Serious Mass Chocolate Peanut Butter 5.45kg
by Optimum Nutrition
Optimum Nutrition Serious Mass is a long-established high-calorie mass gainer delivering 1,263 kcal and 50g protein per 334g serving, targeting hard gainers who struggle to consume sufficient calories through food alone. Best for Hard gainers with fast metabolisms who genuinely struggle to reach a calorie surplus through food and Individuals recovering from illness, surgery, or appetite loss needing a calorically dense supplement.
According to the AIScored 0–100 scoring system, Serious Mass Chocolate Peanut Butter 5.45kg by Optimum Nutrition scores 64.0/100, ranking #19 out of 23 products in Mass Gainers (2026). Strongest category: Effectiveness (78.0/100). Weakest: Certifications (32.0/100).
Is Serious Mass Chocolate Peanut Bu... worth buying?
“Serious Mass delivers 1,263 calories and 50g of protein per serving, which is genuinely what hard gainers need, and the chocolate peanut butter flavour is actually quite nice. At 64/100, it's a straightforward bulk supplement that gets the job done, but the 3g creatine per serving does add value if you're training for strength.”
What Do Reviewers Say About Serious Mass Chocolate Peanut Butter 5.45kg?
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 Peanut Butter 5.45kg score?
Detailed score breakdown and key findings from our analysis of 11 reviews across 2 sources.
Pros
- +Very high calorie density (1,263 kcal per serving) — effective for hard gainers who struggle to eat enough
- +50g protein per serving from multiple sources (whey concentrate, calcium caseinate, egg albumen) for sustained amino acid release
- +3g creatine monohydrate added per serving — supports strength and muscle performance
- +Comprehensive 25-vitamin and mineral blend covers most micronutrient requirements at meaningful doses
- +Strong long-term brand trust with consistent results reported across years of use
Cons
- -Maltodextrin is the primary carbohydrate source — very high glycaemic index, not suitable for those managing blood sugar
- -334g serving size requires a blender; clumping reported with standard shaker bottles
- -Occasional batch flavour inconsistency reported by repeat buyers on subscribe-and-save
- -Not third-party tested — no independent verification of label accuracy or contaminant screening
Best For
Watch Out
- !26g sugar and maltodextrin-dominant carb profile — unsuitable for diabetics or those monitoring blood glucose
- !334g per serving is impractically large for many users; splitting into two smaller shakes is common practice
- !Contains multiple major allergens: milk, egg, wheat, gluten; may contain soy and peanuts
- !A full-size blender is strongly recommended — standard shaker bottles produce clumpy, uneven results
What is Serious Mass Chocolate Peanut Butter 5.45kg?
Serious Mass Chocolate Peanut Butter 5.45kg is a mass gainers product by Optimum Nutrition in powder form, scoring 64.0/100 on AIScored.
- • Serious weight gain requires serious calories.
- • Optimum Nutrition Serious Mass is the ultimate weight gain formula.
- • For muscle building and weight gain More than 1260 kcal per serving to help boost your calorie intake 50g protein per serving 25 vitamins & supplements Those who need the extra calories most often have the toughest time consuming enough of them.
- • For many aspiring to be bigger, Serious Mass is the ultimate in weight gain formulas.
- • With over 1,250 calories per serving to boost daily calorie intake, 50g high protein to support muscle growth and repair, over 250g carbohydrates, and now with 3g of added creatine per serving to support performance, you’ve got nothing to lose and lots to gain.
- • It is time to stop thinking small and get serious – SERIOUS MASS.
- • Use anytime, it is quick, convenient and easy to prepare.
- • Serious Mass is ideal between meals, after weight training as part of your recovery routine and before bed.
- • Just mix two scoops of Serious Mass (330g) with 710ml of water to create a tasty, calorie-packed shake.
What's Inside Serious Mass Chocolate Peanut Butter 5.45kg?
Serious Mass Chocolate Peanut Butter 5.45kg contains 45 active ingredients: Per, Fat, of which saturates, Carbohydrates and more.
Active Ingredients
- Per
- 100g / Per 2 scoops 334g: Energy 1582 kJ / 378 kcal / 5283 kJ /1263 kcal
- Fat
- 1,7 g / 5
- of which saturates
- 0,7 g / 2
- Carbohydrates
- 75 g / 251 g
- of which sugars
- 7,7 g / 26 g
- Protein
- 15 g / 50 g
- Salt
- 0,47 g / 1
- Fibre
- 1,0 g / 3
- Vitamin A
- 192 µg (24%)* / 640 µg (80%)*
- Vitamin D
- 1,2 µg (24%)* / 4
- Vitamin E
- 2,7 mg (22%)* / 9
- Vitamin C
- 19 mg (24%)* / 64 mg (80%)*
- Thiamin
- 0,27 mg (24%)* / 0
- Riboflavin
- 0,34 mg (25%)* / 1
- Niacin
- 3,9 mg (24%)* / 13 mg (81%)*
- Folic Acid
- 45,1 µg (23%)* / 151 µg (75%)*
- Biotin
- 11 µg (22%)* / 37 µg (75%)*
- Pantothenic Acid
- 1,4 mg (23%)* / 4
- Calcium
- 179 mg (22%)*/ 600 mg (75%)*
- Phosphorus
- 159 mg (23%)* / 532 mg (76%)*
- Magnesium
- 85,8 mg (23%)* / 287 mg (76%)*
- Iron
- 5,4 mg (39%)* / 18 mg (129%)*
- Zinc
- 3,2 mg (32%)* / 11 mg (106%)*
- Copper
- 0,41 mg (41%)* / 1
- Manganese
- 0,60 mg (30%)* / 2
- Selenium
- 17 µg (30%)* / 46 µg (101%)*
- Chromium
- 14 µg (34%)* / 46 µg (114%)*
- Iodine
- 44,9 µg (30%)*/ 150 µg (100%)*
- Creatine
- 0,9 g / 3
- Fluoride
- 1,0 mg (30%)* / 3
- 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) (Emulsifier: Soy Lecithin), Fat-Reduced Cocoa Powder (2.3%), Flavouring, Minerals (Sodium Chloride, Dipotassium Phosphate, Ferric Pyrophosphate, Zinc Oxide, Cupric Gluconate, Manganese Sulphate, Chromium III Chloride Hexahydrate, Potassium Iodide), Egg Albumen, Medium Chain Triglycerides, Creatine Monohydrate, Choline Bitartrate, L-Glutamine, Glutamine Peptides [Wheat], Whey Powder (Milk), Inositol,
Is Serious Mass Chocolate Peanut Butter 5.45kg 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:
Effectiveness
How well the product delivers its claimed benefits, based on reviews and ingredient evidence.
Ingredient Quality
Bioavailable forms, clinically effective dosages, clean label, minimal fillers.
Value for Money
Price relative to ingredient quality, dosage count, and effectiveness.
Side Effects Profile
Higher score = fewer side effects. 100 means virtually no adverse reactions reported.
Certifications & Testing
Third-party lab testing, GMP certification, and independent quality verification.
Overall Score
Weighted combination of all factors. Our bottom-line recommendation.
How Does Serious Mass Chocolate Peanut Butter 5.45kg Compare?
See how this product stacks up against the top-rated mass gainers in our database.
| Product | Score | Price |
|---|---|---|
| Serious Mass Chocolate Peanut Bu... (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 Peanut Butter 5.45kg worth buying in 2026? ▼
What is the best price for Serious Mass Chocolate Peanut Butter 5.45kg in the UK? ▼
What are the pros and cons of Serious Mass Chocolate Peanut Butter 5.45kg? ▼
Is Serious Mass Chocolate Peanut Butter 5.45kg third-party tested? ▼
How does Serious Mass Chocolate Peanut Butter 5.45kg compare to Critical Mass Professional Lean Mass Gainer Banana 2.4kg (16 Servings)? ▼
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.
What Are Other Top Mass Gainers?
Other top-rated mass gainers you might want to compare.
Critical Mass Professional Lean Mass Gainer Banana 2.4kg (16 Servings)
Applied Nutrition
Critical Mass Professional Lean Mass Gainer Chocolate 2.4Kg (40 Servings)
Applied Nutrition
Critical Mass Professional Lean Mass Gainer Banana 6kg (40 Servings)
Applied Nutrition
Bulk Complete Mass Gainer
Bulk
Feedback & Suggestions
Spotted an issue? Wrong price, incorrect data, or something else off? Let us know and we'll fix it.
Missing a product you'd like us to review? Tell us the product name and we'll consider adding it.