Inclusion Criteria:  Informed Consent as documented by signature Age between 18 and 74 years old One or more kidney stone event(s) in the past Any past kidney stone containing ≥ 80 % of calcium or ≥ 80 % of uric acid HbA1c < 6.5 %  Exclusion Criteria:  Patients with secondary causes of recurrent nephrolithiasis: Severe eating disorders (anorexia or bulimia) Chronic bowel disease, past intestinal or bariatric surgery Sarcoidosis Primary hyperparathyroidism Complete distal tubular acidosis Patients with the following medications: Anti-diabetic treatment (insulin and non-insulin agents) Patients not able or not willing to stop the following medication during the period of participation in the trial (including a time window of 4 weeks wash out prior to randomization): Diuretics (thiazide and loop diuretics) Carbonic anhydrase inhibitors (including topiramate) Xanthine oxidase inhibitors Alkali, including potassium citrate or sodium bicarbonate Treatment with 1,25-OH Vitamin D (calcitriol) Calcium supplementation Bisphosphonates, Denosumab, Teriparatide Glucocorticoids Obstructive uropathy, if not treated successfully Genito-urinary infection, if not treated successfully Chronic kidney disease (defined as CKD-EPI eGFR < 60 mL/min per 1.73 m2 body surface area) Kidney transplant Pregnant and lactating women [urine pregnancy test to be performed for women of childbearing potential (defined as women who are not surgically sterilized/ hysterectomized, and/ or who are postmenopausal for less than 12 months)] or women of childbearing potential that refuse to use an effective contraceptive method (birth control pill or IUD). Inability to understand and follow the protocol Known allergy to the study drug Participation in another interventional clinical trial within 4 weeks prior to baseline and during the current trial