Parkinson's disease (PD) is an increasing threat to first-world nations as their population ages, with around one in 100 suffering from it by age 60. Incurable, with treatments that do little to delay disease progression, PD induces severe disability and even death in those afflicted. The search for preventative measures has revealed the widely used psychoactive stimulant caffeine, which competitively inhibits adenosine receptors to induce a wide variety of effects. The inhibition of inflammation and microglial cell activation to reduce reactive oxygen species (ROS)-induced cellular damage and the resultant mitochondrial dysfunction of the dopaminergic neurons appears to be the main pathway, inducing neuronal loss via the activation of the intrinsic pathway to apoptosis. Mouse models and human data reinforce that caffeine delays the onset of PD in a dose-dependent manner. Evidence suggests it is more beneficial in men than women and is not beneficial at all in women undergoing hormone replacement therapy (HRT). Additionally, some studies suggest that although caffeinated drinks such as cola and tea are beneficial, there may be other products in coffee that prevent the effect, though this requires further research. Although there is strong evidence that caffeine is neuroprotective, there is less evidence that it delays the onset of PD. Given the association with cardiovascular disease, it may be disadvantageous overall to the majority of the population to supplement caffeine, though still a beneficial preventative technique for individuals with a genetic predisposition to PD that may otherwise suffer early onset.