Overexpression of telomerase has been demonstrated to substantially extend the lifespan of mice. However, this treatment has a negative side, namely the increase of cancer risk. Most components of the telomerase holoenzyme complex possess high basic amino acid content, potentially attracting anions and enhancing the formation of mutagenic and carcinogenic HCl. Weak organic acids antagonize strong acids, and thus can raise cellular pH and modify the microenvironment. R-loops are hybrid DNA and RNA structures, and trigger DNA replication stress and genome instability. RNA has one additional hydroxyl oxygen atom on ribose compared with DNA, and single stranded DNA harbors bases free of hydrogen bonding. These two factors can enhance the buildup of protons via hydrogen bonding and the local formation of HCl. Strong acids generated can augment DNA mutagenesis, and enhance DNA excision, repair and formation of double stranded breaks. Neoplasm must be addressed before lifespan extension remedies via telomerase are ready for use.