Aim of the study is to investigate the postprandial response on blood glucose, insulin, C-peptide, incretin response and gastric emptying after intake of collagen hydrolysate compared to placebo in normoglycemic and in prediabetic participants. This will be investigated in a cross-over randomized double-blind placebo controlled study design.

In an exploratory part II, timing of intake of collagen hydrolysate in relation to the mixed meal will be investigated in a subgroup of 50% of the participants.

Inclusion Criteria:

• Prediabetic subjects: Male and female subjects with prediabetic HbA1c values between 5.7% and 6.4% and/or fasting glucose ≥ 100 mg/dL and ≤ 125 mg/dL (in venous plasma) (twice confirmed at two independent days if HbA1c is < 5.7%) or Healthy normoglycemic subjects: fasting glucose <100 mg/dL and HbA1c is < 5.7%
• Age: 18-70 years
• Body mass index 19-35 kg/m2
• Current Non-smoker
• Signed informed consent form
• No changes in food habits or physical activity 3 months prior to screening and during the study
• If applicable, stable intake of chronic medication of at least 4 weeks

Exclusion Criteria:

• Subjects with diagnosed Type 2 Diabetes mellitus with medical treatment
• Presence of disease or drug(s) influencing digestion (incl. recent intake of antibiotics) and absorption of nutrients
• Intake of medications known to affect glucose tolerance, e.g., diabetic medication, SGLT-2 inhibitors, GLP-1 receptor agonists, steroids, protease inhibitors or antipsychotics
• Chronic intake of substances affecting blood coagulation (e.g. acetylic acid (100 mg as standard prophylactic treatment allowed when dose is stable 1 month prior to screening), anticoagulants, diuretics, thiazides (diuretics and thiazides allowed e.g. for hypertension treatment when dose is stable 1 month prior to screening), which in the Investigator's opinion would impact patient safety
• Severe liver or renal disease or laboratory evidence of hepatic dysfunction (i.e. alkaline phosphatase, ALT, AST >3 x ULN)
• Known inflammatory or malignant gastrointestinal diseases (i.e. colitis ulcerosa, Morbus Crohn, celiac disease, malignant diseases e.g. colon-cancer, rectum cancer, pancreatitis)
• Subjects who use an implanted or portable electro-mechanical medical device such as a cardiac pacemaker or infusion pump.
• Planned MRI during or 4 weeks after the study.
• Subjects overweighed with abdominal diameter >140 cm
• Clinically relevant findings as established by medical history, physical examination, clinical laboratory and/or vital signs
• Major medical or surgical event requiring hospitalization within the previous 3 months
• Intake of food supplements known to affect glucose tolerance, e.g., cinnamon capsules, conjugated linoleic acids
• Drug-, alcohol- and medication abuses
• Pregnant or breast-feeding women
• Weight loss intervention or recent body weight change >5 kg during the last 3 months
• Blood donation within 4 weeks prior to Screeningor plan to donate blood during the study
• Anticipating any planned changes in lifestyle for the duration of the study
• Participation in another clinical intervention study within the last 4 weeks and concurrent participation in another intervention clinical study
• Subjects considered inappropriate for the study by investigators, including subjects who are unable or unwilling to show compliance with the protocol