Optimum Nutrition Casein Chocolate vs Myprotein Slow-Release Casein

Q: Is Optimum Nutrition Casein Chocolate worth the price compared to Myprotein Slow-Release Casein?

Optimum Nutrition Casein Chocolate scores 70.0/100 for value, while Myprotein Slow-Release Casein scores 82.0/100. Myprotein Slow-Release Casein delivers better value overall.

Side-by-side comparison of scores, ingredients, prices and real customer feedback for Optimum Nutrition Casein Chocolate and Myprotein Slow-Release Casein.

Last verified: 01 Mar 2026 · Based on 17 reviews

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Our Verdict: Optimum Nutrition Casein Chocolate or Myprotein Slow-Release Casein?

— AIScored Editorial Team

80.0

Score Summary

Optimum Nutrition Casein Chocolate scores 80.0/100 vs Myprotein Slow-Release Casein at 70.0/100. Optimum Nutrition Casein Chocolate wins on effectiveness, ingredient quality, side effects. Myprotein Slow-Release Casein is stronger on value for money.

Optimum Nutrition Casein Chocolate vs Myprotein Slow-Release Casein: What Does the Data Say?

Gold Standard 100% Casein Powder Chocolate provides 24g of protein per 33g serving, whereas Myprotein Slow-Release Casein offers 23g from a 30g scoop. Myprotein uses micellar casein and avoids carrageenan, using xanthan gum as a single thickener. Gold Standard 100% Casein Powder Chocolate contains 1.5g of sugar and 0.7g of fat. It scores higher for ingredient quality at 80/100 compared to 68/100 for the Myprotein option.

Muscle-building athletes wanting overnight support should choose Gold Standard 100% Casein Powder Chocolate. It is better for people who want to feel full until lunchtime. However, it costs £50.00 for 924g. Budget-conscious gym-goers will prefer Myprotein Slow-Release Casein. It costs £67.64 for a much larger 2.5kg tub. This gives it a superior value score of 82/100 against 70/100 for the Optimum Nutrition product. Gold Standard 100% Casein Powder Chocolate wins overall with 80/100 compared to 70/100 for Myprotein.

Gold Standard 100% Casein Powder Chocolate is known for its smooth texture and excellent taste. You should mix it with water or semi-skimmed milk to avoid clumps. Myprotein Slow-Release Casein is useful for making high-protein desserts. It contains soy lecithin. People with allergies must be careful as it may also contain gluten or nuts. Gold Standard 100% Casein Powder Chocolate wins on effectiveness with a score of 80/100.

How Do the Scores Compare?

Gold Standard 100% Casein P...

Myprotein Slow-Release Casein 2.5kg

	Gold Standard 100% Casein P... Optimum Nutrition	Myprotein Slow-Release Casein 2.5kg Myprotein
Overall Score	80.0	70.0
Effectiveness	80.0/100 Best	74.0/100
Ingredient Quality	80.0/100 Best	68.0/100
Value for Money	70.0/100	82.0/100 Best
Side Effects	80.0/100 Best	76.0/100
Certifications	40.0/100 Best	32.0/100
Best Price	£45.00 Holland & Barrett →	£39.36 Amazon UK → Cheapest
Price per Serving	N/A	£0.47 83 servings
Form	powder	Powder
Dose	None	23g protein per 30g serving
Third-Party Tested	✗ No	✗ No
Reviews Analysed	4	13

Gold Standard 100% Casein Powder...

Pros

✓Excellent taste and smooth texture (mentioned by multiple reviewers)
✓High protein content (24g per 33g serving) with low sugar (1.5g) and minimal fat (0.7g)
✓Sustained satiety and fullness (reviewers report lasting until lunchtime)
✓Strong brand reputation with loyal customer base citing consistent quality

Cons

✗Mixing can be clumpy with full-fat milk; better with water or semi-skimmed milk
✗Premium pricing compared to competitor casein products
✗Not third-party tested (no NSF, Informed Choice, or similar certification)
✗Contains artificial sweeteners (Acesulfame K, Sucralose) and thickening gums which may affect digestion in sensitive individuals

Best For

Muscle-building athletes seeking overnight protein support People prioritizing satiety and sustained fullness between meals Those preferring slow-release protein over fast-digesting options Existing Optimum Nutrition brand loyalists Night-time protein supplementation (casein is ideal pre-sleep)

Holland & Barrett £45.00 Amazon UK £91.83

View full review →

Myprotein Slow-Release Casein 2.5kg

Pros

✓Micellar casein — the most bioavailable, slowest-digesting form ideal for overnight recovery
✓Cleaner additive profile than ON Gold Standard Casein — single thickener (xanthan gum), no carrageenan
✓Strong value for money — casein at Myprotein pricing with 83 servings per 2.5kg tub
✓Good mixability reported — dissolves quickly in liquid, uncommon for casein

Cons

✗Not third-party tested (Informed Sport, NSF) — relevant for athletes subject to testing
✗Contains soy lecithin — unsuitable for soy-allergic users; may contain gluten, egg, nuts
✗Casein taste can be chalky or overly sweet — one reviewer noted sweetness as a concern
✗Myprotein customer service has recurring complaints; discount codes not auto-applied at checkout

Best For

Bodybuilders and strength athletes using casein before bed for overnight muscle protein synthesis Budget-conscious gym-goers wanting slow-release protein at a lower price point than whey isolate People blending casein with whey concentrate for improved texture in shakes or high-protein desserts Anyone wanting a UK-made casein with a cleaner ingredient list than American alternatives

Amazon UK £39.36

View full review →

Score Breakdown: Optimum Nutrition Casein Chocolate vs Myprotein Slow-Release Casein

Optimum Nutrition Casein Chocolate Winner 80.0/100

Optimum Nutrition's Gold Standard 100% Casein Powder delivers 24g of micellar casein per serving with minimal fat and sugar, designed for slow protein digestion.

Effectiveness

Gold Standard 10..

80.0/100

Myprotein Slow-R..

74.0/100

Ingredient Quality

Gold Standard 10..

80.0/100

Myprotein Slow-R..

68.0/100

Value for Money

Gold Standard 10..

70.0/100

Myprotein Slow-R..

82.0/100

Side Effects

Gold Standard 10..

80.0/100

Myprotein Slow-R..

76.0/100

Certifications

Gold Standard 10..

40.0/100

Myprotein Slow-R..

32.0/100

What are the key differences?

Optimum Nutrition Casein Chocolate is best for: Muscle-building athletes seeking overnight protein support, People prioritizing satiety and sustained fullness between meals

Myprotein Slow-Release Casein is best for: Bodybuilders and strength athletes using casein before bed for overnight muscle protein synthesis, Budget-conscious gym-goers wanting slow-release protein at a lower price point than whey isolate

Frequently Asked Questions

Which is better, Optimum Nutrition Casein Chocolate or Myprotein Slow-Release Casein? ▼

Gold Standard 100% Casein Powder Chocolate 924g wins with a score of 80.0/100 because it has 24g of protein and only 1.5g of sugar. Budget-conscious gym-goers should buy Myprotein Slow-Release Casein 2.5kg to get 83 servings for £67.64. Optimum Nutrition Casein Chocolate scores 80.0/100 overall while Myprotein Slow-Release Casein scores 70.0/100. Optimum Nutrition Casein Chocolate comes out ahead, scoring higher on effectiveness (80.0 vs 74.0). Optimum Nutrition Casein Chocolate is best suited for Muscle-building athletes seeking overnight protein support and People prioritizing satiety and sustained fullness between meals. Myprotein Slow-Release Casein is better for Bodybuilders and strength athletes using casein before bed for overnight muscle protein synthesis and Budget-conscious gym-goers wanting slow-release protein at a lower price point than whey isolate.

Is Optimum Nutrition Casein Chocolate worth the price compared to Myprotein Slow-Release Casein? ▼

Optimum Nutrition Casein Chocolate costs £45.00 while Myprotein Slow-Release Casein is £39.36. For value, Optimum Nutrition Casein Chocolate scores 70.0/100 vs Myprotein Slow-Release Casein's 82.0/100. Myprotein Slow-Release Casein delivers better value relative to its quality. Note that Optimum Nutrition Casein Chocolate comes as powder while Myprotein Slow-Release Casein is powder, which may affect your preference.

Which has fewer side effects? ▼

Optimum Nutrition Casein Chocolate scores 80.0/100 for side effects (higher means fewer reported issues) while Myprotein Slow-Release Casein scores 76.0/100. Reviewers report fewer side effects with Optimum Nutrition Casein Chocolate. For certification and testing, Optimum Nutrition Casein Chocolate scores 40.0/100 vs Myprotein Slow-Release Casein's 32.0/100. Always consult a healthcare professional before starting any supplement.