Sex and DNA may change how your body handles this supplement

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. individuals of both biological sexes, assigned as women or men at birth 2. age: ≥ 18 and ≤ 40 years 3. possesses the ability to understand the study purpose and design 4. contractually capable and provides signed informed consent form 5. in good general health or with mild and/or well-managed conditions such as allergies, asthma, hypertension or orthopedic diseases 6. taking no more than three chronic medications 7. individuals classified as either extensive metabolizers (EM) or poor metabolizers (PM) based on their CYP2D6 genotype: Extensive Metabolizers (EM): homozygous for CYP2D6 \*1,CYP2D6 \*2, CYP2D6 \*35, or heterozygous combination of any of these alleles Poor Metabolizers (PM): homozygous for CYP2D6 \*3, CYP2D6 \*4, CYP2D6 \*5, CYP2D6 \*6, or heterozygous combination of any of these alleles Exclusion Criteria: 1. BMI \> 30 kg/m2 and \< 18 kg/m2 2. body weight \< 48 kg 3. women: known pregnancy or lactation period; positive urine pregnancy test at screening or kinetic visit 4. men: hemoglobin \< 13 g/dl (8,07 mmol/l) women: hemoglobin \< 12 g/dl (7,45 mmol/l) 5. elevated liver function tests (1 or more of ALAT, ASAT, yGT, Bilirubin \> 2x ULN) 6. reduced renal function (eGFRMDRD \< 60 mL/min/1,7 m2) 7. QTcF \> 450 ms in screening ECG 8. current or recent psychiatric disorders requiring treatment including depression, bipolar disorder, schizophrenia, psychosis or severe anxiety disorders 9. drug dependency at the time of visit 10. use of recreational drugs more than twice a week 11. any known hypersensitivity or allergic reactions to yohimbine or caffeine 12. history of severe hypersensitivity reactions and/or anaphylaxis 13. poor venous conditions that make it impossible to place a peripheral venous catheter and regularly draw blood through it o) intake of drugs interfering with CYP2D6 and/or CYP1A2 during the past seven days p) intake of yohimbine within 48 hours and caffeine within 16 hours prior to study participation q) engagement in extreme physical activity within 48 hours prior to study participation