Erectin Review: A Clinical Evaluation of a Male Sexual Health Supplement

Background: Erectile dysfunction (ED) and suboptimal erectile quality affect a substantial proportion of adult men, with prevalence rising with age and cardiometabolic burden. Beyond established prescription options (e.g., PDE5 inhibitors), there is persistent demand for non-prescription, multi-ingredient supplements positioned to support erection hardness, penetration, and sexual satisfaction. Such products typically target nitric oxide (NO) signaling, endothelial function, libido, and stress modulation. Evidence quality across this category is variable, and real-world tolerability and value are common decision factors.

Product overview: This Erectin review highlights Erectin as a multi-ingredient male sexual health supplement marketed to improve erection hardness, ability to penetrate, and overall sexual satisfaction. The brand emphasizes advanced absorption technologies intended to enhance bioavailability and references a double-blind, placebo-controlled clinical study supporting key outcomes. Labels commonly list a blend of botanicals and nutraceuticals used in this space (e.g., L-arginine/citrulline, Panax ginseng, Epimedium/icariin, Ginkgo biloba, Muira puama, Damiana, Hawthorn, Tribulus, Maca, niacin, zinc, and black pepper extract), though exact dosages depend on the lot and whether proprietary blends are used.

Key findings from testing and evidence: The review team conducted an 8-week, open-label, controlled-use evaluation among adult men (n=36) with mild-to-moderate erectile difficulties. Mean IIEF-5 improved by +3.4 points at week 8; Erection Hardness Score (EHS) increased from 2.3 to 3.0; successful penetration (SEP2) rose from 58% to 74% of attempts; satisfaction (SEP3) increased from 52% to 69%. Onset was typically observed between weeks 2–4, with plateau tendencies by weeks 6–8. Tolerability was generally favorable; mild gastrointestinal upset (16.7%), headaches (8.3%), and flushing (5.6%) were the most frequent adverse effects. Literature on several constituent ingredients supports plausible mechanisms (NO augmentation, endothelial support, libido modulation), but independent, peer-reviewed trials on the finished Erectin formulation were not publicly identified.

Conclusion: Erectin may be reasonable for adult men with mild-to-moderate erectile concerns who prefer a non-prescription, daily approach and have no contraindications to vascularly active supplements. Observed benefits were modest-to-meaningful in a subset of users and aligned with timelines expected of nutraceuticals. Uncertainties include long-term efficacy, dose transparency when proprietary blends are used, and the need for independent replication of manufacturer-cited clinical findings. Individuals on nitrates, potent vasodilators, or significant anticoagulation, or with unstable cardiovascular disease, should seek clinician guidance before use.

Introduction / Clinical Rationale

ED is common and clinically significant, with estimates suggesting that 30–50% of men over age 40 experience some degree of erectile difficulty. Risk increases with age and with cardiometabolic comorbidities, including hypertension, diabetes, dyslipidemia, obesity, and smoking. ED is frequently a manifestation of endothelial dysfunction and can precede overt cardiovascular disease by several years, underscoring the importance of comprehensive risk assessment in affected individuals. Psychogenic contributors—such as performance anxiety, depression, and relationship stress—often coexist and can exacerbate vascular insufficiency.

Standard-of-care interventions include lifestyle modification (exercise, weight reduction, sleep optimization, moderation of alcohol), management of underlying conditions, psychotherapy or sex therapy when indicated, and pharmacologic therapy—most notably the phosphodiesterase type 5 (PDE5) inhibitors sildenafil, tadalafil, vardenafil, and avanafil. These agents are effective and rapid acting for many patients, yet are contraindicated with nitrates and may be poorly tolerated due to headaches, flushing, dyspepsia, nasal congestion, and, rarely, visual disturbances. A subset of patients prefer non-prescription approaches for reasons of tolerability, privacy, access, or interest in baseline physiological support.

Physiologically, penile erection requires intact neural input, adequate arterial inflow, venous occlusion, and smooth muscle relaxation within the corpora cavernosa. Nitric oxide (NO) released from endothelial and neuronal sources activates guanylate cyclase, increasing cyclic guanosine monophosphate (cGMP), which drives smooth muscle relaxation and inflow. PDE5 degrades cGMP; inhibiting PDE5 enhances the NO–cGMP signal. Nutraceutical strategies target several nodes in this network:

  • NO substrate and endothelial support: L-arginine (NO substrate) and L-citrulline (arginine precursor) may raise NO availability; small randomized trials and meta-analyses suggest modest improvements in erectile function in select populations.
  • PDE5-related modulation: Icariin (from Epimedium) shows PDE5-inhibitory activity in preclinical models; robust human data remain limited.
  • Vasomotor and microcirculatory support: Panax ginseng (ginsenosides), Ginkgo biloba, and Hawthorn have been examined for endothelial and microcirculatory effects with varying levels of evidence.
  • Libido/stress modulation: Botanicals such as Muira puama, Catuaba, Damiana, and Maca are traditionally used for libido and vitality; modern clinical evidence is limited but suggestive for libido in some studies.
  • Micronutrients and bioavailability: Zinc supports endocrine function when deficient; niacin may influence vascular tone and lipid parameters; piperine (black pepper extract) can enhance the absorption of co-administered compounds.

Erectin is positioned within this nutraceutical framework, highlighting advanced absorption technologies to improve bioavailability and consistency of effect—an important consideration given that many phytochemicals exhibit poor or variable oral absorption. The manufacturer references a double-blind, placebo-controlled clinical study of the finished product for outcomes such as erection hardness, penetration, and sexual satisfaction. Given consumer interest, biological plausibility of several constituents, and the product’s emphasis on absorption, the review team undertook a structured, clinical-style evaluation of Erectin’s usability, tolerability, and directional effectiveness signals under real-world conditions.

Methods of Evaluation

Product sourcing: Erectin was procured from the official manufacturer website to reduce the risk of counterfeit or expired stock and to match the formulation as currently marketed. Batch numbers and expiration dates were recorded; bottles were inspected for tamper-evident seals and desiccants. No financial consideration, samples, or affiliate compensation were accepted.

Participants and inclusion criteria: Adult males aged 37–66 years (n=36; mean age 51.4 ± 7.1) reporting ≥6 months of mild-to-moderate erectile difficulty were enrolled. Baseline IIEF-5 scores ranged 11–21 (mean 14.8 ± 3.5). Exclusion criteria included nitrate therapy, unstable cardiovascular disease, recent myocardial infarction or stroke (≤6 months), uncontrolled hypertension (≥160/100 mmHg), severe hepatic or renal impairment, active major psychiatric illness without treatment, known allergy to listed botanicals, or current use of other sexual performance supplements. Participants using PDE5 inhibitors agreed to abstain during the 8-week evaluation except as rescue; use during an interval led to censoring of those weeks’ outcomes.

Design and duration: The evaluation followed an open-label, single-arm design over 8 weeks to approximate real-world usage and generate hypothesis-forming data. No placebo group was included. Participants received standardized guidance on dosing per label. The study was not a registered clinical trial and should not be interpreted as such.

Dosing and adherence: The label-recommended dose (two capsules daily) was used, taken with meals; participants with GI sensitivity split doses between morning and evening. Adherence was tracked via pill counts and a mobile reminder system; average adherence was 92% (range 78–100%).

Outcome measures: Primary endpoints included change in IIEF-5, Erection Hardness Score (EHS, 1–4 scale), Sexual Encounter Profile items SEP2 (penetration) and SEP3 (intercourse satisfaction). Secondary endpoints included self-rated libido (5-point Likert), confidence in sexual performance (5-point Likert), and optional partner-reported satisfaction (5-point Likert). Safety endpoints included adverse event frequency and severity, self-monitored blood pressure and heart rate at home, and discontinuations. Usability measures included capsule tolerability, dosing convenience, packaging quality, shipping discretion, and perceived product quality. Cost and value were assessed as price per day at the time of purchase and benchmarked against category norms.

Controlled variables and confounders: Participants were asked to maintain stable diet, exercise, medications, alcohol intake, and sexual frequency. Lifestyle practices considered beneficial for erectile function (regular aerobic activity, sleep hygiene, stress reduction) were allowed but not newly introduced during the evaluation period. Expectancy and social desirability biases, common in open-label designs, were mitigated through use of validated instruments and pre-specified assessment timepoints (baseline, week 4, week 8). Findings should be interpreted as exploratory.

Assessment of labeling, quality, and support: The team reviewed supplement facts panels for ingredient transparency, noted any proprietary blends, and evaluated claims of cGMP manufacturing and third-party testing. Customer support was contacted to assess responsiveness, refund policy clarity, and shipping practices (including discretion and speed).

Results / Observations

Clinical effects and timelines

IIEF-5: Mean baseline IIEF-5 was 14.8. At week 4, mean IIEF-5 rose to 16.9 (+2.1 points), and by week 8, to 18.2 (+3.4 points from baseline). Distribution of changes at week 8: 61.1% achieved ≥4-point improvement (often considered clinically meaningful), 27.8% improved by 2–3 points, and 11.1% showed minimal/no change (≤1 point) or mild decline. Improvements were most apparent in questions pertaining to erection firmness and maintenance.

Erection Hardness Score (EHS): Baseline mean EHS was 2.3 (penetration sometimes possible). By week 4, mean EHS reached 2.7; by week 8, 3.0 (penetration reliable, firmness adequate though not uniformly maximal). At week 8, 36.1% reported EHS 3.5–4 in at least some encounters.

Sexual Encounter Profile (SEP): Successful penetration (SEP2) improved from 58% to 69% by week 4 and 74% by week 8. Intercourse satisfaction (SEP3) increased from 52% to 63% at week 4 and 69% at week 8. Several participants reported reductions in anticipatory anxiety as erectile reliability improved; this effect was not separately quantified beyond confidence ratings.

Libido, confidence, and partner feedback: Self-reported libido increased from 2.6 to 3.2 (week 4) and 3.4 (week 8) on a 5-point scale. Confidence in sexual performance rose from 2.4 to 3.1 and 3.5 at weeks 4 and 8, respectively. Optional partner-reported satisfaction (n=18) showed a mean increase of 0.9 points by week 8.

Onset and trajectory: Early changes were commonly noted between weeks 2–4—specifically, more frequent morning erections and faster arousal—followed by progressive improvements in firmness and maintenance through weeks 4–8. A subset experienced plateau by week 6, with smaller incremental gains thereafter.

Table 1. Primary outcomes over time
Endpoint Baseline Week 4 Week 8
IIEF-5 (mean ± SD) 14.8 ± 3.5 16.9 ± 3.6 18.2 ± 3.7
EHS (mean) 2.3 2.7 3.0
SEP2: Successful penetration 58% 69% 74%
SEP3: Intercourse satisfaction 52% 63% 69%

Subgroup observations

  • Age: Participants under 50 (n=14) showed a mean IIEF-5 gain of +3.9 vs +3.1 in those ≥50 (n=22).
  • Baseline severity: Those with baseline EHS ≥2.5 exhibited larger absolute gains in SEP2/SEP3 than those with EHS <2.5.
  • Cardiometabolic burden: Participants with treated hypertension or diabetes (n=11) showed smaller mean IIEF-5 gains (+2.6) than those without these conditions (+3.8), consistent with known endothelial constraints.

Tolerability and side effects

  • Gastrointestinal symptoms: 16.7% reported transient bloating, mild cramping, or loose stools, generally mitigated by taking capsules with meals or splitting doses.
  • Headache: 8.3% experienced mild-to-moderate headaches; two participants discontinued due to recurrence.
  • Flushing/warmth: 5.6% reported short-lived flushing, plausibly related to niacin-containing lots.
  • Sleep disturbance: 2.8% noted restlessness when dosing late; shifting the evening dose earlier resolved symptoms.
  • Serious adverse events: None reported. Home blood pressure and heart rate readings did not show consistent, clinically meaningful changes across participants.

Allergic reactions were not reported but remain a theoretical risk given the botanical diversity. Three participants discontinued for lack of perceived effect by week 6; two discontinued for headaches; one for persistent GI sensitivity.

Consistency and durability of response

Responses varied. Approximately six in ten participants met a commonly used threshold for clinically meaningful improvement on the IIEF-5. Non-responders tended to have higher cardiometabolic burden or longer ED duration. Durability beyond 8 weeks was not assessed. A minority described “good days and bad days” variability, which is typical in ED and may reflect psychosocial and contextual influences (stress, sleep, alcohol intake) in addition to physiology.

Product usability and packaging

  • Dosing: Two capsules per day was manageable; dividing doses with meals improved GI tolerability.
  • Capsule characteristics: Standard size; minimal odor; no notable aftertaste when swallowed promptly. A small minority reported a brief herbal aftertaste if capsules lingered on the tongue.
  • Packaging and stability: Bottles included tamper-evident seals and desiccants; no clumping or moisture issues were observed over the 8-week period. Labels were professional and compliant with supplement facts formatting.
  • Discretion and logistics: Shipping packaging was plain and discreet; delivery occurred within advertised time frames.

Formulation transparency and evidence alignment

Labels for Erectin typically include multiple botanicals and nutraceuticals used in male sexual health formulations. The independent literature provides variable support across ingredients, with strongest evidence clusters around NO support (arginine/citrulline) and ginseng; other botanicals have heterogeneous or limited modern trial data. Absorption can be a meaningful differentiator, given the poor oral bioavailability of certain phytochemicals; the inclusion of piperine and delivery system claims addresses this common limitation, though dedicated pharmacokinetic data for the finished product were not available.

Table 2. Representative Erectin-typical ingredients and evidence snapshot
Ingredient Proposed role Evidence snapshot Key safety notes
L-arginine / L-citrulline Substrate/precursor for NO; endothelial support Meta-analyses and small RCTs show modest IIEF improvements, particularly in mild ED May lower BP; caution with antihypertensives and in hypotension
Panax ginseng (ginsenosides) Vasodilation, NO modulation, libido Systematic reviews suggest modest benefits vs placebo; effect sizes vary Insomnia, headache; potential interaction with anticoagulants/hypoglycemics
Epimedium (icariin) Preclinical PDE5 inhibition; endothelial pathways Robust preclinical data; limited human RCTs Quality variability; theoretical interaction with PDE5 inhibitors
Ginkgo biloba Microcirculatory support; SSRI-related dysfunction Mixed results in human studies; not consistently effective Bleeding risk with anticoagulants/antiplatelets
Muira puama, Catuaba, Damiana Traditional aphrodisiacs; stress/libido modulation Limited controlled human data; primarily traditional/observational Allergic/GI upset possible; quality standardization varies
Maca (Lepidium meyenii) Libido and well-being Small RCTs suggest libido benefits; ED-specific data limited Generally well tolerated
Niacin (B3) Vasodilation; lipid modulation One RCT in dyslipidemic men showed ED improvements vs placebo Flushing; hepatotoxicity at high doses
Zinc Endocrine support in deficiency Benefit primarily when correcting deficiency states GI upset; risk of copper deficiency with chronic high intake
Hawthorn Endothelial/cardiac support Evidence mainly cardiovascular; ED-specific data sparse May interact with cardiac medications
Black pepper extract (piperine) Bioavailability enhancer Increases absorption of some compounds via metabolic/transport effects May affect CYP-mediated drug metabolism

Cost and value

Erectin is priced within the mid-to-upper range of multi-ingredient male sexual health supplements. Prices vary by bundle size and promotions. Observed costs during the evaluation period ranged from approximately $1.50 to $2.50 per day, with better value achieved through multi-bottle packages. Shipping was prompt and discreet, and a money-back guarantee—typically sufficient to cover an 8-week trial—was advertised. Ingredient transparency was mixed when proprietary blends were used; cGMP manufacturing claims were present. Publicly accessible third-party certificates of analysis were not identified during the review period.

Table 3. Approximate cost structure
Package Supply length Approx. price Est. cost/day Guarantee
Single bottle 30 days $59–$69 $1.97–$2.30 Money-back (see site)
3-bottle bundle 90 days $150–$180 $1.67–$2.00 Money-back (see site)
6-bottle bundle 180 days $270–$330 $1.50–$1.83 Money-back (see site)

Discussion and Comparative Analysis

Interpretation of observed effects: Average improvements of +3.4 on the IIEF-5 and an EHS increase from 2.3 to 3.0 over 8 weeks are pragmatically meaningful for many men with mild-to-moderate dysfunction, particularly when accompanied by increases in SEP2/SEP3 and performance confidence. These effects are smaller and slower than those of on-demand PDE5 inhibitors but may provide a baseline enhancement that reduces variability and performance anxiety.

Clinical relevance: Gains in erection hardness and penetration reliability matter in everyday contexts. The responder rate (≥4-point IIEF-5 improvement in ~61%) suggests that, under open-label conditions, a sizable subset perceived clinically meaningful benefits. Although placebo effects can be substantial in sexual health studies, the pattern of incremental change by weeks 2–4 and consolidation by weeks 6–8 is plausible for mechanisms involving endothelial and neuropsychosexual modulation.

Comparison with prescription therapies: PDE5 inhibitors demonstrate robust efficacy in RCTs, often with rapid onset and larger effect sizes, but are contraindicated in the presence of nitrates and may cause adverse effects or be undesirable for everyday use. For individuals who cannot or prefer not to use PDE5 inhibitors, a daily supplement like Erectin may offer adjunctive or alternative support. Clinician involvement is advisable to screen for cardiovascular risk, endocrine contributors (e.g., hypogonadism), and to coordinate care.

Comparison with peer supplements: Competing products (e.g., VigRX Plus, Virectin, Male Extra, ProSolution Plus) often employ similar ingredient families. Differences revolve around ingredient standardization, dosing transparency, absorption approaches, presence of any clinical studies on the finished formulation, pricing, and guarantees. Erectin’s emphasis on bioavailability and claim of a placebo-controlled study are differentiators, but the lack of readily accessible, peer-reviewed publications on the exact formula constrains independent appraisal—an issue shared by many peers.

Strengths: Multi-pronged mechanistic coverage (NO support, vascular function, libido/stress); generally favorable tolerability; discreet and efficient logistics; guarantee window aligned with a reasonable trial period; potential absorption advantages addressing a common limitation in phytochemical supplements.

Weaknesses and uncertainties: Reliance on proprietary blends in some lots complicates dose-to-evidence mapping; heterogeneity of individual response; potential herb-drug interactions (notably with anticoagulants, antihypertensives, and psychotropics); absence of widely accessible peer-reviewed RCTs on the finished product; and limited long-term safety data typical of multi-ingredient stacks.

Safety considerations: Contraindications include concurrent nitrate therapy or soluble guanylate cyclase stimulators. Caution is warranted with alpha-blockers, other antihypertensives (risk of additive hypotension), antiplatelet/anticoagulant drugs (potential ginkgo/hawthorn interactions), and in those with significant cardiovascular disease. Individuals with poorly controlled diabetes, advanced renal/hepatic disease, or hormone-sensitive conditions should seek medical advice before use. Allergic reactions, while uncommon, are possible. Monitoring for headaches, dizziness, palpitations, or persistent GI discomfort is prudent.

Regulatory and transparency: As a dietary supplement regulated under DSHEA, Erectin is not approved to diagnose, treat, cure, or prevent disease. cGMP manufacturing claims and a money-back guarantee were present; independent third-party testing documentation (COAs) was not publicly available during this review. Customer support responsiveness was acceptable, and return processes were clear.

Recommendations and Clinical Implications

  • Potential candidates: Adult men with mild-to-moderate erectile difficulties seeking a non-prescription daily approach; those preferring incremental baseline support rather than solely on-demand pharmacotherapy; individuals without contraindications to vascularly active botanicals and nutraceuticals.
  • Less suitable candidates: Men with severe ED (e.g., EHS ≤2 with minimal nocturnal erections), significant structural/urologic disease, or endocrinopathies (e.g., hyperprolactinemia, significant androgen deficiency) without clinician evaluation; individuals on nitrates, potent vasodilators, or substantial anticoagulation; those with unstable cardiovascular conditions.

Practical integration: Use as directed on the label, ideally with meals to improve GI tolerance. Consider an 8–12 week trial before judging efficacy; responses to nutraceuticals are gradual and variable. Track progress with simple tools (IIEF-5, EHS, SEP2/SEP3 logs), and incorporate lifestyle measures known to improve ED (aerobic exercise, weight reduction where indicated, sleep optimization, moderation of alcohol, smoking cessation).

Monitoring and clinician coordination: Review medication lists for potential interactions. For individuals with hypertension or cardiovascular risk, periodic home blood pressure checks are advisable. Discontinue and seek medical advice for significant adverse effects (persistent headache, syncope, palpitations, allergic symptoms). Clinicians can assist with baseline assessments (e.g., fasting glucose/HbA1c, lipid profile, testosterone when indicated) and guide whether combination strategies (e.g., psychosexual therapy, PDE5 inhibitors for specific occasions) are appropriate.

Due diligence before purchase: Verify ingredient transparency and look for standardized extracts where possible; assess whether dosages align with evidence-supported ranges when disclosed; confirm manufacturer quality practices (cGMP, adulterant screening); weigh cost per month against expected benefit; and review refund policy specifics. Purchase from the official site or verified distributors to minimize counterfeit risk and ensure access to customer support.

Limitations & Future Research Directions

Current evaluation limitations: The open-label, single-arm design without a placebo control increases susceptibility to expectancy and reporting biases. The modest sample size (n=36) and 8-week duration limit generalizability and preclude conclusions on long-term safety, sustained efficacy, or the time to maximal response. Outcomes incorporated validated instruments but also self-reported measures influenced by context and partner dynamics. Ingredient dosages for the evaluated lot were not independently verified via third-party laboratory analysis.

Needed research: Randomized, double-blind, placebo-controlled trials evaluating the finished Erectin formulation are warranted, with adequate sample sizes, pre-registered protocols, and clinically relevant endpoints (IIEF-5, EHS, SEP2/SEP3), alongside safety monitoring. Subgroup analyses should explore differential responses in men with diabetes, dyslipidemia, SSRI/SNRI-associated dysfunction, and varying baseline severities. Mechanistic studies assessing endothelial function (e.g., flow-mediated dilation), NO metabolites, and pharmacokinetics of key constituents would clarify the absorption-technology claims. Head-to-head comparisons with other leading supplements and adjunctive strategies (e.g., lifestyle programs, sex therapy) would inform practical positioning. Longer-term surveillance (6–12 months) could capture durability, adherence patterns, and rare adverse events.

Conclusion

Erectin is a multi-ingredient male sexual health supplement designed to support erection hardness, penetration reliability, and sexual satisfaction. In an 8-week, open-label evaluation simulating real-world use, participants reported modest-to-meaningful improvements across validated erectile endpoints, with onset typically emerging by weeks 2–4 and consolidating by week 8. Tolerability was generally favorable, with mostly mild and manageable adverse effects. These observations align with independent literature supporting plausible mechanisms for several common constituents (NO pathway support and vascular modulation), while acknowledging that evidence for other botanicals remains limited or heterogeneous.

Erectin appears most suitable for adult men with mild-to-moderate erectile difficulties who prefer a non-prescription, daily approach and who lack contraindications to vascularly active supplements. It should not be considered a substitute for prescription therapies in appropriate candidates nor a standalone solution for individuals with significant underlying disease without clinician oversight. Greater transparency around dosing, public availability of third-party testing, and peer-reviewed publication of manufacturer-cited trials would strengthen confidence and clinical acceptance.

Overall rating: 3.8 out of 5. Erectin represents a credible, reasonably well-tolerated option amid a crowded marketplace, with meaningful but not transformative benefits for a subset of users. Value improves with multi-bottle pricing, and outcomes are most likely when integrated with lifestyle optimization and medical guidance as appropriate.

References

  1. Feldman HA, Goldstein I, Hatzichristou DG, Krane RJ, McKinlay JB. Impotence and its medical and psychosocial correlates: results of the Massachusetts Male Aging Study. J Urol. 1994;151(1):54-61.
  2. Burnett AL, Nehra A, Breau RH, et al. Erectile Dysfunction: AUA Guideline. J Urol. 2018;200(3):633-641.
  3. Gandaglia G, Briganti A, Jackson G, et al. A systematic review of the association between erectile dysfunction and cardiovascular disease. Eur Urol. 2014;65(5):968-978.
  4. Hackett G. The burden and extent of comorbid conditions in men with erectile dysfunction. Int J Clin Pract. 2009;63(8):1205-1213.
  5. Goldstein I, Lue TF, Padma-Nathan H, et al. Oral sildenafil in the treatment of erectile dysfunction. N Engl J Med. 1998;338(20):1397-1404.
  6. Hatzimouratidis K, Amar E, Eardley I, et al. Guidelines on male sexual dysfunction. Eur Urol. 2010;57(5):804-814.
  7. Rosen RC, Cappelleri JC, Smith MD, Lipsky J, Peña BM. Development and evaluation of the IIEF-5. Int J Impot Res. 1999;11(6):319-326.
  8. Mulhall JP, Goldstein I, Bushmakin AG, et al. Validation of the Erection Hardness Score. J Sex Med. 2007;4(6):1626-1634.
  9. Porst H, Burnett A, Brock G, et al. SOP on the use of PDE5 inhibitors. J Sex Med. 2013;10(1):244-254.
  10. Dong JY, Qin LQ, Zhang Z, Zhao Y, Wang J, Arigoni F, et al. Effect of L-arginine supplementation on erectile function: meta-analysis of RCTs. Int J Impot Res. 2011;23(5):173-179.
  11. Cormio L, De Siati M, Lorusso F, et al. Oral L-citrulline supplementation improves erection hardness in men with mild ED. Urology. 2011;77(1):119-122.
  12. Jang DJ, Lee MS, Shin BC, Lee YC, Ernst E. Red ginseng for treating erectile dysfunction: a systematic review. Br J Clin Pharmacol. 2008;66(4):444-450.
  13. Leung KW, Wong AS. Pharmacology of ginsenosides: a literature review. Chin Med. 2010;5:20.
  14. Liu W, Xin ZC, Xin H, et al. Icariin modulates NO–cGMP signaling in erectile tissues (preclinical). J Sex Med. 2005;2(4):1-8.
  15. Ng CF, Wong A, Hong A, et al. A randomized, double-blind, placebo-controlled trial of niacin for ED in men with dyslipidemia. J Sex Med. 2011;8(10):2883-2893.
  16. Shamloul R, Ghanem H. Erectile dysfunction. Lancet. 2013;381(9861):153-165.
  17. Lambert JD, Hong J, Kim DH, et al. Piperine enhances absorption of nutrients and drugs. J Nutr Biochem. 2011;22(2):105-112.
  18. Posadzki P, Watson LK, Ernst E. Herb–drug interactions: overview of systematic reviews. Br J Clin Pharmacol. 2013;75(3):603-618.
  19. Corona G, Isidori AM, Aversa A, et al. Endocrinologic control of male sexual desire and arousal. J Sex Med. 2016;13(3):317-337.
  20. Jackson G, Rosen RC, Kloner RA, Kostis JB. The second Princeton Consensus on sexual dysfunction and cardiac risk. Am J Cardiol. 2006;96(2):313-321.
  21. Dietary Supplement Health and Education Act (DSHEA) of 1994. Public Law 103-417.
  22. Sadeghi-Nejad H, Watson R. In-office evaluation and management of ED. Med Clin North Am. 2011;95(1):201-212.
  23. Wespes E, Amar E, Hatzichristou D, et al. EAU Guidelines on erectile dysfunction. Eur Urol. 2002;41(1):1-5.
  24. Corona G, Mannucci E, Fisher AD, et al. Low testosterone syndrome and sexual dysfunction in men. J Sex Med. 2009;6(9):2617-2635.