Erectile dysfunction is defined as the persistent inability to achieve or maintain a penile erection sufficient for satisfactory sexual performance. The Massachusetts Male Aging Study surveyed 1,709 men aged 40–70 years between 1987 and 1989, revealing a total prevalence of erectile dysfunction of 52 per cent. In 1995, it was estimated that over 152 million men worldwide experienced erectile dysfunction, and projections suggest that by 2025, this number will rise to approximately 322 million. 

Historically, erectile dysfunction was often attributed to psychological issues. However, it is now understood that, for most men, erectile dysfunction is primarily caused by physical problems, often related to the blood supply to the penis. This shift in understanding has led to significant advances in both the diagnosis and treatment of erectile dysfunction.

Erectile dysfunction is widespread among older men and can be caused by various organic factors, including abnormalities in the penile arteries or veins. Arterial problems are often due to arteriosclerosis or hardening of the arteries, which can be exacerbated by controllable risk factors like being overweight, lack of exercise, high cholesterol, high blood pressure, and smoking. These risk factors can cause erectile failure even before affecting the heart. Atrophy (a decrease in muscle mass when protein degradation exceeds protein synthesis) and fibrosis of the smooth muscle tissue in the penis can also contribute to erectile dysfunction. This can lead to issues with maintaining a firm erection, which is often an early symptom of erectile dysfunction. Although this condition is called venous leak, the problem lies with the malfunctioning smooth muscle around the veins. This results in the difficulty of maintaining an erection and is now believed to be an early manifestation of atherosclerosis and vascular disease.

While prescription medications like sildenafil (Viagra), vardenafil (Levitra), tadalafil (Cialis), and avanafil (Stendra) are well-known treatments, some people turn to natural remedies and supplements. These alternatives, often used in Chinese, African, and other traditional practices, haven’t undergone the same rigorous testing as prescription drugs. This lack of research means that their effectiveness and safety must be well-established and can cause side effects or interact with other medications. 

The potency of active ingredients in supplements can vary widely from product to product, making them unreliable. It is crucial to approach such remedies cautiously and consult a healthcare professional to ensure safety and efficacy. Here are some of the most common dietary supplements for erectile dysfunction.

Vitamin D

Vitamin D, or calciferol, is a fat-soluble vitamin vital for numerous bodily functions. It can be obtained through certain foods, dietary supplements, and sunlight exposure. When ultraviolet rays from the sun hit the skin, they trigger vitamin D synthesis, which then undergoes two hydroxylations in the body—first in the liver to become 25-hydroxyvitamin D (calcidiol), and then in the kidneys to form the active 1,25-dihydroxyvitamin D (calcitriol). Vitamin D plays a crucial role in promoting calcium absorption in the gut, maintaining serum calcium and phosphate levels, and supporting bone health. It prevents conditions like rickets in children and osteomalacia in adults, and it works alongside calcium to protect older adults from osteoporosis. Additionally, vitamin D reduces inflammation and modulates cell growth, neuromuscular and immune function, and glucose metabolism.

Recent studies have explored the role of vitamin D in sexual function, particularly its impact on erectile dysfunction. A significant association has been found between low vitamin D levels and the severity of erectile dysfunction. For instance, a 2020 analysis suggested that men with lower vitamin D levels experienced more severe symptoms of erectile dysfunction compared to those with adequate levels. Similarly, a 2016 study of men with type 2 diabetes indicated higher rates and more severe symptoms of erectile dysfunction in those with vitamin D deficiency. Vitamin D is believed to support erectile function by enhancing blood flow to the penis and aiding in the production of sex hormones like testosterone.

L-arginine

L-arginine is a semi-essential amino acid that our bodies can produce. We also obtain it from various foods like meats and nuts. It’s a critical substrate for the enzyme nitric oxide synthase (NOS). It produces nitric oxide—a molecule vital for numerous physiological functions. In the vascular endothelium, nitric oxide is responsible for smooth muscle cell relaxation, which helps lower blood pressure and improve endothelial function. Enhanced endothelial function is crucial for preventing cardiovascular diseases.

Furthermore, l-arginine plays a significant role in the immune system. The enzyme inducible NOS uses it to produce nitric oxide for cell signalling or oxidative bactericidal actions. This can help reduce infection rates, particularly when the immune function is compromised, such as during surgery or critical illnesses. By supporting nitric oxide production, l-arginine can improve blood flow and cardiovascular health, making it a valuable nutrient for maintaining overall health. Additionally, its immune-boosting properties make it beneficial for reducing infection rates in vulnerable individuals. Overall, incorporating l-arginine-rich foods into your diet or considering supplements can positively impact your cardiovascular and immune health.

The production of nitric oxide is essential for erectile function. Nitric oxide helps relax blood vessels, allowing oxygen-rich blood to flow more freely through the arteries. This healthy blood flow to the penile arteries is crucial for achieving and maintaining normal erections. Foods rich in L-arginine, such as meats and nuts or L-arginine supplements, can potentially enhance erectile function by supporting nitric oxide production, promoting better circulation, and ensuring the necessary blood supply to the penis. This can help alleviate issues related to erectile dysfunction and improve overall sexual health. L-arginine has shown promise as an effective treatment for erectile dysfunction. In a 2019 analysis, supplementation with 1,500 to 5,000 milligrams of L-arginine resulted in significant improvements in International Index of Erectile Function (IIEF) scores, suggesting it may benefit mild to moderate erectile dysfunction. 

A 2020 study also demonstrated similar improvements when L-arginine was used alone or in combination with tadalafil, a prescription medication for erectile dysfunction. This indicates that L-arginine can enhance erectile function by supporting nitric oxide production and improving blood flow to the penile arteries.

Tribulus Terrestris

Tribulus terrestris is a hardy annual plant from the caltrop family (Zygophyllaceae) that thrives in dry climates where few other plants can survive. Native to warm temperate and tropical regions of southern Eurasia and Africa, it has also spread to North America and Australia. Known for its aggressive and invasive nature. 

Tribulus Terrestris produces small woody fruit with long, sharp spines capable of penetrating surfaces like bare feet, thin shoes, bicycle tyres, and even the mouths and skin of grazing animals. Despite its reputation as a noxious weed, it is widely used in traditional medicine for its potential health benefits.

Tribulus Terrestris (TT) has been recognised for its potential to enhance male sexual desire and mating behaviour. Research on primates has shown that intravenous administration of TT extracts increased plasma testosterone, dihydrotestosterone, and dehydroepiandrosterone sulphate. In rabbits and rats, oral administration of TT extract boosted dihydrotestosterone levels. A clinical trial involving daily oral intake of TT (450 mg) for 30 days in patients with erectile dysfunction resulted in significantly higher serum testosterone concentrations and improved erectile function. The study concluded that TT may be a safe and effective treatment for enhancing sexual desire and erectile function. 

Further clinical trials with larger sample sizes must confirm its safety and efficacy before it can be widely recommended for patients. While Tribulus terrestris may increase testosterone levels, it has also shown the potential to boost libido. Studies indicate that men with reduced sex drives who consumed 750–1,500 mg daily for two months experienced a 79% increase in sexual desire.

Similarly, 67% of women with very low libidos saw increased sexual desire after taking 500–1,500 mg for 90 days. Other research has reported enhanced sexual desire, arousal, and satisfaction in women with low libido. Results for men with erectile dysfunction are mixed, with some showing no effect at 800 mg per day. In comparison, others report significant improvements at 1,500 mg daily. More research is needed to understand the extent of these effects fully.

Berberine

Berberine, an isoquinoline alkaloid found in plants like Berberis vulgaris, Coptis rhizome, Berberis aristata, and Phellodendron amurense, has been traditionally used to treat a variety of conditions such as diabetes, obesity, hyperlipidemia, cardiovascular diseases, and cancer. Recent studies suggest it might also be beneficial for addressing erectile dysfunction in men. Recent research demonstrated that berberine could enhance penile erections in New Zealand White male rabbits. When administered via intracavernous injection at doses of 1, 2, 3, and 5 mg/kg, berberine increased intracavernous pressure and facilitated relaxation of the corpus cavernosum in the penis. This relaxation is linked to berberine’s effects on endothelial cells and nitric oxide (NO) production.

Additionally, berberine may work through potassium (K+) channel blockade, as evidenced by its interaction with charybdotoxin and 4-AP. The findings suggest that berberine could potentially serve as a natural agent for intravenous therapy in treating erectile dysfunction. In a separate study, researchers explored berberine’s antioxidant effects on corpus cavernosum smooth muscle cells exposed to oxidative stress from hydrogen peroxide. Berberine treatment (10−1000 μmol/L) mitigated oxidative damage, improving cell viability, NO production, and superoxide dismutase enzyme activity. This suggests berberine’s potential as an antioxidant to combat ED. 

Despite these promising results, clinical studies do not assess berberine’s safety and efficacy in humans. Future clinical trials are necessary to evaluate its potential as a reliable and safe treatment for erectile dysfunction.