Misuse of (±)‐threo‐methylphenidate (methyl‐2‐phenyl‐2‐(piperidin‐2‐yl)acetate; Ritalin®; MPH) has long been acknowledged, but the appearance of MPH analogs in the form of ‘research chemicals’ has only emerged in more recent years. 4‐Fluoromethylphenidate (4F‐MPH) is one of these recent examples. This study presents the identification and analytical characterization of two powdered 4F‐MPH products that were obtained from an online vendor in 2015. Interestingly, the products appeared to have originated from two distinct batches given that one product consisted of (±)‐threo‐4F‐MPH isomers whereas the second sample consisted of a mixture of (±)‐threo and (±)‐erythro 4F‐MPH. Monoamine transporter studies using rat brain synaptosomes revealed that the biological activity of the 4F‐MPH mixture resided with the (±)‐threo and not the (±)‐erythro isomers based on higher potencies determined for blockage of dopamine uptake (IC 50 4F‐MPH mixture = 66 nM vs. IC 50 (±)‐threo = 61 nM vs. IC 50 (±)‐erythro = 8,528 nM) and norepinephrine uptake (IC 50 4F‐MPH mixture = 45 nM vs. (±)‐threo = 31 nM vs. IC 50 (±)‐erythro = 3,779 nM). In comparison, MPH was three times less potent than (±)‐threo‐4F‐MPH at the dopamine transporter (IC 50 = 131 nM) and around 2.5 times less potent at the norepinephrine transporter (IC 50 = 83 nM). Both substances were catecholamine selective with IC 50 values of 8,805 nM and >10,000 nM for (±)‐threo‐4F‐MPH and MPH at the serotonin transporter. These findings suggest that the psychostimulant properties of (±)‐threo‐4F‐MPH might be more potent in humans than MPH. Copyright © 2017 John Wiley & Sons, Ltd.