1,4-DMAA

1,4-Dimethylamylamine (1,4-DMAA), systematically named 5-methylhexan-2-amine, is a branched-chain aliphatic amine of the alkylamine stimulant class. It is a positional isomer of the better-characterized 1,3-dimethylamylamine (1,3-DMAA, methylhexanamine), differing in the placement of the methyl branch along the carbon backbone: in 1,3-DMAA the branch is at carbon 4 (producing 4-methylhexan-2-amine), whereas in 1,4-DMAA the branch is at carbon 5 (producing 5-methylhexan-2-amine). The compound has never been developed or marketed as a pharmaceutical agent, in contrast to 1,3-DMAA, which was introduced by Eli Lilly as an inhaled nasal decongestant (Forthane) in 1948 and voluntarily withdrawn in 1983. 1,4-DMAA came to regulatory and scientific attention through its identification in dietary supplements marketed for pre-workout stimulation and weight loss, where it was detected at doses of 21 to 94 mg per serving alongside other undeclared stimulants including 1,3-DMAA, octodrine, and 1,3-dimethylbutylamine, as reported by Cohen et al. (2018) in Clinical Toxicology. The compound has also been detected at trace concentrations (13 to 162 ng/g) in Pelargonium graveolens (geranium) plant material from the Changzhou region of China, as documented by Fleming et al. (2012), though these concentrations are insufficient to account for the milligram-scale quantities found in commercial supplement formulations. The pharmacology of 1,4-DMAA has not been independently characterized in published receptor-binding, transporter-interaction, or in vivo behavioral studies. Its mechanism of action is inferred by structural analogy to 1,3-DMAA and to the broader class of aliphatic alkylamine sympathomimetics. 1,3-DMAA has been characterized as an indirect sympathomimetic agent that competitively inhibits dopamine uptake at the human dopamine transporter (DAT) with an IC50 of approximately 29.4 micromolar (roughly 60-fold less potent than amphetamine) and that induces DAT endocytosis through cocaine- and protein kinase A-sensitive mechanisms, as reported by Bhatt et al. (2023). By structural analogy, 1,4-DMAA is presumed to function as a catecholamine releasing agent with sympathomimetic properties, producing vasoconstriction, elevated blood pressure, increased heart rate, and central nervous system stimulation, though the potency and selectivity of these effects relative to 1,3-DMAA remain unquantified. No human pharmacokinetic data specific to 1,4-DMAA have been published. The pharmacokinetic profile of 1,3-DMAA, characterized by Bloomer et al. (2013) in seven healthy men receiving a single 25 mg oral dose, provides the closest available analog: peak plasma concentration of approximately 70 ng/mL at 3.6 hours, terminal elimination half-life of 8.5 hours, oral clearance of 20 L/hr, and volume of distribution of 236 L. Whether these parameters translate to the 1,4-isomer is unknown. The safety of 1,4-DMAA in humans is unknown. The compound has not been studied in controlled clinical trials at any dose. Cardiovascular adverse events (hypertension, tachycardia, and theoretical risk of hemorrhagic stroke and sudden cardiac death) are inferred from the pharmacology of structurally related sympathomimetic amines and from case reports associated with 1,3-DMAA-containing products. The United States Food and Drug Administration considers 1,4-DMAA to be an illegal ingredient in dietary supplements and has stated that products containing it should not be consumed. The World Anti-Doping Agency includes 1,4-dimethylamylamine on the Prohibited List under category S6 (stimulants, prohibited in competition). This monograph reviews the chemistry, structural classification, inferred mechanism of action, pharmacokinetic analogy data, detection in plant material and supplements, regulatory status, adverse-event signal, sourcing and handling considerations, and a comparative assessment of five structurally or functionally related alkylamine stimulants against 1,4-DMAA on five competency standards: novelty, effect size, side-effect profile, regulatory status, and overall validation.