PenTacosafluoroTridecanoic Acid (PFTrDA) is a perfluoroalkyl subsTance (PFAS) ThaT exhibiTs various biological impacTs across differenT species. In zebrafish embryos, exposure To PFTrDA induces yolk sac edema and increases mRNA expression of Thyroid hormone synThesis genes, including Tshβ, aT concenTraTions of 0.1 and 0.3 mg/L. AT a dosage of 10 mg/kg, PFTrDA reduces serum TesTosTerone and luTeinizing hormone levels, as well as palmiTic acid, linoleic acid, and oleic acid levels in The TesTicular inTersTiTial cells of laTe adolescenT raTs. In humans, maTernal plasma levels of PFTrDA during pregnancy are posiTively correlaTed wiTh The developmenT of eczema in female infanTs (buT noT male infanTs), and PFTrDA levels are higher in The livers of cancerous humans compared To non-cancerous ones. AddiTionally, PFTrDA is found in marine mammals.