With Viagra, the peak plasma concentration is reached in around one hour, translating to an onset of action of 30 minutes or less.
To measure how well these drugs treat HSDD, doctors look at whether sexual desire has gone up and if distress about it has gone down. Volkar says flibanserin typically leads to “one more sexually significant event per month.” That may sound like a success to some and not to others. “It depends on how you define things,” she says. “Is that awesome, or is that not so great? When I'm counseling a patient, I kind of leave that to their discretion and let them decide what that means for them.” There is no “normal” amount of sex or desire.
So a change in the distress a woman feels about her sex drive is often a key sign of how well the treatment is working. If you try the medicine for 8 weeks and you haven’t felt a change, your doctor may recommend you stop taking it. The bottom line, Volkar says, is that though these treatments may not be perfect yet, having two medications available on the market is a move in the right direction. “I think it's great that we're finally doing research into medications for women and sexual desire,” she says. “I don't think it's quite the answer yet, but it’s an important first step.” While sexual dysfunction affects both men and women, men have 26 FDA-approved treatments to choose from.
A new documentary explains that it’s in part because the FDA drug approval process determines which sexual health options are available, and how restrictions or labeling decisions can limit access for certain groups. “When you look at women — premenopausal, postmenopausal, transgender individuals — the conversation of what is available to you is not dictated by you,” explains Johns Hopkins Carey Business School Law and Ethics Professor Stacey Lee in The Pink Pill: Sex, Drugs & Who Has Control. Addyi, or flibanserin, treats Hypoactive Sexual Desire Disorder, a common condition defined by lack of sexual desire in women. It has yet to achieve the same kind of widespread use or acceptance as men’s Viagra, which is used by millions of patients annually since its 1998 debut. The Pink Pill recounts the journey of Sprout Pharmaceuticals Founder and CEO Cindy Eckert, the entrepreneur whose company developed and brought Addyi to market, as she set out to expand access for sexual health treatments for women. Cialis and Viagra share mechanisms of action but differ in side effects.
According to pre-market trials, potential side effects include the following. *Based on the recommended "on-demand" dose Cialis comes in oral tablets of 2.5 mg, 5 mg, 10 mg, and 20 mg.
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Viagra Super Active | 100mg | 180 + 20 Pills | 280.97€ 267.59€ | |
| Viagra Super Active | 100mg | 20 + 4 Pills | 48.05€ 45.76€ | |
| Viagra Original | 100mg | 34 + 2 Pills | 163.67€ 155.88€ | |
| Viagra Soft Tabs | 100mg | 10 Pills | 36.93€ 35.17€ | |
| Viagra Soft Tabs | 100mg | 120 + 8 Pills | 232.21€ 221.15€ | |
| Viagra Generic | 50mg | 60 + 4 Pills | 83.93€ 79.93€ | |
| Viagra Generic | 100mg | 270 + 10 Pills | 270.47€ 257.59€ | |
| Viagra Soft Tabs | 100mg | 270 + 10 Pills | 419.95€ 399.95€ | |
| Viagra Generic | 50mg | 10 Pills | 26.87€ 25.59€ | |
| Viagra Generic | 100mg | 180 + 8 Pills | 199.37€ 189.88€ | |
| Viagra Generic | 25mg | 90 + 6 Pills | 105.03€ 100.03€ | |
| Viagra Original | 100mg | 8 Pills | 59.84€ 56.99€ | |
| Viagra Soft Tabs | 100mg | 20 Pills | 62.99€ 59.99€ | |
| Viagra Oral Jelly | 100mg | 110 + 9 Sachets | 284.63€ 271.08€ | |
| Viagra Generic | 200mg | 90 + 6 Pills | 170.79€ 162.66€ | |
| Viagra Oral Jelly | 100mg | 63 + 7 Sachets | 190.54€ 181.47€ |
For immediate ED treatment, you typically start with 10 mg and adjust based on tolerability or effectiveness.
| Study Phase | Cialis Research in Women | Viagra Research in Women | Primary Focus |
|---|---|---|---|
| Phase 1 | Limited | Limited | Safety and dosing |
| Phase 2 | Emerging | Emerging | Efficacy for sexual arousal |
| Phase 3 | Not widely conducted | Not widely conducted | Large-scale efficacy and safety studies |
Viagra is also available in oral tablets of 25 mg, 50 mg, and 100 mg.
It's typically used at 50 mg once daily, but can be increased to 100 mg if needed.
In terms of dosage, there is one big difference between Cialis and Viagra: With Cialis, you can take it "on demand" for the immediate treatment of ED or as a daily dose to achieve sustained relief of ED in a lower 2.5- or 5-mg dose.
| Side Effect | Severity | Notes |
|---|---|---|
| Headache | Mild | Common in many users |
| Flushing | Mild | Usually temporary |
| Vision Changes | Rare | Possible blue tint or blurred vision |
With Viagra, the drug is only used in anticipation of sex.
| Condition | Cialis | Viagra | Notes |
|---|---|---|---|
| Severe Heart Disease | Not recommended | Not recommended | Both should be used with caution, consult a doctor |
| Nitrates Medication | Contraindicated | Contraindicated | Severe interactions can occur |
| Eye Disorders | Caution advised | Caution advised | Particularly with pre-existing retinal issues |
Due to its short half-life, it is unsuitable for daily use.
Eckert’s path in developing Addyi for patient use was more of a struggle than it should’ve been, according to the documentary, which calls out the inequalities in availability of sexual health treatment between men and women. Lee highlights that FDA choices and approvals are not just regulatory decisions, but that they also shape who can get care and how easily. “If you’re a cisgender, white male, health care in the United States is pretty darn good, and your health care experience can be a uniquely personal one,” she said. In other words, women and minority groups often don’t have a similar, positive experience. “FDA decisions are not just scientific determinations, but structural choices that shape access, risk, and who benefits from innovation,” said Lee.
The FDA declined approval for Addyi in 2010 and 2013, with some critics referring to the treatment as “an ineffective drug for a nonexistent problem.” However, data from the University of Colorado Anschutz Department of Obstetrics and Gynecology shows that 10% of women across all age groups suffer from HSDD, which can “cause significant levels of personal distress.” To put it into perspective, HSDD is just as common as autoimmune disorders like rheumatoid arthritis, and in the U.S. alone there are nearly a million patients taking oral medication to treat their autoimmune condition. Though HSDD is not a threat to physical wellbeing, both conditions can have significant impact on a person’s life. Like most medications, Addyi doesn’t work for everyone, but its availability gives women struggling with HSDD an option that otherwise doesn’t exist. Still, early research didn’t quite satisfy the FDA.
“When the data first went up for review in 2010, the FDA did not feel that there was enough data to support Addyi’s effectiveness,” said Lee. The drug was originally tested in a clinical trial with over 2,000 premenopausal women either taking Addyi or a placebo pill. Participants taking Addyi were 10% more likely to report an increase buy female viagra in satisfying sexual events. A more recent study found that about half of women taking Addyi reported benefit to their sex life. Advocates for women’s health criticized the FDA’s early rejections and claimed gender bias, especially because Viagra was approved under an expedited priority review process, taking less than a year to achieve approval. Cialis and Viagra vary in their effectiveness when taken with food: With Cialis, you can take a dose, even a small 2.5-mg dose, with or without food.
Though the purposes of Addyi and Viagra are similar, Addyi corrects chemical imbalances of certain neurotransmitters in the brain that are responsible for sexual desire or excitement, which makes the drug approval process more complex. “Erectile dysfunction was seen as an unmet physical ailment,” said Lee. Because of that, Viagra was evaluated as treatment to address a physical need. HSDD was not considered an unmet physical ailment in the eyes of the FDA but rather an unmet psychological ailment, which “immediately triggers a higher standard of review and additional safety measures,” Lee adds. While the drugs had to be evaluated differently, supporters of Addyi claimed that stigma and overly cautious FDA warnings deterred patient use even after it was approved.
For example, doctors and pharmacists had to take a test, known as a Risk Evaluation and Mitigation Strategy assessment, to prescribe and administer Addyi. The assessment included an online slide presentation followed by a comprehension test that proved the medical professionals knew and understood the drug’s risks of potential low blood pressure and fainting when combined with alcohol. Even further, patients had to sign a paper vowing not to drink while on the medication even though Cialis--another medication used to treat erectile dysfunction in men--creates similar interactions with alcohol but comes with no more than an advisement to moderate alcohol use. At the time of approval, the FDA argued that Addyi’s interaction with alcohol hadn’t yet been adequately studied. In 2019 and after additional research was conducted, the FDA modified its original alcohol warning for Addyi and removed the test requirement for doctors and pharmacists.
In December of 2025, the FDA approved the drug for postmenopausal women, expanding access to more patients. Advocates say a drug to treat women’s sexual dysfunction is a start to addressing health inequity. Lee adds that recent bigger picture events, though, like the overturn of Roe v. Wade and rollbacks on birth control access, have changed what health care looks like for women today. The approval and acceptance viagra gel of Addyi is part of a much larger and ongoing conversation about women’s health and regulatory policy currently. The rate and degree of absorption of the drug are unaffected by food.
“The past five to 10 years really calls into question where the state of women’s health is going,” Lee said. The Pink Pill: Sex, Drugs & Who Has Control is streaming on Paramount+ in Canada and the U.S. as of March 6, 2026. Cialis lasts up to 36 hours, making it a long-acting option. Viagra works faster, with effects in 30 minutes, but lasts only about four hours.
Cialis is also approved for treating an enlarged prostate and has fewer food restrictions. Cialis and Viagra both work to treat erectile dysfunction, but they differ significantly in how long they last and when they start working. While Cialis can last up to 36 hours, Viagra offers a quicker onset within 30 minutes. Cialis (tadalafil) and Viagra (sildenafil) are both phosphodiesterase type 5 (PDE5) inhibitors used to treat erectile dysfunction (ED). They increase blood flow to the penis, which helps produce an erection suitable for sex.
A key difference between Cialis and Viagra is their duration of action, largely determined by their biological half-life. This refers to the time it takes for drug levels in the bloodstream to drop by half. Cialis has a longer half-life than Viagra, leading to a longer duration of action: Cialis: Works up to 36 hours (giving it the nickname "the weekend pill") Viagra: Works up to around four hours, with the strongest effects seen in the first two hours PDE5 inhibitors prevent the breakdown of cyclic guanosine monophosphate (cGMP), which relaxes blood vessels and increases blood flow to the penis for stronger erections. The onset of action, or how quickly Cialis and Viagra work, depends on their peak plasma concentration—the point when the drug reaches its highest level in the blood after liver metabolism. With Cialis, the peak plasma concentration is reached in around two hours, translating to an onset of action of roughly one hour. With Viagra, taking a dose with food, especially high-fat foods, reduces its absorption and can make it less effective.