Endpoint
Flow-mediated dilation
CAT:outcome/flow-mediated-dilationreported in percent
Method
Percent increase in brachial artery diameter following release of a cuff occlusion (reactive hyperaemia), by high-resolution B-mode ultrasound. Cuff position, occlusion duration and whether diameter was edge-detected automatically are recorded on the edge.
The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.
Notes
"FMD" declared 2026-08-27, after a citrulline claim both extraction passes agreed on was refused with "FMD shares no vocabulary with CAT:outcome/flow-mediated-dilation". It is the near-universal abbreviation in this literature and the fourth of this exact shape after FBG, LOS and WBC. Like WBC and unlike LOS, it abbreviates the WHOLE endpoint rather than a substring two endpoints share, and no sibling contests it — the velocity and stiffness measures it is confusable with have their own names. So declaring it discriminates rather than merges. SIGN INVERSION HAZARD against pulse wave velocity and carotid-femoral pulse wave velocity, measured in the same trials (PMID 40573153 reports both): both are non-invasive vascular-function endpoints reported together, but this improves by RISING and every velocity-based arterial-stiffness measure improves by FALLING. Also distinct from muscle oxygen saturation by near-infrared spectroscopy, which is likewise a percentage from the same trial in PMID 37561087 but measures microvascular and tissue extraction rather than conduit-vessel reactivity — the two dissociated there. Distinct again from augmentation index, a pressure-waveform measure of wave reflection, and from carotid intima-media thickness, which is structure rather than function.
Findings
2 findings from 1 compound, strongest first.
L-citrulline — increases
LikelyGrade B, Likely. Human evidence, limited replication or design limits.Findingreplicated ×1“Compared to the placebo, FMD significantly increased after 4 weeks of CIT supplementation (placebo: Δ−0.7 ± 0.6% vs. CIT: Δ1.6 ± 0.7%, p < 0.05) B).”
Quoted verbatim from L-Citrulline Supplementation Improves Arterial Blood Flow and Muscle Oxygenation during Handgrip Exercise in Hypertensive Postmenopausal Women.. - Study
- RCT
- Participants
- 22
- Duration
- 4 weeks
- Dose
- L-citrulline 10 g/day (NOW Foods), taken as 4.5 g (6 capsules of 750 mg) in the morning and 5.25 g (7 capsules of 750 mg) in the evening, for 4 weeks
- Population
- Sedentary hypertensive postmenopausal women aged 50-71 years, resting systolic blood pressure at or above 130 mmHg (or 120 mmHg if on antihypertensive medication); 4 of 11 in the citrulline arm and 3 of 11 in the placebo arm were taking an antihypertensive and 1 in each arm a statin.
L-Citrulline Supplementation Improves Arterial Blood Flow and Muscle Oxygenation during Handgrip Exercise in Hypertensive Postmenopausal Women.2024PMID:38931289
L-citrulline — increases
SuggestiveGrade C, Suggestive. Weak human evidence, or strong evidence in a mismatched population.Findingreplicated ×1“FMD improved in the fasted state after CIT supplementation compared to placebo (CIT: Δ1.3 ± 0.2% vs. Placebo: Δ−0.5 ± 0.1%, p < 0.01) A).”
Quoted verbatim from Effects of L-Citrulline Supplementation on Endothelial Function, Arterial Stiffness, and Blood Glucose Level in the Fasted and Acute Hyperglycemic States in Middle-Aged and Older Adults with Type 2 Diabetes.. - Study
- crossover
- Participants
- 16
- Duration
- 4 weeks
- Dose
- 6 g/day L-citrulline as 750 mg capsules, four in the morning and four in the evening, for 4 weeks
- Population
- Middle-aged and older adults with type 2 diabetes, mean age 62 years, treated with oral hypoglycaemic drugs and/or insulin, none doing structured exercise; measured in the fasted state.