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Ar7.5
Arginine Research
Probably helps
380 peer-reviewed studies
What the evidence says
Probably helps
Arginine helped in about half (13/21) of the studies that measured an effect — promising, but not unanimous.
Most evidence is from high-quality meta-analyses and randomised trials published 1979–2026 with a typical study size of 373 participants.
Based on 380 studies · 47 meta-analyses · 314 RCTs · 27,249 total participants
Confidence
High confidence
What the studies found
13helped6unclear2didn't help· 359 more without graded effect data
By outcome
Heart & blood pressureImproves endothelial function and blood pressure via nitric oxide · 4-8 weeks
Likely helps90 studies
Therapeutic & clinical
Likely helps44 studies
Women's health
Likely helps30 studies
Wound & ulcer healing
Probably helps18 studies
Endurance & exercise performanceEnhanced blood flow and oxygen delivery · 1-2 weeks · NO precursor; modest improvements in exercise tolerance · 30-60 minutes
Probably helps16 studies
Men's vitality
Mostly mechanism / observational12 studies
Glucose & metabolic
Mostly mechanism / observational11 studies
InflammationBetter endothelial function and blood pressure · 2-4 weeks
Cholesterol & lipidsImproves endothelial function and blood pressure via nitric oxide · 4-8 weeks
Too few graded studies2 studies
Safety profile
Too few graded studies2 studies
Neuroprotection & brain aging
Too few graded studies1 study
By the numbers
Pulled from 36 studies with measurable effects
Likely real effects
78%
across studies
People studied
27k
typical study: 373 people
Strongest designs
361
47 pooled, 314 randomised
Showed benefit
57%
12/21 studies
How long studies ran
1–3 months
1
3+ months
1
Populations Studied
Men with erectile dysfunction3
Pregnant women2
Adults2
Men with mild to moderate erectile dysfunction2
Steady research
63 studies in the last 5 years · Latest meta-analysis: 2026
197920022026
1Pre-eclampsia riskMeta-AnalysisCited 3×n=2,028 · very large study2025
L-arginine may be promising for pre-eclampsia prevention and treatment, but findings should be interpreted cautiously.
Makama M et al. · BJOG : an international journal of obstetrics and gynaecology (2025)
Large benefit
← WorseNo effectBetter →
In prevention trials, L-arginine was associated with a reduced risk of pre-eclampsia (relative risk [RR] 0.52; 95% confidence interval [CI], 0.35, 0.78; low-certainty evidence, four trials) and severe pre-eclampsia (RR 0.23; 95% CI, 0.09, 0.55; low-certainty evidence, three trials).
In treatment trials, L-arginine may reduce mean systolic blood pressure (MD -5.64 mmHg; 95% CI, -10.66, -0.62; very low-certainty evidence, three trials) and fetal growth restriction (RR 0.46; 95% CI, 0.26, 0.81; low-certainty evidence, two trials).
L-arginine may be promising for pre-eclampsia prevention and treatment, but findings should be interpreted cautiously.
2Erectile function improvementMeta-AnalysisCited 4×n=1,000 · large study2024
Against a background of general ineffectiveness of most nutraceutical interventions, L-Arginine and the mix PLC + ALC appeared to be of some usefulness in improving erectile function, especially in combination with PDE5i in organic ED.
Barbonetti A et al. · The journal of sexual medicine (2024)
In patients with organic ED, the efficacy of Sildenafil and Tadalafil was significantly improved by PLC + ALC and L-Arginine, respectively.
Against a background of general ineffectiveness of most nutraceutical interventions, L-Arginine and the mix PLC + ALC appeared to be of some usefulness in improving erectile function, especially in combination with PDE5i in organic ED.
3Pressure ulcer incidenceMeta-AnalysisCited 30×n=7,920 · very large study2024
The benefits of nutritional interventions with various compositions for pressure ulcer prevention and treatment are uncertain.
Langer G et al. · The Cochrane database of systematic reviews (2024)
No clear effect
← WorseNo effectBetter →
Compared to standard diet, protein supplements may result in little to no difference in pressure ulcer incidence (protein 21 per 1000, standard diet 28 per 1000; RR 0.75, 95% CI 0.49 to 1.14; 4 studies, 4264 participants; low-certainty evidence).
The evidence is very uncertain about the gastrointestinal side effects of these supplements (protein 109 per 1000, standard diet 155 per 1000; RR 0.70, 95% CI 0.06 to 7.96; 2 studies, 140 participants, very low-certainty evidence).
Compared to standard diet, energy, protein and micronutrient supplements may slightly increase the number of healed pressure ulcers (energy, protein and micronutrients 366 per 1000, standard diet 253 per 1000; RR 1.45, 95% CI 1.14 to 1.85; 3 studies, 577 participants, low-certainty evidence).
4Tumor necrosis factor-α reductionMeta-AnalysisCited 17×n=2,841 · very large study2023
Future well-designed RCTs are needed to further confirm these findings.
Ye J et al. · Nutrients (2023)
Noticeable benefit
← WorseNo effectBetter →
Glutamine was superior in decreasing tumor necrosis factor-α (MD -25.2; 95% CrI [-32.62, -17.95]), whereas combined omega-3 and arginine supplementation was more effective in decreasing interleukin-6 (MD -61.41; 95% CrI [-97.85, -24.85]).
No nutritional supplements significantly maintained nutritional indicators in CRC patients.
Future well-designed RCTs are needed to further confirm these findings.
5Total postoperative complicationsMeta-AnalysisCited 36×n=4,825 · very large study2024
Nutritional intervention with perioperative immunonutrition in patients with HAN and GI cancers significantly reduced total postoperative complications and infectious complications.
Matsui R et al. · Annals of surgery (2024)
Noticeable benefit
← WorseNo effectBetter →
Immunonutrition reduced the total postoperative complications (relative risk ratio: 0.78; 95% CI, 0.66-0.93; certainty of evidence: high) and infectious complications (relative risk ratio: 0.71; 95% CI, 0.61-0.82; certainty of evidence: high) compared with standard nutritional therapy.
The pooled analysis demonstrated significant decreases in SBP (WMD = -6.40 mmHg; 95% CI: -8.74, -4.05; P < 0.001) and DBP (WMD = -2.64 mmHg; 95% CI: -3.94, -1.40; P < 0.001) after l-arginine supplementation.
Shiraseb F et al. · Advances in Nutrition (2022)
Noticeable benefit
← WorseNo effectBetter →
Likely real
Twenty-two RCTs with 30 effect sizes were included in this meta-analysis.
The pooled analysis demonstrated significant decreases in SBP (WMD = -6.40 mmHg; 95% CI: -8.74, -4.05; P < 0.001) and DBP (WMD = -2.64 mmHg; 95% CI: -3.94, -1.40; P < 0.001) after l-arginine supplementation.
Subgroup analysis showed significant reductions in SBP and DBP regardless of baseline BP category, study duration, sex, health status, and BMI.