Objective: Topical application of minoxidil has been adopted as an effective treatment for male and female pattern hair loss. While higher concentration formulas exhibit better efficacy, dissolving and stabilizing minoxidil is technically challenging. L-(+)-Tartaric Acid (LTA) is a colorless crystalline dicarboxylic acid found in plants and has been used as an additive in various hair care products to stabilize the biological functions of active ingredients. LTA has been added to minoxidil to maintain the quality of over-the-counter formula. To date, the influence of LTA on human Hair Follicle (HF) cells has not been sufficiently investigated. As the Dermal Papilla (DP) plays pivotal roles in the regulation of HF regeneration and the hair cycle, we aimed to elucidate the effects of LTA on human Dermal Papilla cells (hDPCs). Methods: hDPCs were first subject to cytotoxicity and alkaline phosphatase assay after treated LTA. Microarray comparison analysis was performed to elucidate LTA effects on global gene expression on LTA-treated and non-treated hDPCs. Subsequent real-time polymerase chain reaction analysis using multiple donor-derived hDPCs was done to further confirm LTA-induced hair growth genes up-regulation. Results: LTA exhibited no influence on hDPCs in a cytotoxicity assay. The activity of a representative hDPC marker enzyme, alkaline phosphatase, was not impaired by LTA in cultured hDPCs. Microarray comparison analysis of LTA-treated and non-treated hDPCs elucidated that LTA minimally affected the molecular signature of hDPCs but, intriguingly, up-regulated some hair growth-related genes. Subsequent real-time polymerase chain reaction analysis using multiple donor-derived hDPCs confirmed that LTA indeed increased the gene expression of activin A receptor type 2A (ACVR2A) and Insulin-like Growth Factor Binding Protein 5 (IGFBP5), while down-regulation of hair growth-related genes by LTA was inconsistent among hDPCs derived from respective donors. Conclusion: These results suggest that LTA minimally affects but potentially supports the biological characteristics of hDPCs. LTA may represent a useful additive to generate efficacious, high concentration formula of active reagents, represented by minoxidil.