Tadalafil, sold under the brand name Cialis, belongs to the class, selective phosphodiesterase type 5 inhibitors (PDE5). It is an FDA-approved drug primarily used for the treatment of erectile dysfunction and benign prostatic hyperplasia. It has been shown to increase blood flow to the penis, thus stimulating erection. Furthermore, research shows that it exerts a positive effect on pulmonary arterial hypertension and the cardiovascular system. At Pinnacle Peptides, tadalafil for sale is exclusively available for research and experimentation.

From Pubchem

IUPAC Name: (2R,8R)-2-(1,3-benzodioxol-5-yl)-6-methyl-3,6,17-triazatetracyclo[8.7.0.03,8.011,16]heptadeca-1(10),11,13,15-tetraene-4,7-dione
Synonyms: Cialis, Tadanafil
Molecular Formula: C22H19N3O4
Molecular Weight: 389.4 g/mol
CAS number: 171596-29-5
PubChem CID: 110635

Tadalafil was first developed by the collaboration of two companies named ICOS and GlaxoSmithKline in 1991. In 1996, Glaxo discontinued the partnership as drug development was not the company’s core objective. Later, ICOS formed a joint venture named Lilly ICOS with another company Elly Lilly in 1998 to further develop tadalafil. Consequently, the drug was approved by the FDA following the successful completion of clinical trials in 2003. Later, the FDA expanded tadalafil’s approval to treat signs and symptoms of benign prostatic hyperplasia.

Tadalafil has more selectivity to the phosphodiesterase type 5 enzyme as compared to sildenafil. PDE5 is an enzyme present in the smooth muscles of different tissues, including the lungs, prostate, kidney, bladder, cerebellum and urethra.

Normally, sexual stimulation leads to the release of cyclic guanosine monophosphate (cGMP). cGMP acts as a secondary messenger and activates the processes that ultimately lead to the relaxation of smooth muscles in the penile arteries. This, in turn, increases the blood flow to the penis and causes erection.

PDE5 is responsible for catalyzing the breakdown of cGMP. By blocking the action of PDE5, tadalafil prevents the degradation of cGMP and increases its concentration. Enhanced accumulation of cGMP in the penis leads to vasodilatory effects and sustained erection.

1. Benign Prostatic Hyperplasia

Benign Prostatic hyperplasia (BPH) is characterized by the enlargement of the prostate gland. It is benign (non-cancerous) in nature. It is caused by the excessive proliferation of smooth and epithelial cells in the prostate transition zone. BPH results in obstruction of urinary flow and causes lower urinary tract symptoms, such as dribbling and incomplete urination. Research shows that tadalafil can alleviate discomfort associated with BPH [1,2].

Experts think that the mechanism behind this effect is related to Cialis' ability to boost NO/cGMP activity. This, in turn, decreases the tension in smooth muscle cells and reduces the growth in prostate tissues. Further, it has been shown to stimulate afferent nerves, resulting in enhanced perfusion of blood and decreased inflammation markers [3].

2. Cardioprotective Effect

Research suggests that tadalafil might have the potential to exhibit cardioprotective effects. Tadalafil improves blood flow in coronary arteries through NO/cGMP pathway. Plus, it has also been shown to suppress inflammation, the reason behind various cardiovascular disorders.

One study was conducted to look at the effects of Cialis on a mouse model of diabetes subjected to injury induced by ischemia-reperfusion. Participants were treated with either 1 mg/kg drug or placebo daily for 28 days. The researchers concluded that the treatment lowered the fasting blood glucose and triglyceride levels. It also found that Cialis reduced the infarct size and suppressed the inflammatory cytokines [4].

3. Peripheral Neuropathy

Peripheral Neuropathy is a complication of chronic diabetes. Studies in animal and human models have shown that treatment with PDE5 inhibitors can reduce the symptoms of peripheral neuropathy. Research conducted on animal models found that Cialis improved the conduction velocities in the sciatic nerve. It also found that the drug enhanced the blood flow in the sciatic nerve tissue region and reversed the diabetes-induced reduction in the thickness of myelin and axon diameter [5].

4. Erectile dysfunction

FDA has already approved tadalafil for the treatment of erectile dysfunction. In a double-blind, placebo-controlled trial, ED patients were randomly assigned to two four-week treatment intervals during which they were instructed to engage in sexual intercourse 24 and 36 hours after placebo or drug administration. The findings indicated that tadalafil significantly increased attempts at intercourse, with higher rates observed at both 36 hours (59.2%) and 24 hours (52.9%) after taking tadalafil as compared to the placebo [6].

Furthermore, research suggests that daily use of tadalafil is more effective in enhancing erectile function than on-demand tadalafil [7]. In a long-term efficacy study, tadalafil at doses of 5mg, 10mg, and 20 mg administered daily for up to 18-24 months was generally well tolerated [8]. Furthermore, comparative studies have indicated a potential preference for tadalafil over sildenafil due to its prolonged duration of action [9].

5. Neuroprotection

In addition to regulating cGMP levels, PDE-5 inhibitors have been shown to increase cAMP (cyclic adenosine monophosphate) levels. Both cGMP and cAMP play crucial roles in mediating various brain functions under different physiological and pathological conditions. A study revealed that tadalafil enhances functional recovery in a rat model of embolic stroke. Experts suggested that this improvement might be related to the increased levels of cGMP and enhanced angiogenesis [10].

Tadalafil has been shown to mitigate the effects of spinal cord injury by elevating nitric oxide (NO) and superoxide dismutase (SOD). NO acts as a retrograde transmitter, leading to heightened cGMP production, while SOD neutralizes superoxide radicals, reducing oxidative stress in the body. Through increased NO and SOD production, tadalafil may promote a positive response to injury and alleviate the oxidative stress associated with spinal cord injuries [11].

Tadalafil is a phosphodiesterase type 5 inhibitor. It prevents the degradation of cGMP and improves blood flow to the penis. Furthermore, research shows that it can reduce infarct size following ischemia, improve injury healing and alleviate symptoms of peripheral neuropathy. It is approved by the FDA for the treatment of erectile dysfunction and benign prostatic hyperplasia. At Pinnacle Peptides, we offer tadalafil purchase exclusively for research and educational institutions. Only buy tadalafil if you are a licensed researcher.

1. McVary, K.T., et al., Tadalafil Relieves Lower Urinary Tract Symptoms Secondary to Benign Prostatic Hyperplasia. Journal of Urology, 2007. 177(4): p. 1401-1407.
2. Casabé, A., et al., Efficacy and Safety of the Coadministration of Tadalafil Once Daily with Finasteride for 6 Months in Men with Lower Urinary Tract Symptoms and Prostatic Enlargement Secondary to Benign Prostatic Hyperplasia. Journal of Urology, 2014. 191(3): p. 727-733.
3. Hatzimouratidis, K., A review of the use of tadalafil in the treatment of benign prostatic hyperplasia in men with and without erectile dysfunction. Ther Adv Urol, 2014. 6(4): p. 135-47.
4. Varma, A., et al., Anti-inflammatory and cardioprotective effects of tadalafil in diabetic mice. PLoS One, 2012. 7(9): p. e45243.
5. Wang, L., et al., Tadalafil Promotes the Recovery of Peripheral Neuropathy in Type II Diabetic Mice. PLoS One, 2016. 11(7): p. e0159665.
6. Porst, H., et al., Efficacy of tadalafil for the treatment of erectile dysfunction at 24 and 36 hours after dosing: a randomized controlled trial. Urology, 2003. 62(1): p. 121-5; discussion 125-6.
7. McMahon, C., Comparison of Efficacy, Safety, and Tolerability of On‐Demand Tadalafil and Daily Dosed Tadalafil for the Treatment of Erectile Dysfunction. The Journal of Sexual Medicine, 2005. 2(3): p. 415-427.
8. Montorsi, F., et al., Long-Term Safety and Tolerability of Tadalafil in the Treatment of Erectile Dysfunction. European Urology, 2004. 45(3): p. 339-345.
9. Doggrell, S.A., Comparison of clinical trials with sildenafil, vardenafil and tadalafil in erectile dysfunction. Expert Opinion on Pharmacotherapy, 2005. 6(1): p. 75-84.
10. Zhang, L., et al., Tadalafil, a long-acting type 5 phosphodiesterase isoenzyme inhibitor, improves neurological functional recovery in a rat model of embolic stroke. Brain Research, 2006. 1118(1): p. 192-198.
11. Serarslan, Y., et al., Protective effects of tadalafil on experimental spinal cord injury in rats. Journal of Clinical Neuroscience, 2010. 17(3): p. 349-352.