Díaz Lab Testing Store › Insulin + C-Peptide | Insulin + C-Peptide | $87.00 Measures insulin production and resistance — the root cause marker behind weight gain, fatigue, and Type 2 diabetes. Add To Cart Added! Measures insulin production and resistance — the root cause marker behind weight gain, fatigue, and Type 2 diabetes. Add-on: Integrative-Functional Lab Interpretation Report with Recommendations by Adalys Díaz $77.00 Add Added!