Testosterone and Erectile Function: The Complete Clinical Guide to Natural Boosters vs. Medical Treatment

Testosterone and Erectile Function: The Complete Clinical Guide to Natural Boosters vs. Medical Treatment

By Arsenal Men's Health Clinical Team  •  Medically Reviewed by Courtney LaSumner Bass, NP

Reading Time: 12 minutes  |  Last Updated: December 2025  |  Evidence-Based Clinical Review

Key Takeaway: While natural testosterone boosters like ashwagandha and fenugreek show promising research for mild hormonal support, they cannot replace clinician-supervised testosterone replacement therapy (TRT) for men with clinically diagnosed hypogonadism. If you're experiencing erectile dysfunction, a comprehensive evaluation by a licensed provider is essential for identifying the true underlying cause and developing an effective treatment plan.

Understanding the Testosterone-Erectile Function Connection

When men experience difficulties achieving or maintaining erections, there's often an instinctive concern about testosterone levels. This concern isn't unfounded—testosterone plays a crucial role in male sexual function—but the relationship between testosterone and erectile dysfunction (ED) is more nuanced than most men realize.

The Massachusetts Male Aging Study, one of the most comprehensive investigations into male sexual health, found that approximately 52% of men between ages 40-70 experience some degree of erectile dysfunction. Research indicates that nearly 30% of men under 40 may also experience ED at some point. These numbers underscore an important truth: sexual performance challenges are extraordinarily common and should never be a source of shame.

Here's what the clinical evidence tells us: erectile dysfunction is primarily a vascular condition, not a hormonal one. An erection results from complex coordination between psychological arousal, neural signaling, and blood flow to penile tissue. Testosterone influences this process, but it's typically not the primary driver of erectile function.

The Science: How Testosterone Influences Erections

The Nitric Oxide Pathway

Research published in The Journal of Clinical Hypertension identifies nitric oxide (NO) as the primary biochemical mediator of erectile function. Released by nerve and endothelial cells in the corpora cavernosa, NO activates a signaling cascade that ultimately relaxes the smooth muscle tissue in the penis, allowing increased blood flow and engorgement.

A landmark study published in the International Journal of Impotence Research demonstrated that testosterone plays a critical role in regulating nitric oxide synthase (NOS)—the enzyme responsible for producing nitric oxide. In castrated animal models, researchers observed:

• Rapid decrease in intracavernous pressure following testosterone depletion

• Decreased density of NOS-containing nerve fibers proportional to time since castration

• Near-complete restoration of erectile response with testosterone replacement

More recent human research published in Andrology (2020) confirmed these findings in human corpus cavernosum tissue, showing that testosterone positively regulates both endothelial NOS (eNOS) and neuronal NOS (nNOS) expression, while simultaneously inhibiting phosphodiesterase type 5 (PDE5)—the enzyme that breaks down the signaling molecules responsible for maintaining erections.

Why Low Testosterone Doesn't Always Mean ED

Despite testosterone's influence on erectile physiology, clinical evidence reveals an important distinction: many men with low testosterone levels maintain normal erectile function, while men with healthy testosterone levels may still experience ED.

According to research published in Sexual Medicine Reviews (2019), testosterone deficiency induces endothelial dysfunction through multiple mechanisms—including reduced NO bioavailability, increased asymmetric dimethylarginine (ADMA, an endogenous NO inhibitor), and impaired endothelial progenitor cell function. However, these effects typically manifest when testosterone levels fall significantly below the normal physiological range.

The clinical takeaway: ED has multiple potential causes—cardiovascular disease, diabetes, neurological conditions, psychological factors, medication side effects, and hormonal imbalances. Assuming low testosterone is responsible without proper evaluation may delay appropriate treatment.

Natural Testosterone Boosters: What the Research Actually Shows

The supplement industry promotes numerous "natural testosterone boosters" as alternatives to medical treatment. Let's examine what peer-reviewed research actually reveals about the most popular options.

Ashwagandha (Withania somnifera)

Evidence Level: Moderate

Ashwagandha is among the most well-researched natural testosterone-supporting compounds. A 2022 randomized, double-blind, placebo-controlled trial published in Health Science Reports demonstrated that 600mg daily of standardized ashwagandha root extract over 8 weeks produced:

• 88.5% greater probability of improving overall sexual function scores compared to placebo

• Significant improvements in sexual cognition, arousal, orgasm, and desire

• Increased serum testosterone levels

• Decreased serum prolactin (which can suppress testosterone production)

A 2019 crossover study published in Evidence-Based Complementary and Alternative Medicine found that ashwagandha supplementation in overweight men aged 40-70 was associated with 15% higher salivary testosterone and 18% higher DHEA-S levels compared to placebo. Additional research in oligospermic men showed a 167% increase in sperm count and 17% increase in serum testosterone after 90 days of supplementation.

Mechanism: Ashwagandha appears to function as an adaptogen, modulating the hypothalamic-pituitary-adrenal (HPA) axis and reducing cortisol—a stress hormone that can suppress testosterone production. Its withanolide glycosides may also support steroid hormone biosynthesis pathways.

Fenugreek (Trigonella foenum-graecum)

Evidence Level: Moderate

A 2020 meta-analysis published in Phytotherapy Research evaluated four randomized clinical trials and concluded that fenugreek extract has a statistically significant effect on total serum testosterone levels in men.

A notable 2016 randomized controlled pilot study published in the Journal of Sport and Health Science found that fenugreek glycoside supplementation during resistance training produced significant increases in free testosterone without reduction in total testosterone, along with improvements in body fat composition.

Mechanism: Fenugreek contains diosgenin, a precursor for sex hormone synthesis. Research suggests it may inhibit aromatase (which converts testosterone to estrogen) and 5-alpha reductase (which converts testosterone to DHT), thereby maintaining higher free testosterone levels.

Vitamin D

Evidence Level: Mixed

The relationship between vitamin D and testosterone presents conflicting evidence. A 2011 study in Hormone and Metabolic Research found that vitamin D-deficient men who supplemented experienced significant increases in total testosterone (10.7 → 13.4 nmol/L), bioactive testosterone, and free testosterone over 12 months.

However, a 2019 meta-analysis published in the Journal of Steroid Biochemistry and Molecular Biology evaluating eight randomized controlled trials concluded that vitamin D supplementation had no significant effect on total testosterone or SHBG in most men. The exception appears to be men who are truly vitamin D deficient—in these individuals, correcting the deficiency may support testosterone levels.

Clinical Significance: Given Utah's northern latitude and indoor lifestyles, many men in our patient population are vitamin D insufficient. Testing and appropriate supplementation may provide benefits beyond testosterone support, including bone health and immune function.

Zinc

Evidence Level: Established for Deficiency

A comprehensive review published in The Aging Male (2019) examined clinical trials from 1977-2018 and found consistent evidence that zinc supplementation increases serum testosterone in zinc-deficient men. Zinc is essential for testosterone synthesis and is concentrated in the testes.

Important Caveat: Zinc supplementation is only effective in men who are deficient. Taking zinc when you have adequate levels is unlikely to provide additional testosterone-boosting benefits and may cause gastrointestinal side effects or interfere with copper absorption.

Other Popular Supplements: Limited Evidence

• Tribulus Terrestris: Despite widespread marketing claims, systematic reviews consistently fail to demonstrate testosterone-boosting effects in humans.

• D-Aspartic Acid: May temporarily increase testosterone in sedentary men, but effects diminish over time; no benefit shown in trained athletes.

• DHEA: Mixed evidence; may benefit older men with low DHEA-S levels but carries potential side effects and drug interactions.

• Tongkat Ali: Preliminary evidence suggests possible benefits for stress-related testosterone decline; more research needed.

When Medical Treatment Is Necessary: Testosterone Replacement Therapy

A 2024 meta-analysis published in Frontiers in Endocrinology analyzed 28 randomized controlled trials involving 3,461 patients and found that testosterone replacement therapy significantly improved International Index of Erectile Function (IIEF) scores in hypogonadal men (WMD 3.26; 95% CI 1.65-4.88; P<0.0001), regardless of administration method or treatment duration.

Additional analysis published in the Journal of Clinical Endocrinology & Metabolism confirmed that TRT in clinically hypogonadal men produces significant improvements in sexual desire/libido (SMD: 0.17), erectile function (SMD: 0.16), and sexual satisfaction (SMD: 0.16).

Who Should Consider TRT?

The Endocrine Society defines male hypogonadism as total testosterone levels below 300 ng/dL combined with at least one symptom of testosterone deficiency. Symptoms may include:

• Decreased libido and sexual interest

• Erectile dysfunction

• Reduced morning erections

• Fatigue and decreased energy

• Loss of muscle mass and strength

• Increased body fat, especially visceral

• Mood changes, irritability, or depression

• Decreased bone density

• Cognitive difficulties and "brain fog"

TRT and PDE5 Inhibitors: The Combination Approach

Research indicates that PDE5 inhibitors (medications like sildenafil and tadalafil) may be less effective in men with low testosterone because their efficacy depends on adequate nitric oxide signaling—which is regulated by testosterone. Clinical studies published in European Urology demonstrate that combining TRT with PDE5 inhibitors in hypogonadal men produces superior results compared to either treatment alone.

Critical Considerations Before Using Any Testosterone Booster

The Supplement Safety Problem

The FDA does not regulate dietary supplements with the same rigor as pharmaceutical medications. This creates several concerns:

• Inconsistent dosing: Products may contain more or less of the active ingredient than labeled

• Contamination risk: Some "natural" testosterone boosters have been found to contain undisclosed pharmaceutical compounds

• Drug interactions: Herbal supplements can interact with prescription medications in dangerous ways

• Delayed appropriate treatment: Relying on unproven supplements may delay diagnosis and treatment of underlying conditions

Why Proper Evaluation Matters

Erectile dysfunction can be an early warning sign of cardiovascular disease, diabetes, or other serious health conditions. Research published in the Journal of the American College of Cardiology found that men with ED have significantly higher rates of subclinical coronary artery atherosclerosis.

Similarly, low testosterone has multiple potential causes—including pituitary disorders, testicular dysfunction, obesity, metabolic syndrome, and certain medications. Without proper testing, the underlying cause cannot be identified or addressed.

The Arsenal Men's Health Approach: Evidence-Based, Provider-Guided Care

At Arsenal Men's Health, we believe every Utah man deserves access to the same caliber of care previously available only at elite academic medical centers. Our approach combines:

Comprehensive Evaluation

We don't guess—we test. Our evaluation process includes complete hormone panels, metabolic markers, and cardiovascular risk assessment to identify the true underlying cause of your symptoms.

Individualized Treatment Plans

No two men are identical. Treatment decisions are made by licensed medical providers based on your specific lab values, symptoms, medical history, and personal goals—not by algorithms or profit motives.

Ongoing Monitoring & Optimization

Hormone optimization isn't "one and done." We provide regular follow-up assessments to ensure your treatment remains safe and effective, making adjustments as needed based on your response.

Discreet, Convenient Telehealth

Access premium men's health care from anywhere in Utah. Our secure telehealth platform protects your privacy while providing convenient access to expert providers.

Ready to Optimize Your Health?

If you're experiencing symptoms of low testosterone or erectile dysfunction, don't waste time and money on unproven supplements. Schedule a consultation with our clinical team to get answers—and a treatment plan that actually works.

SCHEDULE YOUR FREE CONSULTATION

(385) 666-6292  |  info@arsenalmenshealth.com

Trusted by 1,200+ Utah men  •  Clinician-led care  •  100% confidential

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Medical Disclaimer: This article is for educational purposes only and does not constitute medical advice. Treatment decisions should be made in consultation with a qualified healthcare provider based on your individual circumstances. Arsenal Men's Health provides clinician-prescribed treatments under the supervision of licensed nurse practitioners.

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