Stellar evolution is sensitive to the existence of low-mass particles with very weak couplings to matter. They can be abundantly produced in stellar interiors, escape without further interaction, and thus contribute directly to the stellar energy losses. Neutrinos are a prime example, but hypothetical particles predicted in extensions of the standard model of particle physics could also play a role. The comparison of detailed astronomical observations with detailed stellar evolution calculations has been widely used to constrain the existence of axions, millicharged particles, Kaluza-Klein gravitons and so forth, and to test novel couplings of neutrinos such as dipole moments. Our goal is to re-examine the impact of novel low-mass particles in the evolution of globular cluster stars in light of the most recent astronomical and physical data.