2. Academic Validation
  3. In vitro inhibition of monoamine transport by amphetamine-like pre-workout supplement ingredients

In vitro inhibition of monoamine transport by amphetamine-like pre-workout supplement ingredients

  • Toxicology. 2026 Jun:523:154442. doi: 10.1016/j.tox.2026.154442.
Nicole E T Pinckaers 1,  Paulina D Sawicka 2,  J Pepijn Wopken 2,  W Matthijs Blankesteijn 3,  Frederik-Jan van Schooten 4,  Antoon Opperhuizen 5,  Misha Vrolijk 4,  Remco H S Westerink 2
Affiliations

Affiliations

  • 1 Department of Pharmacology and Toxicology, Maastricht University, PO Box 616, Maastricht 6200 MD, the Netherlands; Research Institute of Nutrition and Translational Research in Metabolism (NUTRIM)sup, Maastricht University, PO Box 616, Maastricht 6200 MD, the Netherlands. Electronic address: [email protected].
  • 2 Neurotoxicology Research Group, Institute for Risk Assessment Sciences, Faculty of Veterinary Medicine, Utrecht University, PO Box 80176, Utrecht 3508 TD, the Netherlands.
  • 3 Department of Pharmacology and Toxicology, Maastricht University, PO Box 616, Maastricht 6200 MD, the Netherlands; Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, PO Box 616, Maastricht 6200 MD, the Netherlands.
  • 4 Department of Pharmacology and Toxicology, Maastricht University, PO Box 616, Maastricht 6200 MD, the Netherlands; Research Institute of Nutrition and Translational Research in Metabolism (NUTRIM)sup, Maastricht University, PO Box 616, Maastricht 6200 MD, the Netherlands.
  • 5 Department of Pharmacology and Toxicology, Maastricht University, PO Box 616, Maastricht 6200 MD, the Netherlands; Office for Risk Assessment and Research, Netherlands Food and Consumer Product Safety Authority (NVWA), PO Box 43006, Utrecht 3540 AA, the Netherlands.
PMID: 41796714 DOI: 10.1016/j.tox.2026.154442
Abstract

Phenethylamine (PEA) and alkylamine (AA) analogues are a prominent group of pre-workout food supplement ingredients. They are structurally related to the stimulant amphetamine and to the endogenous catecholamines noradrenaline and dopamine, implying potential cardiovascular and psychological effects. This study systematically investigated the inhibitory potential of 12 PEAs and 4 AAs identified in pre-workout supplements on the human Dopamine Transporter (hDAT), human noradrenaline transporter (hNET) and human Serotonin Transporter (hSERT) that are stably overexpressed in HEK 293 cells. All PEAs and AAs tested, except DMAE, inhibited substrate uptake by one or more monoamine transporters. Overall, the substances displayed the highest potency and efficacy at hNET, followed by hDAT and with considerably weaker effects on hSERT. At hNET, potency values (IC50) ranged from 0.5 µM to 123 µM, with maximal inhibition (Emax) ranging from -59.2% to -120%. Inhibition of substrate uptake by hDAT occurred with IC50 values between 4.0 and 95.8 µM and Emax values between -66.8% and -135%. For hSERT 50% inhibition was observed at concentrations ranging from 2.6 µM to 131 µM, with maximal effect between 85.3% and -64.8%. These findings indicate a potential for sympathetic activation and behavioral rewarding and reinforcing effects. Notably, the in vitro potency and efficacy of several PEAs and AAs were comparable to those of the well-known illicit stimulants amphetamine and cocaine. Together, these findings highlight the urgent need to further characterize pharmacokinetic and pharmacodynamic properties of these pre-workout supplement ingredients to support robust risk assessment and informed regulatory decision-making regarding the safety of pre-workout supplement ingredients.

Keywords

Alkylamines; Dopamine; Food supplements; Monoamine transporters; Noradrenaline; Phenethylamines; Serotonin.

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