The Study
Citrulline Supplementation Improves Microvascular Function and Muscle Strength in Middle-Aged and Older Adults with Type 2 Diabetes
This study gave some people with diabetes a supplement and saw if their blood flow and leg strength got better. It’s like testing if eating a new snack makes you run faster—but only tried it on 16 people for a month. So we can say it might help, but we don’t know if it would work for everyone.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
This study tested if taking a daily amino acid called citrulline helps older people with type 2 diabetes improve blood flow to their muscles and get stronger in their legs.
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 580 / 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.
- 1Yes — better blood flow and stronger calves could mean easier walking and less risk of falls or mobility loss in older diabetics.
- 2After 4 weeks of taking 6 grams of citrulline daily: blood flow to muscles improved by 13% (LnRHI), leg strength relative to body weight went up by 0.02 kg/kg, and arginine levels in blood rose by 69%.
- 3Handgrip strength didn't change.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrients
Year
2025
Authors
Arturo Figueroa, Katherine N. Dillon, Danielle E Levitt, Yejin Kang
Related Content
Claims (6)
When citrulline is metabolized, it leads to increased nitric oxide production in blood vessel lining cells, which causes blood vessels to widen and improves oxygen delivery to skeletal muscle.
In middle-aged and older adults with well-controlled type 2 diabetes, taking 6 grams of citrulline daily for four weeks increases blood flow to small vessels by 13% and increases calf muscle strength relative to body weight by 0.02 kg per kg, and these two changes occur together.
In middle-aged and older adults with type 2 diabetes, taking 6 grams of citrulline daily for 4 weeks raises plasma arginine levels by about 69%, and this rise is linked to better blood vessel function in small vessels and stronger calf muscles.
Taking 6 grams of citrulline daily for four weeks does not improve handgrip strength in middle-aged and older adults with type 2 diabetes.
In middle-aged and older adults with type 2 diabetes, when microvascular endothelial function improves after taking citrulline, relative calf muscle strength also improves.
In middle-aged and older adults with type 2 diabetes, taking 6 grams of citrulline daily for 4 weeks increases blood flow through small vessels in the forearm muscles during a standard test of vascular response.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.