There are any number of herbal energy boosters. Some are safer than others and much depends on your present health.
Yohimbe Bark is known to raise blood pressure and increase blood flow -- these may not be a good idea for many people. There are also a good many contraindications.
Remember, just because it is herbal doesn't mean it is good for you. If you really want an herbal solution to energy drops, visit with a quality herbalist.
Personally, I've been known to use herbals for that very reason. And they do work if you use the right compositions.
Trial and error is a very bad way to learn about herbal health products...