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Serious Mass Chocolate 5.4kg

by Optimum Nutrition

11 reviews analysed · 2 sources · Last verified: 01 Mar 2026 · Price data: 18 Feb 2026 · Confidence: 37% · Reviewed by Bart, Health & Tech Enthusiast
Serious Mass Chocolate 5.4kg
64
Overall Score
Above Average

Compare Prices

Amazon UK
£52.95 View →
Holland & Barrett
£58.00 View →
Verdict: Above Average View Mass Gainers Rankings →

Optimum Nutrition Serious Mass is a long-established, high-calorie mass gainer delivering 1,263 kcal, 50g protein, and 251g carbohydrates per 334g serving — one of the largest serving sizes in its category. Best for Hard gainers struggling to consume sufficient calories through whole food alone and People with poor appetite or conditions affecting normal food intake.

According to the AIScored 0–100 scoring system, Serious Mass Chocolate 5.4kg by Optimum Nutrition scores 64.0/100, ranking #18 out of 23 products in Mass Gainers (2026). Strongest category: Effectiveness (73.0/100). Weakest: Certifications (30.0/100).

Data quality note: this page currently has limited evidence coverage (low review/source volume or lower confidence). Treat this as directional and cross-check with primary sources.

Is Serious Mass Chocolate 5.4kg worth buying?

“Optimum Nutrition's Serious Mass Chocolate scores 64/100 and delivers 1,263 calories per 334g serving, one of the largest portions you'll find in a mass gainer. Users report genuine weight gain results, and the blend of whey concentrate, casein, and egg protein provides consistent amino acid support throughout the day.”

— AIScored Editorial Team, Mar 2026

What Do Reviewers Say About Serious Mass Chocolate 5.4kg?

Sample excerpts from currently available source material used in this product analysis.

"Have this product on subscribe and save so only recently opened my most recent delivery, and there is next to no flavour, never had this issue before, but with this bag it taste horrible"

"I only use this brand of mass gainer… reason being it sits will in my digestive system, it definitely does what it supposed to do. I have used other brands, cheaper brands but they do not pack the punch this do 💪 I have literally been buyin..."

"It's helping me put on weight. I added a tablespoon of peanut butter and a banana, tastes really good with the strawberry one. This seems to be the best mass gainer, I've looked around and this is always said to be the best with approved in..."

"I don’t use this protein for the gym I use it cos I struggle to eat normal food and so this sometimes becomes my only source of food and with 1250 calories per shake I know if I drink 2 a day I’ll get all the nutrients I need infact probabl..."

"This protein powder is an excellent for anyone serious about gaining mass. The large size offers fantastic value, and the mix is effective and potent. It mixes well, taste good and is essential for hitting those high-calorie and high-protei..."

How does Serious Mass Chocolate 5.4kg score?

Detailed score breakdown and key findings from our analysis of 11 reviews across 2 sources.

Effectiveness How well the product works based on user reviews
73.0/100
Good
Ingredient Quality Clean label, bioavailable forms, minimal fillers
60.0/100
Average
Value for Money Price relative to quality and quantity
67.0/100
Average
Side Effects Profile Higher = fewer/milder side effects reported
58.0/100
Average
Certifications & Testing Third-party testing, GMP, and quality certifications
30.0/100
Below Average
Overall Score Weighted overall recommendation
64.0/100
Average

Pros

  • +Proven track record for actual mass and weight gain, with multiple reviewers reporting visible results
  • +High calorie density (1,263 kcal/serving) makes it practical for those struggling to meet caloric goals through food alone
  • +Multi-source protein blend (whey concentrate, casein, egg albumen) supports sustained amino acid delivery
  • +Comprehensive micronutrient profile covering 20+ vitamins and minerals per serving
  • +Large 5.4kg bag offers strong cost-per-calorie value versus smaller competitors

Cons

  • -Extremely large 334g serving requires a blender — not shaker-compatible without clumping
  • -Maltodextrin is the primary carbohydrate source, producing a high glycaemic response unsuitable for those managing blood sugar
  • -Digestive discomfort and bloating reported by some users, particularly from the large carbohydrate load
  • -Flavour inconsistency flagged across batches; not third-party tested for label accuracy or contaminants

Best For

Hard gainers struggling to consume sufficient calories through whole food alone People with poor appetite or conditions affecting normal food intake Beginner to intermediate weightlifters in a deliberate bulking phase Athletes with very high daily caloric requirements (3,500+ kcal)

Watch Out

  • !Bloating and gas are a recurring complaint — starting with half servings is advisable
  • !334g serving will not fit most standard shaker bottles; a blender is effectively required
  • !Maltodextrin-heavy formula not appropriate for anyone with insulin sensitivity or diabetes
  • !Contains milk, egg, gluten, and wheat — unsuitable for those with relevant allergies or intolerances
  • !Creatine dose (3g/serving) is slightly below the evidence-based 5g/day maintenance threshold

What is Serious Mass Chocolate 5.4kg?

Serious Mass Chocolate 5.4kg is a mass gainers product by Optimum Nutrition in powder form, scoring 64.0/100 on AIScored.

  • What Is It: A high‑calorie weight gainer that supports muscle building and weight gain, delivering 1,250 calories per serving to help boost calorie intake.
  • Formulated for those who struggle to consume enough food, Serious Mass supplies concentrated macronutrients to assist substantial mass gain.
  • Key Benefits: Formulated to support muscle building and weight gain, supplying concentrated calories and macronutrients for mass accrual.
  • Provides 1,250 calories per serving to help boost daily calorie intake for individuals needing substantial additional energy.
  • Delivers 50 g of protein per serving to help build and maintain muscle as part of an increased‑calorie nutritional plan.
  • Contains over 250 g of carbohydrates per serving to help support muscle recovery and replenish glycogen stores after exercise.
  • Includes 3 g added creatine per serving, included to help support performance.
  • How To Use: Add 334 g (~ 2 heaped scoops) to a blender filled with 710 ml of water and blend for 30–45 seconds until thoroughly mixed.
  • Store in a cool, dry place.
  • Key Ingredients: Key actives per serving: 50 g high protein to help build and maintain muscle, over 250 g carbohydrates to help support muscle recovery and refuel glycogen, plus 3 g added creatine to help support performance.

What's Inside Serious Mass Chocolate 5.4kg?

Serious Mass Chocolate 5.4kg contains 43 active ingredients: Per, Fat, of which saturates, Carbohydrates and more.

Active Ingredients

Per
100g / Per 334g Serving : Energy 1582kJ / 5284kJ / 378kcal / 1263kcal
Fat
1.7g / 5.5g
of which saturates
0.7g / 2.4g
Carbohydrates
75g / 251g
of which sugars
7.7g / 26g
Protein
15g / 50g
Salt
0.47g / 1.56g
Vitamin D
1.2µg / 4.0µg
Vitamin E
2.7mg / 9.0mg
Vitamin K
22µg / 75µg
Vitamin C
19mg / 64mg
Thiamin
0.27mg / 0.89mg
Riboflavin
0.34mg / 1.1mg
Niacin
3.9mg / 13mg
Folic Acid
45.1µg / 151µg
Biotin
11µg / 37µg
Pantothenic Acid
1.4mg / 4.5mg
Calcium
180mg / 600mg
Phosphorus
159mg / 532mg
Magnesium
85.8mg / 287mg
Iron
5.4mg / 18mg
Zinc
3.2mg / 11mg
Copper
0.41mg / 1.4mg
Manganese
0.60mg / 2.0mg
Fluoride
1.0mg / 3.5mg
Selenium
17µg / 55µg
Chromium
14µg / 46µg
Molybdenum
17µg / 57µg
Creatine
0.9g / 3.0g Macro Nutrient table: Energy Kcal per 100g 378Kcal
Energy kJ per
100g 1582kJ
Fats per
100g 1.7g
Of which Saturates per
100g 0.7g
Carbohydrates per
100g 75g
Sugar per
100g 7.7g
Protein per
100g 15g
Salt per
100g 0.47g
Fats per serving
5.5g
Of which Saturates per serving
2.4g
Carbohydrates per serving
251g
Sugar per serving
26g
Protein per serving
50g
Salt per serving
1.56g
Serving size
334g

Other Ingredients

Maltodextrin, WHEY Protein Concentrate [MILK], Calcium CASEINATE [MILK], Fat-Reduced Cocoa Powder, Creatine Monohydrate, Flavouring, MILK Mineral Complex, Medium Chain Triglycerides [MILK], EGG Albumen, Sodium Chloride, Dipotassium Phosphate, Vitamin & Mineral Blend (Sodium L-Ascorbate, Ferric Pyrophosphate, D-Alpha-Tocopheryl Acetate, Nicotinamide, Zinc Oxide, Retinyl Acetate, Calcium D-Pantothenate, Sodium Fluoride, Manganese Sulphate, Potassium Iodate, Cyanocobalamin, D-Biotin,

Allergens: Contains: Eggs, Gluten, Lactose, Milk, Peanuts may contain, Soy may contain, Wheat

Is Serious Mass Chocolate 5.4kg Independently Tested?

?

No Third-Party Testing Visible

We could not find evidence of independent third-party testing for this product. This doesn't mean it's unsafe, but independent verification provides additional assurance.

How We Score Supplements

Our methodology analyses review data, ingredient science, and product information, then scores each product on a 0-100 scale across evidence-based categories:

1

Effectiveness

How well the product delivers its claimed benefits, based on reviews and ingredient evidence.

2

Ingredient Quality

Bioavailable forms, clinically effective dosages, clean label, minimal fillers.

3

Value for Money

Price relative to ingredient quality, dosage count, and effectiveness.

4

Side Effects Profile

Higher score = fewer side effects. 100 means virtually no adverse reactions reported.

5

Certifications & Testing

Third-party lab testing, GMP certification, and independent quality verification.

6

Overall Score

Weighted combination of all factors. Our bottom-line recommendation.

How Does Serious Mass Chocolate 5.4kg Compare?

See how this product stacks up against the top-rated mass gainers in our database.

Product Score Price
Serious Mass Chocolate 5.4kg (this) 64.0 £52.95
Critical Mass Professional Lean ... 80.0 £40.00

Price History (90 days)

Quick Facts

Form
powder
Serving
1 serving
Vegan
No

Frequently Asked Questions

Is Serious Mass Chocolate 5.4kg worth buying in 2026?
Serious Mass Chocolate 5.4kg scores 64.0/100 in our analysis, based on 11 reviews. Optimum Nutrition Serious Mass is a long-established, high-calorie mass gainer delivering 1,263 kcal, 50g protein, and 251g carbohydrates per 334g serving — one of the largest serving sizes in its category. Reviewers are predominantly positive, with ...
What is the best price for Serious Mass Chocolate 5.4kg in the UK?
The best price we found is £52.95 at Amazon UK. We compare prices from 2 UK retailers and update them regularly.
What are the pros and cons of Serious Mass Chocolate 5.4kg?
Pros: Proven track record for actual mass and weight gain, with multiple reviewers reporting visible results. High calorie density (1,263 kcal/serving) makes it practical for those struggling to meet caloric goals through food alone. Multi-source protein blend (whey concentrate, casein, egg albumen) supports sustained amino acid delivery. Cons: Extremely large 334g serving requires a blender — not shaker-compatible without clumping. Maltodextrin is the primary carbohydrate source, producing a high glycaemic response unsuitable for those managing blood sugar. Digestive discomfort and bloating reported by some users, particularly from the large carbohydrate load.
Is Serious Mass Chocolate 5.4kg third-party tested?
We could not find evidence of third-party testing for this product. While this does not mean the product is unsafe, independent testing provides additional quality assurance.
How does Serious Mass Chocolate 5.4kg compare to Critical Mass Professional Lean Mass Gainer Banana 2.4kg (16 Servings)?
Serious Mass Chocolate 5.4kg scores 64.0/100 while Critical Mass Professional Lean Mass Gainer Banana 2.4kg (16 Servings) scores 80.0/100. Read full comparison →

Disclaimer: AIScored provides research-backed summaries based on publicly available reviews and product information. This is not medical advice. Always consult a healthcare professional before starting any supplement regimen. Affiliate links may earn us a commission at no extra cost to you.

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