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Optimum Nutrition Gold Standard 100% Casein, supplement product image

Optimum Nutrition Gold Standard Casein Review

This page provides an impartial review of Optimum Nutrition Gold Standard Casein.

Published: 18 August 2025 · Last updated: 04 September 2025
Editorial rating: 4.6/5
24 g protein 130 kcal Low sugar

A slow‑release casein powder positioned for overnight use.

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Quick verdict

Gold Standard Casein delivers 24 g protein per scoop from micellar casein. Marketed for sustained amino acid release, it’s popular as a “bedtime shake.”

How we review

At Protein Pitstop, reviews are based on editorial research — not product trials. We assess:

  • Nutrition labels
  • Amazon customer feedback
  • Brand transparency
  • Suitability for dietary preferences

We do not test products hands‑on.

Nutrition & ingredients

Each serving provides 24 g of protein, 1 g of fat and 3 g of carbohydrates. Micellar casein thickens when mixed, creating a slow‑digesting texture. It’s sweetened with sucralose. The powder contains some lactose but is lower than many whey blends.

Taste & mixability

Customer reviews often note a thick, dessert‑like shake. Chocolate Peanut Butter and Creamy Vanilla are favourites. It mixes best in a blender due to casein’s viscosity and works well in puddings and recipes like overnight oats.

Use cases

Casein is marketed as suitable before bed or between meals for satiety. Customers frequently highlight feeling fuller for longer compared to whey.

Value

Priced similarly to whey. Because casein is typically consumed once daily, tubs last longer. Users rate it good value for convenience and taste.

Pros & cons

Pros

  • 24 g slow‑digesting protein per scoop
  • Thick, filling texture
  • Versatile in recipes

Cons

  • Contains lactose
  • Thicker than whey (not everyone likes)
  • Not ideal immediately post‑workout

Who it suits

Good fit if: You want a slow‑release protein for overnight or satiety between meals.

Skip if: You are lactose‑intolerant or dislike thick shakes.

Alternatives

Fast whey: ON Gold Standard Whey

Lactose‑free isolate: Dymatize ISO100

Plant option: Form Performance Protein

FAQs

When should I take casein protein?

The best time is before bed to provide a steady supply of amino acids overnight. You can also use it between meals for prolonged satiety.

Is casein better than whey?

Neither is inherently better. Whey digests quickly and is ideal around workouts, while casein digests slowly and is great before bed. Many athletes use both at different times.

Does this product contain lactose?

It contains a small amount of lactose from the casein. Those with mild intolerance may tolerate it; others should opt for a lactose‑free or plant‑based protein.

Can I cook with casein?

Yes, though heat can affect its thickening properties. It works well in puddings, pancakes and overnight oats. You may need extra liquid to offset its viscosity.

Is casein safe for people with milk allergies?

No. Casein is one of the proteins that cause milk allergies. People with milk allergy should avoid it and use a hypoallergenic plant protein instead.

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