The Study
Eight weeks of resistance training in conjunction with glutathione and L-Citrulline supplementation increases lean mass and has no adverse effects on blood clinical safety markers in resistance-trained males
This study is like a fair test where some guys took a supplement and others didn’t, and then they all lifted weights. It found that the supplement group gained a little more muscle after 4 weeks, but not after 8 weeks. So it doesn’t prove the supplement always works—it just hints it might help for a short time.
Analysis score
Maximum 45 for a randomized controlled trial.
Where the score came from
Scientists tested if taking glutathione and L-citrulline together while lifting weights helps people gain muscle faster than taking a sugar pill.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 545 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1The muscle gain was small and temporary — it didn’t last beyond 4 weeks, so it’s unlikely to matter much for long-term training goals.
- 2After 4 weeks, the supplement group gained a bit more muscle than the placebo group — but by 8 weeks, everyone was the same.
- 3Only the supplement group showed a link between muscle gain and strength gain.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Journal of the International Society of Sports Nutrition
Year
2018
Authors
Paul S. Hwang, Flor E. Morales Marroquín, Josh Gann, Thomas L. Andre, Sarah K. McKinley-Barnard, Caelin S. Kim, M. Morita, D. Willoughby
Related Content
Claims (5)
Taking glutathione and L-citrulline supplements for 8 weeks does not change clinical blood markers in men who train with weights, indicating no detectable toxicity at this dose and duration.
In men who already train with weights, doing only resistance training for 8 weeks increases how much weight they can lift on the leg press but does not change how much weight they can lift on the bench press.
In men who regularly lift weights, taking 200 mg of glutathione and 2 g of L-citrulline daily for 4 weeks along with training is linked to a measurable increase in lean body mass compared to a placebo, but this increase does not remain after 8 weeks.
In men who train with weights, those who take glutathione and L-citrulline for four weeks show a consistent relationship between gains in lean mass and gains in muscle strength, but this relationship does not occur in those who take a placebo or L-citrulline-malate.
In resistance-trained males, taking L-citrulline-malate for 8 weeks while doing resistance training results in no significant difference in lean mass compared to taking a placebo.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.