Dr. Deepali is a qualified dental surgeon with a Bachelor of Dental Surgery (BDS) degree from the esteemed MR Ambedkar Dental College, Bangalore. With a strong foundation in clinical healthcare and a deep-rooted passion for storytelling, she has transitioned into the world of medical writing—where science meets empathy. Drawing from years of hands-on experience in patient care, Dr. Deepali specializes in simplifying complex health information into clear, relatable, and trustworthy content. Her journey as a writer began long before her medical career—with published articles, play scripts, and creative pieces written during her school and college years. Today, she combines that creative flair with her medical background to write well-researched articles on sexual wellness, general health, mental well-being, and more. Her core belief is that health content should empower—not overwhelm. She is especially passionate about patient education and uses her writing to bridge the gap between medical jargon and everyday understanding. Every article she creates is grounded in scientific evidence, empathy, and accessibility.
Our experts continually monitor the health and wellness space, and we update our articles when new information became available.
Updated on 8th August 2025
Sildenafil (commonly known as Viagra) is a highly effective, FDA-approved medication that has revolutionized erectile dysfunction treatment by targeting the root cause- poor blood flow to the penis. The medication is typically taken 30-60 minutes before intimacy, with flexible dosing from 20-100mg depending on individual needs, effectiveness lasting 4-6 hours, and common mild side effects like headaches and flushing that often improve with continued use. While generally safe for most men, sildenafil requires careful medical evaluation due to serious contraindications with nitrate medications and certain heart conditions.
If you’re searching for what is sildenafil used for, here’s the quick answer: it’s most commonly prescribed to treat erectile dysfunction (ED) by increasing blood flow to the penis during sexual arousal, helping men achieve and maintain a firm erection.
It’s also used in certain cases to manage pulmonary arterial hypertension, a heart-related condition affecting blood vessels in the lungs.
Sildenafil has been extensively studied, FDA-approved, and trusted by millions worldwide. In this article, we’ll break down how it works, the right way to take it, potential side effects, safety considerations, and tips for getting the best results. By the end, you’ll know exactly when and how sildenafil might be the right solution for you.
Sildenafil, commonly known by the brand name Viagra, is one of the most widely prescribed treatments for erectile dysfunction (ED).
Sildenafil is available as liquid sildenafil, tablets, and oral suspension. It belongs to a group of medicines called phosphodiesterase type 5 inhibitors (PDE5 inhibitors). It works by increasing blood flow to the penis during sexual stimulation.
Here’s an interesting bit of medical history: sildenafil was originally developed to treat pulmonary arterial hypertension (PAH), a heart condition affecting blood vessels in the lungs.[1]
But during clinical trials[2], researchers noticed an unexpected effect: improved erections. This discovery led to its approval for erectile dysfunction treatment, making it the first oral medication of its kind.
Today, generic sildenafil offers the same active ingredient as brand-name Viagra at a more affordable price, with most insurance plans providing coverage.
Sildenafil works by improving blood flow to your penis, but only when you’re sexually aroused. Here’s what happens step by step:
When sexually stimulated, the body releases a natural chemical called nitric oxide in the penis. This nitric oxide tells your blood vessels to relax and open up by activating another chemical called cGMP(guanylate cyclase). That helps more blood flow into the penis, which is what gives you an erection.
But there’s a catch: the body also produces an enzyme called PDE5, which breaks down cGMP, and that can make it harder to maintain an erection. That’s where sildenafil steps in.
Sildenafil blocks PDE5, which means cGMP stays around longer. This keeps the blood vessels relaxed and the blood flowing smoothly, allowing for a firmer and longer-lasting erection.
Studies[3] show sildenafil works well for ED. About 57% of sexual attempts were successful with sildenafil, compared to 21% without it. During ED treatment, 83% of men had at least one successful attempt, and 78% said their erections improved.
According to Allo Health’s internal data from over 2.5 lakh clinic patients, nearly 1 in 2 men face erectile dysfunction at some point. Among the 75,087 ED patients we’ve treated at Allo Health, sildenafil remains a top choice, with over 70% reporting better erections and 80% feeling more sexually confident within months.
ED is a lot more common than you think, and talking about it is the first step to fixing it. Medications like sildenafil are safe, effective, and nothing to be ashamed of.
To get the best results, sildenafil should be taken about 1 hour before sexual activity. But it can be taken anywhere from 30 minutes to 4 hours before sex, depending on how your body responds.
The usual starting dose is 50 mg, taken once a day. But your doctor may adjust this to 25 mg or 100 mg, depending on how effective it is for you and how well you tolerate it.
Once you take it, the effects(sildenafil working time) typically last for about 4 hours, but for some people, it may continue working for up to 12 hours.
Keep in mind, sildenafil won’t give you an erection on its own. It only works when you’re sexually aroused, so intimacy and stimulation during sexual activity are still needed.
While 20mg isn’t a standard starting dose, it can be perfect for certain situations:
Your healthcare provider can help determine if this customized dose is right for you.
Allo asks
These are rare adverse effects, but require urgent medical attention:
Sildenafil works best for men whose ED is related to:
Avoid or use only under strict supervision if you have:
Sildenafil should not be taken with:
Sildenafil is a well-tested, trusted treatment for erectile dysfunction, with strong clinical evidence and millions of success stories. But the best way to know if it’s right for you is to talk to a doctor.
Your doctor can confirm if sildenafil is safe for you, help find the right dose and timing, and address any underlying causes.
If ED is affecting your life, don’t wait. Effective help is available, and it starts with an open, honest discussion about your health.
"The following blog article provides general information and insights on various topics. However, it is important to note that the information presented is not intended as professional advice in any specific field or area. The content of this blog is for general educational and informational purposes only.
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The content should not be interpreted as endorsement, recommendation, or guarantee of any product, service, or information mentioned. Readers are solely responsible for the decisions and actions they take based on the information provided in this blog. It is essential to exercise individual judgment, critical thinking, and personal responsibility when applying or implementing any information or suggestions discussed in the blog."
