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Casein protein

Supplement protein fitness
Aka: micellar casein, calcium caseinate
Brands seen in Singapore: California Gold Nutrition, Nutricost, NOW Foods, ALLMAX, Optimum Nutrition
Third-party tested: Optimum Nutrition certifies other products with NSF Certified for Sport, but nothing for casein protein.Certification is granted per product, so check the tub you actually own. Not being listed is not the same as failing.
Not medical advice. Check with your doctor or pharmacist before you start, stop or change the timing of anything you take.
How to use
What it’s for
Overnight muscle protein synthesis · daily protein total
When to take
30–40 g in the half hour before sleep in ISSN's stand
Take with
Water or milk · slower to digest than whey
Pros & cons
Pros
  • ISSN: 30–40 g pre-sleep raised overnight synthesis
  • Amino acids released slowly through the night
  • 9.3% leucine — behind whey, ahead of most proteins
Cons
  • Slower mps response than whey at rest and after lifting
  • 8 weeks of 54 g: morning vs evening made no difference
  • A milk protein — not an option with milk allergy
Sources
  1. NIH ODS — Exercise and Athletic Performance (HP), protein implications for use · read 2026-08-27
    what it says
    “Digestion of casein, the main complete protein in milk, is slower than that of whey, so the release of amino acids from casein into the blood is slower”
  2. NIH ODS — Exercise and Athletic Performance (HP), pre-sleep protein · read 2026-08-27
    what it says
    “Participants in these studies consumed a bedtime drink containing 27.5 or 40 g of the milk protein casein, which increased circulating amino acid levels throughout the night”
  3. NIH ODS — Dietary Supplements for Exercise and Athletic Performance (Health Professional), protein safety (updated 1 Apr 2024) · read 2026-08-27
    what it says
    “The Food and Nutrition Board has not set a UL for protein, noting that the risk of adverse effects from excess protein from food is very low”
  4. ISSN position stand: protein and exercise (Jäger et al., JISSN 2017) — position statement on pre-sleep casein · read 2026-08-27
    what it says
    “Pre-sleep casein protein intake (30–40 g) provides increases in overnight MPS and metabolic rate without influencing lipolysis”
  5. Jäger et al., JISSN 2017 — milk proteins section · read 2026-08-27
    what it says
    “Comparison of the quality of whey and casein reveal that these two proteins routinely contain the highest leucine content of all other protein sources at 11% and 9.3%, respectively”
  6. Jäger et al., JISSN 2017 — Tang et al. comparison of whey, soy and micellar casein · read 2026-08-27
    what it says
    “These authors reported that the ability of soy to stimulate MPS was greater than casein, but less than whey, at rest and in response to an acute resistance exercise stimulus”
  7. Jäger et al., JISSN 2017 — Antonio et al. morning vs evening casein · read 2026-08-27
    what it says
    “The authors reported no differences in body composition or performance between the morning and evening casein supplementation groups”
  8. ISSN position stand: protein and exercise (Jäger et al., JISSN 2017) — safety section · read 2026-08-27
    what it says
    “people in renal failure benefit from protein-restricted diets, but extending this pathophysiology to otherwise healthy exercise-trained individuals who are not clinically compromised is inappropriate”
  9. FDA — Daily Value on the Nutrition and Supplement Facts Labels, Reference Guide: Daily Values for Nutrients (content current as of 03/05/2024) · read 2026-08-27
    what it says
    “DVs are the recommended amounts of nutrients to consume or not to exceed each day … Protein | 50g”
  10. HSA — Guidelines on Prohibited and Restricted Ingredients in Health Supplements and Traditional Medicines, GL-CHPB-1-012 Rev 001 (Oct 2025), Annexes A/B · read 2026-08-27
    what it says
    “The objective of this guideline is to highlight the substances of concern when used in HS and TM and is not meant to be an exhaustive list”
  11. iHerb Singapore — Casein Protein category page, default sort · read 2026-08-27
    what it says
    “Casein Protein: Slow-Release Powder for Recovery | iHerb … Casein Protein 1 - 31 of 31 results”
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Updated 2026-08-30. Every line above traces to a numbered source. Kozen-X is not a medical device and does not give medical advice. It lists what published sources have written down — nothing more. A pair not listed is unrecorded, not cleared. Before you start, stop or re-time anything, talk to your doctor or pharmacist.