Para-aminobenzoic acid (PABA) has historically been promoted in the supplement industry and alternative health circles as beneficial for hair health, especially for preventing or reversing graying hair. The basis for its use is largely anecdotal and stems from early 20th-century observations and some animal studies where PABA deficiency in certain animals led to changes in fur pigmentation. However, these findings have not been substantiated in robust human clinical trials. There is little to no reliable scientific evidence showing that PABA supplementation has a significant effect on hair growth, color, or overall hair health in humans. Mainstream medical and dermatological organizations do not recommend PABA for hair-related concerns. Thus, its use in this context is primarily traditional, rooted in historical usage rather than validated by contemporary scientific research. The overall evidence supporting PABA as an effective supplement for the hair body system rates as very weak (1 out of 5), reflecting its reliance on tradition and the lack of strong or consistent scientific support.