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Serious Mass Strawberry 5.4kg

by Optimum Nutrition

12 reviews analysed · 2 sources · Last verified: 01 Mar 2026 · Price data: 19 Feb 2026 · Confidence: 40% · Reviewed by Bart, Health & Tech Enthusiast
Serious Mass Strawberry 5.4kg
70
Overall Score
Good

Compare Prices

Amazon UK
£52.95 View →
Holland & Barrett
£58.00 View →

Optimum Nutrition Serious Mass is a long-established, high-calorie mass gainer delivering 1,258 kcal and 53 g of blended protein per 334 g serving — one of the largest single-serve calorie loads commercially available. Best for Hardgainers who struggle to meet daily caloric targets through food alone and Individuals with reduced appetite or difficulty eating full meals.

According to the AIScored 0–100 scoring system, Serious Mass Strawberry 5.4kg by Optimum Nutrition scores 70.0/100, ranking #11 out of 23 products in Mass Gainers (2026). Strongest category: Effectiveness (80.0/100). Weakest: Certifications (44.0/100).

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 Strawberry 5.4kg worth buying?

“Serious Mass from Optimum Nutrition scores 70/100 and delivers an impressive 1,258 calories per 334g serving, making it one of the market's densest mass gainers for hardgainers. The strawberry flavour is genuinely pleasant like a milkshake, and many long-term users report reliable weight and muscle gains over months of consistent use.”

— AIScored Editorial Team, Mar 2026

What Do Reviewers Say About Serious Mass Strawberry 5.4kg?

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

"Just tried. My first try now taste good I like it but at half bottle of drink I start feeling my head heavier. I guess I have to use only one scoop instead of 2 scoops."

"Verify good. Yes I have put on kilos on am beater good very tahnk you there's a bit stronger ones like. ultra strong on massive mass strongerrrr yesssss good 10 pocent to2 ultra strong in mass protein thanks youuuuuuuuuuuu love internationa..."

"Lovely. Bought the strawberry flavour, tastes very nice just like having a strawberry milkshake, put on a few 1lbs aswell"

"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..."

How does Serious Mass Strawberry 5.4kg score?

Detailed score breakdown and key findings from our analysis of 12 reviews across 2 sources.

Effectiveness How well the product works based on user reviews
80.0/100
Good
Ingredient Quality Clean label, bioavailable forms, minimal fillers
62.0/100
Average
Value for Money Price relative to quality and quantity
73.0/100
Good
Side Effects Profile Higher = fewer/milder side effects reported
60.0/100
Average
Certifications & Testing Third-party testing, GMP, and quality certifications
44.0/100
Below Average
Overall Score Weighted overall recommendation
70.0/100
Good

Pros

  • +One of the highest calorie-per-serving profiles on the market (1,258 kcal) — effective for hardgainers
  • +Strawberry flavour widely rated as pleasant, comparable to a milkshake
  • +Multiple long-term users report consistent, reliable weight and muscle gains over months to years
  • +Comprehensive formula includes creatine monohydrate, L-glutamine, and 25 vitamins and minerals
  • +Large 5.4 kg bag provides strong cost-per-serving value relative to premium competitors

Cons

  • -Predominantly maltodextrin carbohydrates — high GI, not appropriate for lean bulking or blood sugar management
  • -Full 334 g serving is very large; several users report bloating and digestive discomfort at full dose
  • -Massive scoop does not fit standard shaker bottles; blender is effectively required
  • -Not third-party tested; isolated reports of batch inconsistency in flavour and texture

Best For

Hardgainers who struggle to meet daily caloric targets through food alone Individuals with reduced appetite or difficulty eating full meals Intermediate-to-advanced trainees in a dedicated mass-gaining phase Those wanting a large-volume product from a well-established, globally recognised brand

Watch Out

  • !Digestive discomfort (bloating, gas) reported at full serving — new users should start at half dose
  • !High maltodextrin content causes rapid blood sugar spikes; unsuitable for those managing glycaemic response
  • !Contains milk, egg, soy, and wheat (gluten) — unsuitable for those with these common allergens
  • !At 1,258 kcal per serving, caloric surplus can escalate quickly without careful intake tracking

What is Serious Mass Strawberry 5.4kg?

Serious Mass Strawberry 5.4kg is a mass gainers product by Optimum Nutrition in powder form, scoring 70.0/100 on AIScored.

  • Product Overview: A high‑calorie mass gainer delivering more than 1,250 kcal and 50 g protein per serving to boost daily energy intake for muscle growth, with over 250 g carbohydrates and 3 g creatine to support performance and recovery.
  • Performance Benefits: Supplies a very high calorie load to help increase daily energy intake for weight gain 50 g blended protein per serving to support muscle growth and repair Over 250 g carbohydrates per serving to provide sustained energy for training and replenishment Contains 3 g creatine per serving and 25 vitamins and minerals to support performance and overall nutritional intake Active Ingredients That Matter: A 50 g protein blend (whey concentrate, caseinate, egg albumin) supports muscle repair; maltodextrin and other carbs supply over 250 g for calories and energy; 3 g creatine aids performance, plus L‑glutamine and 25 vitamins/minerals for recovery and micronutrient support.
  • How To Use: Add two heaped scoops (one full serving; 334 g) of Serious Mass to a blender with 710 ml of water and blend for 45–60 seconds.
  • Optionally add ice or other calorie‑contributing ingredients and blend a further 30–45 seconds.
  • For a thicker, creamier, higher‑calorie shake, mix with non‑fat or low‑fat milk instead of water.
  • New users may start with half a serving daily for the first week, then gradually increase to one or more full servings several times a day.
  • Use between meals, 30–45 minutes post‑workout to aid recovery, or 45–60 minutes before bed.
  • For best results combine with intense weight training (3–5 sessions per week) and allow at least 48 hours between workouts for the same muscle groups.
  • Best Suited For For trainees and hardgainers who require a high‑calorie, convenient supplement to support muscle growth and weight gain.
  • Always read the label.
  • This is an AI assisted summary.

What's Inside Serious Mass Strawberry 5.4kg?

Serious Mass Strawberry 5.4kg contains 46 active ingredients: Per, Of which saturates, Of which sugars, Protein and more.

Active Ingredients

Per
334g: Energy 5269kJ / 1258kcal
Of which saturates
1.6g
Of which sugars
21.8g
Protein
53.1g
Total Carbohydrate
251.5g
Total Fat
4.4g
Of which trans fats
0g
Dietary fibre
0g
Sodium
547mg
Vitamin A
299.3mcg
Vitamin D
1.9mcg
Vitamin E
3.5mg
Vitamin C
21.9mg
Folic Acid
71.3mg
Biotin
54.8mcg
Potassium
1012.5mg
Chloride
649mg
Calcium
355.7mg
Phosphorus
130.7mg
Magnesium
56.8mg
Iron
4.3mg
Zinc
2.7mg
Copper
0.5mg
Manganese
0.6mg
Selenium
42.6mcg
Chromium
130.4mcg
Iodine
50.8mcg
Creatine Monohydrate
1g
L-Glutamine
501mg
Glutamine Peptides
501mg
Choline Bitartrate
607.9mg
Inositol
250.5mg Macro Nutrient table: Energy Kcal per 100g 377Kcal
Energy kJ per
100g 1578kJ
Fats per
100g 1.3g
Of which Saturates per
100g 1g
Carbohydrates per
100g 75.4g
Sugar per
100g 6.5g
Protein per
100g 15.9g
Salt per
100g 0.16g
Fats per serving
4.4g
Of which Saturates per serving
3.4g
Carbohydrates per serving
251g
Sugar per serving
21.8g
Protein per serving
53.1g
Salt per serving
0.547g
Serving size
334g

Other Ingredients

Maltodextrin, Protein Blend (Whey Protein (Milk) Concentrate, Calcium Caseinate (Milk), Egg Albumen, Sweet Dairy Whey), Cocoa (Processed with Alkali), Natural and Artficial Flavour, Vitamin and Mineral Blend (diPotassium Phosphate, Magnesium Aspartate, diCalcium Phosphate, Calcium Citrate, Ascorbic Acid, Niacinamide, Zinc Citrate, Beta Carotene, d-Calcium Pantothenate, d-alpha Tocopheryl Succinate, Selenomethionine, Copper Gluconate, Ferrous Fumerate, Manganese Amino Acid Chelate,

Allergens: Milk, Soy, Egg, Wheat (Gluten)

Is Serious Mass Strawberry 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 Strawberry 5.4kg Compare?

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

Product Score Price
Serious Mass Strawberry 5.4kg (this) 70.0 £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 Strawberry 5.4kg worth buying in 2026?
Serious Mass Strawberry 5.4kg scores 70.0/100 in our analysis, based on 12 reviews. Optimum Nutrition Serious Mass is a long-established, high-calorie mass gainer delivering 1,258 kcal and 53 g of blended protein per 334 g serving — one of the largest single-serve calorie loads commercially available. The majority of reviewers repor...
What is the best price for Serious Mass Strawberry 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 Strawberry 5.4kg?
Pros: One of the highest calorie-per-serving profiles on the market (1,258 kcal) — effective for hardgainers. Strawberry flavour widely rated as pleasant, comparable to a milkshake. Multiple long-term users report consistent, reliable weight and muscle gains over months to years. Cons: Predominantly maltodextrin carbohydrates — high GI, not appropriate for lean bulking or blood sugar management. Full 334 g serving is very large; several users report bloating and digestive discomfort at full dose. Massive scoop does not fit standard shaker bottles; blender is effectively required.
Is Serious Mass Strawberry 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 Strawberry 5.4kg compare to Critical Mass Professional Lean Mass Gainer Banana 2.4kg (16 Servings)?
Serious Mass Strawberry 5.4kg scores 70.0/100 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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