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Ar9.0
Arginine Research
Probably helpsModerate safety
36 peer-reviewed studies
What the evidence says
Probably helps
Arginine helped in about half (11/19) of the studies that measured an effect — promising, but not unanimous.
Most evidence is from high-quality meta-analyses and randomised trials published 2007–2026 with a typical study size of 578 participants.
Based on 36 studies · 27 meta-analyses · 6 RCTs · 27,887 total participants
Confidence
High
What the studies found
11helped6unclear2didn't help· 17 more without graded effect data
By outcome
Therapeutic & clinical
Likely helps10 studies
Heart & blood pressureImproves endothelial function and blood pressure via nitric oxide · 4-8 weeks
Likely helps8 studies
Endurance & exercise performanceEnhanced blood flow and oxygen delivery · 1-2 weeks · NO precursor; modest improvements in exercise tolerance · 30-60 minutes
InflammationBetter endothelial function and blood pressure · 2-4 weeks
Too few graded studies2 studies
Safety profile
Too few graded studies2 studies
Cholesterol & lipidsImproves endothelial function and blood pressure via nitric oxide · 4-8 weeks
Too few graded studies1 study
Neuroprotection & brain aging
Too few graded studies1 study
By the numbers
Pulled from 30 studies with measurable effects
Likely real effects
75%
across studies
People studied
28k
typical study: 578 people
Strongest designs
33
27 pooled, 6 randomised
Showed benefit
53%
10/19 studies
How long studies ran
1–3 months
1
3+ months
1
Populations Studied
Men with erectile dysfunction3
Men with mild to moderate erectile dysfunction2
General population2
Pregnant women1
Active research area
24 studies in the last 5 years · Latest meta-analysis: 2026
200720162026
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.
8Proportion of ulcers healedMeta-AnalysisCited 31×n=629 · large study2020
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).
9Athletic performance in soccer playersMeta-AnalysisCited 6×2025
This study suggests that a range of dietary supplements, including caffeine, creatine, creatine + sodium bicarbonate, magnesium creatine chelate, carbohydrate + electrolyte, carbohydrate + protein, arginine, beta-alanine, bovine colostrum, Kaempferia parviflora, melatonin, and sodium pyruvate, can improve athletic performance in soccer players.
Luo H et al. · Journal of the International Society of Sports Nutrition (2025)
Kaempferia parviflora (SMD: 0.46, small) was associated with a significant effect on enhancing muscular strength.
Beta-alanine (SMD: 0.83, moderate), melatonin (SMD: 0.75, moderate), caffeine (SMD: 0.37, small), and creatine (SMD: 0.33, small) were associated with a significant effect on enhancing jump height.
Magnesium creatine chelate (SMD: -3.0, very large), melatonin (SMD: -1.9, large), creatine + sodium bicarbonate (SMD: -1.4, large), and arginine (SMD: -1.2, moderate) were associated with a significant effect on decreasing sprint time.
10Erectile dysfunction improvementMeta-AnalysisCited 35×n=540 · large study2019
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.
11Sexual function in erectile dysfunctionMeta-AnalysisCited 5×n=184 · medium study2023
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.
12Pressure injury healingMeta-AnalysisCited 10×n=196 · medium study2022
Our findings suggest that the administration of Arginine supplement in patients with PIs can accelerate the healing of this type of ulcer.
Cheshmeh S et al. · Nursing open (2022)
Large benefit
← WorseNo effectBetter →
Likely real
PIs were significantly improved with Arginine supplementation (SMD: -0.6; CI 95%: -0.9 to -0.3, I2 : 72.5%, p = .001).
Subgroup analysis showed that administering Arginine supplement more than 15 g/day had more beneficial effects on the healing of PIs (SMD: -2.8; CI 95%: -4.08 to -1.52, I2 : 54.7%, p = .138).
Our findings suggest that the administration of Arginine supplement in patients with PIs can accelerate the healing of this type of ulcer.
13Sexual function improvementMeta-AnalysisCited 4×n=373 · medium study2021
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).
15Efficacy of dietary supplements for erectile dysfunctionMeta-AnalysisCited 12×2023
DSs marketed in Italy are usually blends of many substances that are frequently employed at a negligible dose or without any evidence.
Petre GC et al. · Nutrients (2023)
No clear effect
← WorseNo effectBetter →
Based on the scoring system, 2 (8%) supplements matched with the cluster of higher expected efficacy, 3 (12%) with the lower efficacy cluster and 20 (80%) matched with the criterion of no expected efficacy.
A systematic review of the literature was performed to evaluate the effect of DS and to detect the active ingredients able to improve erectile function-called effective ingredients (EIs)-and their minimal effective daily dose (mED).
A metanalysis identified some nutraceuticals, such as Panax ginseng, Tribulus terrestris and L-arginine, that are able to improve male sexual function.
This meta-analysis examined the effects of Arginine.
Zinellu A et al. · Translational psychiatry (2024)
In subgroup analysis, the pooled SMD for ornithine was significantly different in studies of untreated, but not treated, patients.
Our study suggests that DDAH1 and arginase are dysregulated in schizophrenia.
Further studies are warranted to investigate the expression/activity of these enzymes in the brain of patients with schizophrenia and the effects of targeted treatments.
Alterations in ADMA, SDMA, and citrulline, biomarkers of NO synthesis, may be useful to investigate the pathophysiology of different forms of dementia and identify novel therapeutic strategies. (PROSPERO registration number: CRD42023439528).
Zinellu A et al. · Ageing research reviews (2023)
Large benefit
← WorseNo effectBetter →
Likely real
By contrast, compared to controls, patients with dementia had significantly higher ADMA (standard mean difference, SMD=0.62, 95% CI 0.06-1.19, p = 0.029), SDMA (SMD=0.70, 95% CI 0.34-1.35, p<0.001), and citrulline concentrations (SMD=0.50, 95% CI 0.08-0.91, p = 0.018).
In subgroup analysis, the effect size was significantly associated with treatment with cholinesterase inhibitors and/or antipsychotics for ADMA, and underlying disorder (Alzheimer's disease), study continent, and analytical method for citrulline.
Alterations in ADMA, SDMA, and citrulline, biomarkers of NO synthesis, may be useful to investigate the pathophysiology of different forms of dementia and identify novel therapeutic strategies. (PROSPERO registration number: CRD42023439528).
19Hydroxyproline content in wound healingMeta-AnalysisCited 105×2021
Conclusion: The wound healing might be enhanced in one or at various stages by nutritional supplementation in the right dose.
Arribas-López E et al. · Nutrients (2021)
Noticeable benefit
← WorseNo effectBetter →
Likely real
The overall meta-analysis demonstrated a significant effect of arginine supplementation on hydroxyproline content (MD: 4.49, 95% CI: 3.54, 4.45, p < 0.00001).
Regarding T-cell lymphocytes, a slight decrease was observed, although it failed to reach significance (MD: -0.16, 95% CI: -0.33, 0.01, p = 0.07).
Conclusion: The wound healing might be enhanced in one or at various stages by nutritional supplementation in the right dose.