Answer: Hello Account R, thank you for your question. ProMix uses cold micro-filtration rather than acid or ion exchange. The whey is passed through cool pipes and filtered by progressively finer mesh filters so only the protein molecules and smaller sub fractions like (e.g. immunoglobulins...) pass through the filter but larger molecules (e.g. lactose) are filtered out. Please email us if you have any additional questions. Thank you!