Erectile Dysfunction

Erectile dysfunction is a type of male sexual dysfunction characterized by difficulty achieving or maintaining an erection. Erectile dysfunction can be caused by nerve or blood vessel damage, obesity, smoking, or stress.

Quick Answer

What it is

Erectile dysfunction is a type of male sexual dysfunction characterized by difficulty achieving or maintaining an erection. Erectile dysfunction can be caused by nerve or blood vessel damage, obesity, smoking, or stress.

Key findings

  • Grade B: Erections (L-Carnitine)
  • Grade B: Erectile Response (PT-141 (Bremelanotide))
  • Grade B: Erectile Function (ED Patients) (PT-141 (Bremelanotide))

Safety

No specific caution or interaction language was detected in the current summary/outcome notes.

ℹ️ Quick Facts

Quick Facts: Erectile Dysfunction

  • Supplements Studied:10
  • Research Trials:12
  • Total Participants:3,629
  • Top Supplement:Tribulus Terrestris (B)
12 trials
3,629 ppts
10 supps · 41 outcomes

Evidence-Based Protocol

Supplement stack ranked by research quality

Moderate Evidence

Primary Stack (Tier 1)

1.5-3g daily

Converted to arginine, increasing nitric oxide production and improving blood flow to erectile tissue

8 studies | 350 participants

Ginsenosides enhance nitric oxide release and relax smooth muscle in erectile tissue

12 studies | 600 participants

Supporting Stack (Tier 2)

2g daily (propionyl-L-carnitine preferred)

Improves energy metabolism in penile tissue; propionyl-L-carnitine may enhance PDE5 inhibitor response

8 studies | 400 participants
1.5-3g daily

Adaptogen that improves sexual desire and may enhance erectile function through non-hormonal mechanisms

6 studies | 250 participants
250-750mg daily

May support testosterone levels and enhance libido; traditional use for sexual dysfunction

6 studies | 300 participants
40-120mg daily

Pine bark extract that enhances endothelial nitric oxide production; often combined with L-arginine

6 studies | 250 participants
30mg daily

May improve erectile function and sexual satisfaction; especially studied in SSRI-induced dysfunction

4 studies | 150 participants

How It Works

Erectile dysfunction (ED) is the inability to achieve or maintain an erection sufficient for satisfactory sexual performance. It affects about 50% of men over 40 to some degree and becomes more common with age. ED is primarily a vascular condition—erections depend on adequate blood flow. Nitric oxide (NO) is the key molecule that relaxes blood vessels and allows blood to fill the erectile tissue. ED can also be an early warning sign of cardiovascular disease.

IMPORTANT: ED can signal underlying cardiovascular disease, diabetes, or hormonal problems. See a healthcare provider for evaluation. PDE5 inhibitors (Viagra, Cialis) remain the most effective treatment for most men.

•L-Citrulline is an amino acid that's converted to arginine in the body, which then produces nitric oxide—the molecule that relaxes blood vessels and enables erections. Citrulline is actually more effective at raising blood arginine levels than taking arginine directly. Studies show over 50% of men with mild ED report improvement.
•Panax Ginseng (Korean Red Ginseng) is the most evidence-backed herb for ED. Its active compounds (ginsenosides) enhance nitric oxide production and relax the smooth muscle in erectile tissue. Multiple meta-analyses confirm it significantly improves erectile function scores.
•L-Carnitine/Propionyl-L-Carnitine supports energy metabolism in penile tissue. Propionyl-L-carnitine specifically may enhance the response to PDE5 inhibitors (like Viagra) in men who don't respond well to medication alone. It addresses metabolic aspects of erectile function.
•Maca Root is a Peruvian plant that has been used for centuries for sexual function. Research shows it improves sexual desire and may help with mild erectile dysfunction. Interestingly, it doesn't appear to work by changing hormone levels, suggesting it acts through other mechanisms.
•Tribulus Terrestris is a traditional herb used for male sexual health. While claims about dramatically boosting testosterone are overstated, studies suggest it may modestly improve erectile function and libido in men with mild to moderate ED.
•Pycnogenol (pine bark extract) enhances nitric oxide production from the endothelium (blood vessel lining). When combined with L-arginine, studies show impressive results—up to 92% of men achieved normal erections in one trial.
•Saffron may be particularly helpful for antidepressant-induced sexual dysfunction. SSRIs commonly cause erectile problems, and saffron has shown benefit in this specific population. It may also help with libido and satisfaction.

Expected timeline: L-citrulline/Pycnogenol: days to weeks. Ginseng: 2-4 weeks. Maca/Tribulus: 4-8 weeks. Lifestyle factors (exercise, weight loss, not smoking) are also important.

Generated from peer-reviewed researchSchema v2.0

Detailed Outcomes

Grade:
Effect:
Size:
Sort:
|
B
Erections
Small Increase
2 studies
small↑Improves
?
Sexual Function
1 study
↑Improves
B
Erectile Response
In Phase 1 studies, intranasal PT-141 induced statistically significant erectile responses in healthy males and ED patients at doses >7mg, with onset in approximately 30 minutes.
moderate↑Improves
B
Erectile Function (ED Patients)
PT-141 was effective in Viagra-responsive ED patients, demonstrating a central mechanism distinct from PDE5 inhibitors.
moderate↑Improves
C
Depression Symptoms
Moderate Improvement
1 study
moderate↓Improves
?
Erections
3 studies
↑Improves
?
Sexual Function
3 studies
↑Improves
?
Penile Girth
1 study
↑Improves
C
Blood Pressure
Small Improvement
1 study
small↓Improves
?
Erections
3 studies
↑Improves
?
Testosterone
2 studies
↑Improves
?
Free Testosterone
1 study
↑Improves
?
High-density lipoprotein (HDL)
1 study
↑Improves
?
Liver Enzymes
1 study
↑Worsens
?
Low-density lipoprotein (LDL)
1 study
↓Improves
?
Luteinizing Hormone
1 study
↑Improves
?
Prostate-Specific Antigen
1 study
↑Improves
?
Serum DHEA
1 study
↑Improves
?
Sex Hormone Binding Globulin
1 study
↑Improves
?
Total cholesterol
1 study
↓Improves
?
Triglycerides
1 study
↓Improves
C
Erections
Small Increase
1 study
small↑Improves
?
Follicle-Stimulating Hormone
1 study
↑Improves
?
Luteinizing Hormone
1 study
↑Improves
?
Prolactin
1 study
↑Improves
?
Subjective Well-Being
1 study
↑Improves
?
Testosterone
1 study
↑Improves
D
Follicle-Stimulating Hormone
No effect
1 study
none
?
Libido
2 studies
↑Improves
?
Free Testosterone
1 study
↑Improves
?
Luteinizing Hormone
1 study
↑Improves
?
Prolactin
1 study
↑Improves
?
Sexual Function
1 study
↑Improves
?
Testosterone
1 study
↑Improves
D
Blood Pressure
No effect
1 study
none
?
Heart Rate
1 study
↓Improves
?
Libido
1 study
↑Improves
?
Penile Girth
1 study
↑Improves
?
Erections
2 studies
↑Improves
?
Erections
1 study
↑Improves
?
Erections
1 study
↑Improves

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