Recover overnight and stay fuller for longer with Rule 1 Casein. Each serving delivers 25g of slow-digesting micellar casein protein, designed to release amino acids gradually for up to 8 hours. Ideal before bed or between meals, it supports muscle growth, reduces cravings, and keeps you in a positive nitrogen balance while you rest.

Why Choose Rule 1 Casein?

• 25g micellar casein protein – slow-release for sustained recovery.

• Extended amino acid release – supports muscles for up to 8 hours.

• Great for overnight use – helps recovery while you sleep.

• Thick, creamy texture – feels like a dessert-style shake.

• Low carb, low fat – lean-friendly nutrition.

• Gluten-free and easy to digest.

How to Use

• Mix 1 scoop of Rule 1 Casein with 250–300ml cold water or milk.

• Shake or stir until smooth and creamy.

• Best taken before bed or as a long-lasting protein snack.

Pro tip: Add less water and refrigerate for a pudding-style protein dessert.

Who’s It For?

• Athletes wanting recovery while they sleep.

• Gym-goers needing a filling, slow-digesting protein.

• People who snack late at night but want a leaner option.

• Anyone serious about round-the-clock muscle support.

FAQ

How is Rule 1 Casein different from whey protein?
Whey is fast-digesting and best post-workout, while casein is slow-digesting and ideal for overnight recovery.

Can I use it during the day?
Yes — it’s perfect between meals to help reduce cravings and keep you fuller.

Does it taste thick?
Yes — casein mixes into a creamier, thicker shake compared to whey.

Why Buy from Sprint Fit?

• 100% authentic Rule 1 supplements.

• Free NZ shipping on orders $60+.

• Same-day dispatch nationwide.

• Trusted by Kiwi athletes and fitness enthusiasts.

Rule 1 Casein – slow-release protein for overnight recovery and muscle growth.

Container Size: 907G (2Lb)
Serving Size: 1 Scoop (33g)
Servings Per Container: 28

Container Size: 1.8Kg (4Lb)
Serving Size: 1 Scoop (33g)
Servings Per Container:

We use NZ Couriers as our courier service using an international service. NZ Couriers provides our customers with fast and reliable delivery to destinations across their comprehensive AUS network. 

Standard orders over $60.00 receive free* shipping nationwide, excluding WA, NT, TAS.
Standard delivery starts from $12.90 per shipment for orders under $60.00 
Signature Required $14.90 per shipment. Please ensure you do not have the 'authority to leave' authorization set up at your address with NZ Couriers should you wish to use this service.
If you don't want NZ Couriers to leave your parcel unattended, please select the signature required option. This is especially recommended for high value orders. Neither NZ Couriers nor Sprint Fit are liable for parcels that are stolen, damaged or lost after an item has been delivered.

Final pick up each day is at 3.45pm Monday to Friday. 

*Excludes public holidays and weekends as courier is closed

Click here to view the full Shipping Details and Returns Policy.