The Science Behind Viagra's Effectiveness
The PDE5 Mechanism
Viagra contains sildenafil citrate, which belongs to a class of medications called PDE5 inhibitors. During sexual arousal, your body naturally releases nitric oxide in the penis, which triggers the production of cyclic GMP - a chemical that relaxes smooth muscle and increases blood flow. The PDE5 enzyme normally breaks down cyclic GMP, reducing blood flow. Viagra blocks this enzyme, allowing cyclic GMP levels to remain elevated and blood flow to continue.
Blood Flow and Erection Process
When the smooth muscles in penile blood vessels relax due to increased cyclic GMP, the arteries widen and more blood flows into the penis. This increased blood flow fills the erectile chambers (corpora cavernosa), creating the firmness needed for an erection. Importantly, this process only occurs when you're sexually aroused - Viagra doesn't cause spontaneous erections.
Timing and Duration
Viagra typically begins working within 30-60 minutes after taking it on an empty stomach. Fatty meals may delay absorption and onset of action. The medication's effects can last 4-6 hours, though this doesn't mean an erection will last this entire time. Instead, it means you may find it easier to achieve erections during this window when sexually aroused.
Dosage Considerations
Viagra is available in 25mg, 50mg, and 100mg strengths. Most men start with 50mg, which can be adjusted based on effectiveness and any side effects experienced. Only one dose should be taken in any 24-hour period. Your prescriber will determine the most appropriate dose based on your medical history and current medications.
Branded vs Generic Options
Both Viagra (branded) and sildenafil (generic) contain the same active ingredient and work identically in your body. The generic version typically costs less whilst providing the same therapeutic effects. At EverydayMeds, you can choose between branded Viagra or generic sildenafil during checkout, following your online consultation with our qualified prescribers.
Important Safety Considerations
Viagra should not be taken with nitrate medications (such as GTN spray) as this combination can cause dangerous drops in blood pressure. Men with certain heart conditions, recent stroke or heart attack, or severe liver problems may not be suitable candidates. Our clinical assessment ensures the medication is safe and appropriate for your individual circumstances.












