While too much caffeine can cause negative side effects such as anxiety or a fast heartbeat, there is plenty of evidence in the scientific literature about caffeine, its health benefits, and its potential as a microdosing agent.
In addition to increasing energy and improving cognition, there are also some studies that indicate that this can affect inflammatory conditions and autoimmunity. Other literature suggests that natural sources of caffeine, such as coffee, can help prevent prediabetes and type 2 diabetes.
Caffeine has also been researched as a performance enhancer for athletes and the military since the 1970s, but often in moderate to high doses. However, what we're finding now is that low doses can be safer and better for the body: they can help improve alertness, mood, and awareness during and after exercise, but with few (if any) side effects. A recent review found that low caffeine doses as low as 3 mg could be as effective as higher doses.
In addition, Harvard scientists conducted a randomized, double-blind, placebo-controlled study in which 16 male subjects microdosed and sequestered caffeine for 29 days. They were also deprived of time information so that they could simulate the extended vigilance that doctors, military personnel and first aiders often experience. The researchers found that those who took the low-dose caffeine supplement performed better on cognitive tests and had fewer accidental sleep disorders. The results suggest that microdosing caffeine can be especially helpful when a person has to wait for the opportunity to have a good night's restful sleep (think of key staff).