The primordial helium-3 abundance, inferred from Big Bang Nucleosynthesis calculations and measured from the intergalactic medium, exhibits constraints that are difficult to satisfy simultaneously with other light element abundances (deuterium, helium-4, and lithium-7) in the standard Lambda-CDM nucleosynthesis framework. The helium-3 abundance appears to have lower production rates or different evolution patterns than expected, suggesting either underestimated stellar processing of helium-3, unknown nuclear physics, or non-standard early-universe nucleosynthesis conditions (Cyburt et al. 2016; Iocco et al. 2009).