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The Study

Nutritional Supplements for Muscle Hypertrophy: Mechanisms and Morphology—Focused Evidence

In simple terms

This study didn't do any new experiments—it just looked at what other studies found and tried to make sense of the big picture. It says things like 'protein might help when you don't eat enough,' but it can't prove that protein actually makes muscles bigger—it just sees a pattern in other people's results.

2%

Analysis score

2/ 5

Maximum 5 for a narrative review.

Where the score came from

Reporting0
Methodology0
Publication100
Statistical77
Study type (basis of the score)
Narrative Review
Level 2a - Systematic review of cohort studies
What’s the bottom line?

Some supplements help your muscles get bigger when you lift weights, but only if you're not already eating enough protein — and only certain ones work at all.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Reviews of Cohort Studies
Level 2a
2

2 / 100

Quality score

Systematic reviews and meta-analyses of cohort studies. They sit above a single cohort study but below a single randomized trial, because the underlying evidence is still observational.

Cannot establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1A 1–2 mm muscle thickening is small but measurable — like gaining a thin coin’s width of muscle; it’s not dramatic, but it’s real hypertrophy, not just water or glycogen.
  2. 2Protein helps muscles grow 1–2 mm thicker if you eat less than 1.6g per kg of body weight daily; creatine adds 1–2 mm thickness after 8–12 weeks; HMB only helps if you're dieting or training super hard; omega-3, citrulline, and collagen don't make muscles bigger.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

Nutrients

Year

2025

Authors

Andreea Maria Mănescu, Simona Ștefania Hangu, D. Mănescu

Open Access
4 citations
Analysis v5

Related Content

Claims (10)

Assertion

Taking citrulline supplements may help improve blood flow and allow more repetitions during high-repetition, short-rest workouts, but it does not cause measurable increases in muscle size over time.

Causal
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Assertion

Taking creatine supplements leads to higher levels of creatine in muscles, improves the ability to regenerate energy during intense workouts, and over 8 to 12 weeks, allows for more total training and measurable muscle growth.

Causal
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Assertion

Taking fish oil supplements containing EPA and DHA may lead to very small or negligible gains in muscle size and strength for most people, and these changes are not large enough to be meaningful in a clinical or practical sense.

Quantitative
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Assertion

Taking collagen supplements does not help muscles grow larger if you are already consuming enough total protein and vitamin C, because collagen does not contain the right amino acids or biological mechanism to directly stimulate muscle growth.

Causal
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Assertion

Ultrasound and MRI can better detect actual muscle growth by distinguishing it from temporary changes like water retention or glycogen storage, whereas methods like DXA or BIA measure total lean mass and cannot separate these factors.

Mechanistic
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Assertion

Taking 3 grams of HMB daily may increase muscle growth in resistance-trained adults only when they are under high training stress or not consuming enough calories; in well-fed, trained individuals, it typically has little to no effect on muscle growth.

Descriptive
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Fit Body Science verdict — we translate health studies into clear verdicts backed by peer-reviewed research.

Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.