There are literally thousands of papers/studies/trials on the subject some lots about athletic uses, lots about safety but some really interesting niche ones as well. Here are a few of the more recent ones that may be of interest, the cognitive effects and sleep related ones really interest me. iirc all these abstracts or conclusions are really good too so if you have faith in the sources, which I do, a deep dive is not a necessity.
www.nature.com
pmc.ncbi.nlm.nih.gov
Single dose creatine improves cognitive performance and induces changes in cerebral high energy phosphates during sleep deprivation - Scientific Reports
The inverse effects of creatine supplementation and sleep deprivation on high energy phosphates, neural creatine, and cognitive performances suggest that creatine is a suitable candidate for reducing the negative effects of sleep deprivation. With this, the main obstacle is the limited exogenous...
www.nature.com
“Heads Up” for Creatine Supplementation and its Potential Applications for Brain Health and Function - PMC
There is emerging interest regarding the potential beneficial effects of creatine supplementation on indices of brain health and function. Creatine supplementation can increase brain creatine stores, which may help explain some of the positive ...
pmc.ncbi.nlm.nih.gov