Casein Protein
Also known as: micellar casein, sodium caseinate, calcium caseinate, milk protein, beta-casein, slow-release protein
Effective Dosage
25-50 g daily based on study doses
What the Science Says
Casein is the primary protein found in cow's milk, making up about 80% of milk's protein content. It digests slowly, releasing amino acids steadily over several hours, which makes it popular as a pre-sleep protein to support overnight muscle recovery. Research suggests milk protein supplementation (including casein) can modestly reduce total cholesterol, triglycerides, and systolic blood pressure, and pre-sleep casein intake combined with probiotics may improve anaerobic power and lower-body strength in athletes.
What It Doesn't Do
Not a magic muscle builder — results in athletic studies are modest and often require combining it with other supplements like probiotics. Won't dramatically lower your blood pressure on its own. No strong evidence it burns fat or aids weight loss directly. Not a treatment for leukemia or cancer — early cell-study findings on sodium caseinate are far from clinical use. Won't fix milk intolerance or allergy — casein is actually a primary trigger of cow's milk allergies.
Evidence-Based Benefits
Casein protein supplementation, particularly pre-sleep intake, may improve anaerobic power, isokinetic strength, and lower-body muscular endurance in athletes, with synergistic effects when combined with probiotics (PMID: 40353739). Milk protein supplementation broadly has been associated with modest reductions in total cholesterol, systolic blood pressure, and triglycerides based on a meta-analysis of 65 RCTs (PMID: 40471664). Casein has also been used as a control comparator in studies showing it does not improve blood pressure as effectively as hemp seed protein hydrolysates (PMID: 38710445).
Moderate EvidenceEffective at: No established dose from provided studies; study doses ranged from ~25-50 g/day
Source: auto-research
Absorption & Bioavailability
Good — casein forms a gel in the stomach, slowing digestion and providing a sustained release of amino acids over 5–7 hours. This slow absorption is its defining characteristic compared to whey protein.
Red Flags to Watch For
- Casein is a leading cause of cow's milk protein allergy — people with milk allergies should avoid it entirely
- Some individuals sensitive to A1 beta-casein (found in most conventional milk) may experience digestive discomfort, mood changes, or cognitive issues
- Cardiovascular benefits (cholesterol, blood pressure) are modest — not a substitute for medication or medical advice
- Many products are heavily processed and may contain added sugars, artificial flavors, or fillers not reflected in protein content claims
- Pre-sleep dosing studies are small and mostly in young male athletes — results may not generalize to other populations
Research Sources
- PubMed
- NIH DSLD
This information is for educational purposes only and is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Last updated: 2026-04-06