Editing Openai/6963c099-ff20-8011-adc8-8f1339cd1c1b (section)

=== Assistant: Here’s a summary of major human research on branched-chain amino acids BCAAs — focusing on the structure, findings, and… ===
Here’s a summary of major human research on branched-chain amino acids (BCAAs) — focusing on the structure, findings, and years of the studies where available. I’ve included key results and limitations from human trials, not animal work.

==== 🔬 Key Human Studies & Findings on BCAAs ====

===== 1) Early Molecular Mechanism Work — 2006 =====
* Study by Shimomura & Blomstrand (2006) Found that BCAA supplementation before exercise reduced post-exercise muscle protein breakdown and signs of muscle fatigue in humans. ScienceDirect<ref>{{cite web|title=ScienceDirect|url=https://www.sciencedirect.com/science/article/pii/S0022316622080944|publisher=sciencedirect.com|access-date=2026-01-12}}</ref>
* Blomstrand et al. (2006) Showed BCAAs activate mTOR signaling pathways in human muscle after exercise, which is linked to protein synthesis. ScienceDirect<ref>{{cite web|title=ScienceDirect|url=https://www.sciencedirect.com/science/article/pii/S0022316622080476|publisher=sciencedirect.com|access-date=2026-01-12}}</ref>

: Early mechanistic work supported the idea that BCAAs have anabolic signaling effects, but these did not directly measure long-term muscle growth.

===== 2) Human Muscle Protein Synthesis Studies — 2017 =====
* Jackman et al. (2017): Investigated sole BCAA ingestion and measured myofibrillar muscle protein synthesis (MPS). They saw a response in synthesis rates after BCAAs alone. Frontiers<ref>{{cite web|title=Frontiers|url=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00390/full|publisher=frontiersin.org|access-date=2026-01-12}}</ref>
* Wolfe review (2017): Summarized human data and intravenous infusion results — BCAA alone did not increase net muscle protein synthesis, because other essential amino acids were missing. PMC<ref>{{cite web|title=PMC|url=https://pmc.ncbi.nlm.nih.gov/articles/PMC5568273/|publisher=pmc.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>

: These studies highlighted a discrepancy: signaling pathways activate, but without complete essential amino acids, sustained muscle protein building is limited.

===== 3) Meta-Analyses on Recovery Markers — 2021 =====
* Khemtong et al. (2021): A meta-analysis of trials (2010–2020) found BCAA supplements reduce creatine kinase (CK) and muscle soreness after resistance training in trained men (markers of muscle damage), but they didn’t clearly improve performance. PMC<ref>{{cite web|title=PMC|url=https://pmc.ncbi.nlm.nih.gov/articles/PMC8230327/|publisher=pmc.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>
* Ooi et al. (2021): Looked at overweight/obese adults during weight loss and found BCAAs did not preserve lean mass or improve insulin sensitivity during calorie restriction. PubMed<ref>{{cite web|title=PubMed|url=https://pubmed.ncbi.nlm.nih.gov/33537760/|publisher=pubmed.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>

===== 4) Recent Trials & Reviews — 2024–2025 =====
* Salem et al. (2024): Review of systematic studies concluding BCAAs reduce muscle soreness and biomarkers of muscle damage but not muscle performance post-exercise. PubMed<ref>{{cite web|title=PubMed|url=https://pubmed.ncbi.nlm.nih.gov/38241335/|publisher=pubmed.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>
* Luan et al. (2025): Found that BCAA supplementation in active males enhanced fat oxidation and exercise efficiency and reduced immediate post-exercise fatigue. PubMed<ref>{{cite web|title=PubMed|url=https://pubmed.ncbi.nlm.nih.gov/40219047/|publisher=pubmed.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>
* Robbins et al. (2025): Reported BCAA may improve muscle strength and reduce soreness in older adults (e.g., sarcopenia context). MDPI<ref>{{cite web|title=MDPI|url=https://www.mdpi.com/2674-0311/4/3/32|publisher=mdpi.com|access-date=2026-01-12}}</ref>

===== 5) Broader Human Evidence Synthesis =====
* Kaspy et al. (review): BCAAs can activate pathways tied to MPS and reduce protein breakdown markers, but effects are smaller than complete protein intake. Cambridge University Press & Assessment<ref>{{cite web|title=Cambridge University Press & Assessment|url=https://www.cambridge.org/core/journals/nutrition-research-reviews/article/effects-of-branchedchain-amino-acids-on-muscle-protein-synthesis-muscle-protein-breakdown-and-associated-molecular-signalling-responses-in-humans-an-update/9912227DD5144B0F7EB06260029520D7|publisher=Cambridge University Press & Assessment|access-date=2026-01-12}}</ref>
* Reviews through 2024 (eg. Choi et al.): Explore BCAA roles beyond muscle, including metabolic regulation and aging effects in humans. Nature<ref>{{cite web|title=Nature|url=https://www.nature.com/articles/s12276-024-01263-6|publisher=nature.com|access-date=2026-01-12}}</ref>

==== 📌 What the Evidence Shows (Human-Level) ====

| Outcome                                  | Evidence strength   | Examples                                                                                    |
| ---------------------------------------- | ------------------- | ------------------------------------------------------------------------------------------- |
| Muscle protein synthesis (MPS)           | Limited/conditional | BCAAs activate anabolic signaling, but sustained MPS requires other EAAs. 
PMC
+1           |
| Muscle soreness/damage markers           | Moderate            | Meta-analyses show reduced CK and soreness with BCAA. 
PMC                                  |
| Muscle performance/strength              | Weak/inconsistent   | Some recent studies in older adults suggest benefit; not robustly consistent overall. 
MDPI |
| Lean mass preservation in weight loss    | No clear benefit    | 2021 trial showed no lean mass preservation. 
PubMed                                        |
| Fat oxidation/efficiency during exercise | Emerging evidence   | 2025 study found increased fat oxidation and reduced fatigue. 
PubMed                       |

==== 🧠 What Researchers Commonly Note ====
* Mechanistic effects (mTOR activation) are clear, but physiological outcomes depend on context (dietary protein, exercise type). ScienceDirect<ref>{{cite web|title=ScienceDirect|url=https://www.sciencedirect.com/science/article/pii/S0022316622080476|publisher=sciencedirect.com|access-date=2026-01-12}}</ref>
* Isolated BCAAs are less effective than complete essential amino acid mixes or whole protein sources for meaningful muscle building. Cambridge University Press & Assessment<ref>{{cite web|title=Cambridge University Press & Assessment|url=https://www.cambridge.org/core/journals/nutrition-research-reviews/article/effects-of-branchedchain-amino-acids-on-muscle-protein-synthesis-muscle-protein-breakdown-and-associated-molecular-signalling-responses-in-humans-an-update/9912227DD5144B0F7EB06260029520D7|publisher=Cambridge University Press & Assessment|access-date=2026-01-12}}</ref>
* Benefits are more likely seen in recovery markers (soreness, CK) than actual long-term muscle hypertrophy. PubMed<ref>{{cite web|title=PubMed|url=https://pubmed.ncbi.nlm.nih.gov/38241335/|publisher=pubmed.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>

==== 📅 Timeline of Key Human BCAA Research ====
* 2006: Early mechanistic studies on BCAA effects in human muscle after exercise. ScienceDirect<ref>{{cite web|title=ScienceDirect|url=https://www.sciencedirect.com/science/article/pii/S0022316622080944|publisher=sciencedirect.com|access-date=2026-01-12}}</ref>
* 2017: Controlled trials on BCAA ingestion and muscle protein synthesis. PMC<ref>{{cite web|title=PMC|url=https://pmc.ncbi.nlm.nih.gov/articles/PMC5568273/|publisher=pmc.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>
* 2021: Meta-analyses show recovery effects but limited lean mass benefits. PubMed<ref>{{cite web|title=PubMed|url=https://pubmed.ncbi.nlm.nih.gov/33537760/|publisher=pubmed.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>
* 2024–2025: Newer work explores exercise efficiency, fat oxidation, aging/sarcopenia contexts. PubMed<ref>{{cite web|title=PubMed|url=https://pubmed.ncbi.nlm.nih.gov/40219047/|publisher=pubmed.ncbi.nlm.nih.gov|access-date=2026-01-12}}</ref>

If you want, I can list specific study designs, sample sizes, and numerical results for a few of these trials.