Casein
A slow-digesting milk protein that provides a sustained release of amino acids.
Also known as: Micellar Casein • Calcium Caseinate
Overview
Casein is the main protein found in milk, making up about 80% of the total protein content, with whey accounting for the other 20%. Its defining characteristic is its slow rate of digestion. When casein enters the stomach, it forms a gel-like substance, or micelle, which slows down the emptying of the stomach and results in a gradual, steady release of amino acids into the bloodstream over several hours. This prolonged delivery of amino acids makes casein an ideal protein for situations where a sustained supply is beneficial, such as before bed or between meals. The slow release helps to promote a positive protein balance in the body for an extended period, which is anti-catabolic—meaning it helps to prevent muscle breakdown. This is in contrast to whey protein, which is rapidly digested and causes a quick spike in amino acid levels, making it more suitable for post-workout recovery. Casein is a complete protein, containing all the essential amino acids the body needs. It is also typically high in calcium, which supports bone health. Due to its slow-digesting nature, it can also enhance satiety, helping you feel fuller for longer, which can be beneficial for weight management.
Key Benefits
Sustained Amino Acid Release
The slow digestion of casein provides a steady supply of amino acids to muscle tissue for up to 7-8 hours, ideal for overnight recovery.
Anti-Catabolic Properties
By providing a prolonged source of amino acids, casein helps to reduce muscle protein breakdown, preserving lean muscle mass.
Increases Satiety
Its gelling effect in the stomach can help you feel full and satisfied, which can aid in controlling appetite and calorie intake.
Dosage & How to Take
A typical serving of casein protein powder is one scoop, which provides 20-30 grams of protein.
| Purpose | Dose | Notes |
|---|---|---|
| Overnight Muscle Recovery | 30-40 grams | Taken 30 minutes before bed. |
| Meal Replacement/Satiety | 20-40 grams | Used between meals to control hunger. |
Best Time to Take
Ideal before sleep or during long periods without food.
With or Without Food
Typically consumed as a shake mixed with water or milk, not as part of a large meal.
Forms & Bioavailability
| Form | Absorption | Best For | Notes |
|---|---|---|---|
| Micellar Casein | High | Slowest digestion, highest quality. | Created through a filtration process that preserves the natural structure of the casein micelles. |
| Calcium Caseinate | High | Often used in food production. | A form where casein is bound to calcium. It is more processed than micellar casein. |
Side Effects & Safety
Common
- Bloating
- Gas (in lactose-intolerant individuals)
Rare
- Allergic reactions
Contraindications
- Milk allergy
- Lactose intolerance (unless using a lactose-free product)
Interactions
No significant interactions have been reported.
Scientific Research
Protein ingestion before sleep increases muscle mass and strength gains during prolonged resistance-type exercise training in healthy young men
Pre-sleep protein ingestion, including casein, is an effective strategy to increase muscle mass and strength.
The effects of consuming a high protein diet (4.4 g/kg/d) on body composition in resistance-trained individuals
High protein diets, which can include casein, are effective for improving body composition.
Food Sources
Products With Casein
16 products in our database contain this ingredient
Frequently Asked Questions
Medical Disclaimer
This content is for educational and informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting any supplement regimen, especially if you have pre-existing health conditions or are taking medications. The statements on this page have not been evaluated by the Food and Drug Administration.