Research
Hormonal
Protein and essential amino acid (EAA) supplementation promotes measurable muscle hypertrophy (via ultrasound/MRI) only when daily intake is below 1.6 g/kg/day or per-meal leucine is below 2–3 g; benefits plateau once these thresholds are met.
If you already eat enough protein (around 1.6g per kg of body weight) or get enough leucine per meal (2-3g), adding more protein powder will not make your muscles grow bigger. Focus on hitting that baseline first; extra protein is wasted for hypertrophy purposes.
GoodConditionalHIGH confidence
protein/essential amino acids (EAA) showed consistent benefits when daily intake was <1.6 g·kg−1·day−1 or when per-meal leucine provision was <2–3 g; effects plateaued once intakes exceeded ~2.0 g·kg−1·day−1.
Why this rating
Based on 46 eligible trials using morphology-direct endpoints (ultrasound/MRI), though the review is narrative.
Source
Nutritional Supplements for Muscle Hypertrophy: Mechanisms and Morphology—Focused Evidence
Andreea Maria Mănescu et al. · Nutrients · 2025
DOI 10.3390/nu17223603
narrative_review
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
More from this paper
- Creatine monohydrate (3–5 g/day) increases muscle thickness and cross-sectional area in resistance training interventions lasting 8–12 weeks or more, primarily by enabling higher training volume and quality rather than direct anabolic signaling.Good
- β-hydroxy-β-methylbutyrate (HMB, 3 g/day) has conditional utility for muscle hypertrophy, showing benefits primarily during high training stress or caloric deficits, but is largely neutral in well-fed, resistance-trained individuals.Moderate
- Adjunct supplements (omega-3 fatty acids, citrulline, collagen) facilitate training tolerance, recovery, or connective-tissue adaptation but do not directly drive muscle hypertrophy.Moderate
Related findings · Hormonal
- Initial treatment for type 2 diabetes should be a combination of metformin and either an SGLT-2 inhibitor or a GLP-1 receptor agonist to achieve cardiorenal protection, rather than monotherapy or older agents like sulfonylureas.Strong
- For patients with specific monogenic obesity syndromes (leptin deficiency, POMC/PCSK1/LEPR mutations), targeted pharmacotherapy (recombinant leptin or setmelanotide) is highly effective and should be prioritized, unlike in polygenic obesity.Strong
- Continued weekly administration of 2.4 mg subcutaneous semaglutide prevents weight regain and promotes further weight loss in adults with overweight or obesity, whereas switching to placebo results in significant weight regain.Strong
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →