Just so that we make sure we cover the basic possibilities first, lets make sure that:
1) They're not expired
2)They're in a higher dose then, say 8mg
3) You don't drink caffeine all day long as it is. Meaning a 200mg caffeine pill wont do as much for you.
Extracts of Ephedra have been used as a starting material for the clandestine preparation of methamphetamine. Suggesting that Ephedra can be a precursor to methamphetamine!
Methamphetamine = Ecstasy (the drug)
Some effects associated with "Meth", and therefore, possibly Ephedra are:
Loss of appetite,
Loss of concentration,
Tension and trembling of the eyes,
Lack of initiative and motivation,
Grinding of teeth,
Anxiety and confusion,
Some evidence suggests that many modern so-called natural products are actually "spiked" with synthetic ephedrine (up to 8%) to enhance their immediate effect.
There is also evidence to support these being some of the reasons ephedra was banned in the first place.