Casein makes up 80% of milk protein (whey is the other 20%) and is the "slow protein" — it forms a gel (clot) in the stomach that digests over 5-7 hours vs whey's 1-2 hours. Our research shows this sustained amino acid delivery makes casein SUPERIOR to whey for anti-catabolic (muscle preservation) purposes but INFERIOR for acute muscle protein synthesis stimulation. The landmark Boirie 1997 study showed casein suppressed whole-body protein breakdown by 34% while whey stimulated synthesis by 68% — they're complementary, not competing. Micellar casein is the intact native form; casein hydrolysate (PeptoPro®) digests fast like whey, defeating the purpose.
Micellar casein's unique property is pH-dependent gelation: at stomach pH (1.5-4), casein micelles aggregate into a semi-solid clot (the same chemistry that makes cheese). This clot digests slowly via pepsin, releasing amino acids over 5-7 hours. The sustained aminoacidemia maintains elevated blood leucine above the muscle protein synthesis threshold for much longer than whey (which spikes and crashes in 1-2 hours). For overnight recovery: pre-sleep casein provides amino acids throughout the 7-8 hour fasting period of sleep, preventing the catabolic state that occurs when blood amino acids drop below the synthesis threshold.
Based on independent third-party laboratory analysis
Category pass rate: ~75% pass rate for protein content. Heavy metal contamination is the bigger concern — 84% contain detectable arsenic, lead, or cadmium.
Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated:
Not medical advice. Based on published clinical research and systematic reviews.