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Ar7.5
Arginine Research
Probably helps
381 peer-reviewed studies
What the evidence says
Probably helps
Arginine helped in about half (12/20) 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 203 participants.
Based on 379 studies · 42 meta-analyses · 314 RCTs · 25,884 total participants
Confidence
High confidence
What the studies found
12helped6unclear2didn'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 helps91 studies
Therapeutic & clinical
Likely helps46 studies
Women's health
Likely helps31 studies
Wound & ulcer healing
Probably helps19 studies
Endurance & exercise performanceEnhanced blood flow and oxygen delivery · 1-2 weeks · NO precursor; modest improvements in exercise tolerance · 30-60 minutes
Mostly mechanism / observational14 studies
Men's vitality
Mostly mechanism / observational12 studies
Glucose & metabolic
Mostly mechanism / observational12 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
Neuroprotection & brain aging
Too few graded studies1 study
By the numbers
Pulled from 34 studies with measurable effects
Likely real effects
78%
across studies
People studied
26k
typical study: 203 people
Strongest designs
356
42 pooled, 314 randomised
Showed benefit
55%
11/20 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
69 studies in the last 5 years · Latest meta-analysis: 2026
197920022026
1Pre-eclampsia riskMeta-Analysisn=2,028 · very large study2025
In plain English: 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.
2Total postoperative complicationsMeta-Analysisn=4,825 · very large study2024
In plain English: 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.
3Pressure ulcer incidenceMeta-Analysisn=7,920 · very large study2024
In plain English: 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).
4Erectile function improvementMeta-Analysisn=1,000 · large study2024
In plain English: 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.
5Tumor necrosis factor-α reductionMeta-Analysisn=2,841 · very large study2023
In plain English: 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.
In plain English: 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.
8Sexual function improvementMeta-Analysisn=373 · medium study2021
In plain English: Besides, PDE5Is alone revealed a better effect than those treated with L-arginine alone for patients with ED.
Xu Z et al. · Andrologia (2021)
Erectile functions were significantly improved in three therapy groups compared with baseline.
Conclusively, compared with monotherapy, the combination of L-arginine and PDE5Is showed a greater improvement of sexual function and total testosterone, and did not significantly increase the AEs.
Furthermore, patients who treated with PDE5Is alone exhibited the better efficacy than those treated with L-arginine alone in respects of sexual function index (p <0.00001) and total testosterone (p =0.0001).
9Erectile dysfunction improvementMeta-Analysisn=540 · large study2019
In plain English: The results of our systematic review and meta-analysis provide evidence on the effectiveness of arginine supplements for mild to moderate ED.
Rhim HC et al. · The journal of sexual medicine (2019)
Huge harm
← WorseNo effectBetter →
Likely real
The analysis demonstrated that arginine supplements with dosage ranging from 1,500 to 5,000 mg significantly improved ED compared with placebo or no treatment (odds ratios, 3.37 [1.29, 8.77], P = .01, I2 = 44).
Arginine supplements also caused significant improvements in the IIEF subdomain scores of overall satisfaction, intercourse satisfaction, orgasmic function, and erectile function, whereas the IIEF sexual desire score remain unchanged.
The adverse effect rate in the arginine-treated group was 8.3%, and that in the placebo group was 2.3%, none of which were severe.
15Sexual function in erectile dysfunctionMeta-Analysisn=184 · medium study2023
In plain English: These results indicate that the combination of PAL may have a significant effect on improving sexual function in patients with mild to moderate ED.
Tian Y et al. · Frontiers in endocrinology (2023)
These results indicate that the combination of PAL may have a significant effect on improving sexual function in patients with mild to moderate ED.
This study will provide clinicians with more options for treating patients with ED.
More randomized controlled trials are needed in the future to further demonstrate the effect of combination therapy on sexual function in patients with ED.
16Proportion of ulcers healedMeta-Analysisn=629 · large study2020
In plain English: Evidence for the impact of nutritional interventions on the healing of foot ulcers in people with diabetes compared with no nutritional supplementation, or compared with a different dose of nutritional supplementation, remains uncertain, with eight studies showing no clear benefit or harm.
Moore ZE et al. · The Cochrane database of systematic reviews (2020)
No clear effect
← WorseNo effectBetter →
It is also uncertain whether arginine, glutamine and β-hydroxy-β-methylbutyrate supplement increases the proportion of ulcers healed at 16 weeks compared with placebo (RR 1.09, 95% CI 0.85 to 1.40).
It is uncertain whether oral nutritional supplement with 20 g protein per 200 mL bottle, 1 kcal/mL, nutritional supplement with added vitamins, minerals and trace elements, reduces the number of deaths (RR 0.96, 95% CI 0.06 to 14.60) or amputations (RR 4.82, 95% CI 0.24 to 95.88) more than placebo.
It is uncertain whether arginine, glutamine and β-hydroxy-β-methylbutyrate supplement increases health-related quality of life at 16 weeks more than placebo (MD -0.03, 95% CI -0.09 to 0.03).