The study aims to determine the effect size of magnesium and bicarbonate supplementation as a basis for future randomized controlled trials aiming at the T50-guided improvement of hard clinical endpoints in dialysis patients.

Inclusion Criteria:

• Male or female hemodialysis patients ≥ 18 years of age
• Negative pregnancy test of female patients in child-bearing age
• The patients have to be able to understand the character and the individual impact of the clinical study and they have to give written informed consent to participate in the study
• Start of chronic hemodialysis treatment ≥ 3 months ago
• HCO3- in venous plasma ≤23 mmol/L before the start of the last dialysis of the week
• Magnesium in venous plasma ≤ 1.45 mmol/L before the start of the first dialysis of the week
• T50 ≥ 200 minutes.

Exclusion Criteria:

• Pregnant or lactating subjects. A blood pregnancy test will be performed at the screening visit in female patients of childbearing age.
• History of alcohol abuse, illicit drug use, significant mental illness, physical dependence to any opioid, or any history of drug abuse or addiction within 12 months of study enrolment