Beefy Bull, I haven't seen any research on that .. Usually the sperms themselves are quite vulnerable, so while you take DNP (and quite some time after, because it accumulates in your body), probably your sperm will be of low quality. DNP f*cks up your ATP-production and ATP (energy) is extremely important for sperm to propel itself. But the cells that produce sperm probably are not harmed, otherwise effects to male reproduction would be known.