputable.
By taking ephedra, you are gambling with your health in several different ways. You are gambling that you will be lucky enough not to experience any dangerous ephedra side effects. You are also gambling with your health by taking a product made by a manufacturer that is not trustworthy and is operating illegally. Even if a safe and effective ephedra dosage could be recommended, you would have no way of knowing if you were actually getting that dose (because the ephedra manufacturers cannot be trusted).