Rule 1 Casein NZ | Slow Digesting Protein

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:

All orders $60 and over receive Free* Shipping Nationwide 

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

Estimated Delivery Times*:

Auckland and North Island – Overnight

However many Auckland orders will be delivered the same day depending on what time the order is placed)

South Island – Overnight (For larger parcels allow 2 business days)

Same Day/Evening Express Shipping upgrade available at checkout for select suburbs*

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