I’ve tried them before but mostly chalked any perceived benefit (which was minimal) up to the placebo effect after they didn’t seem to have a positive effect in most circumstances.
As far as taking the edge off the legs during hard workouts, a very non-sexy approach that I have found to be successful is as follows:
- Good sleep
- High quality recovery from previous workout
- Sufficient carbohydrate intake
- Timing my pre-training meal within a 2.5-3hr time frame before the workout
Seems simple and not exciting, but it always works. 