Addyi Side Effects: What the Label and Trials Show
The short answer
The most common Addyi side effects are dizziness, sleepiness, nausea and tiredness. In the label's trials of premenopausal women, about 11% on Addyi reported dizziness and 11% sleepiness, compared with 2% to 3% on placebo, and most side effects began in the first two weeks. Its boxed warning is about severe low blood pressure and fainting with alcohol taken too close to the dose, certain other medicines, or liver problems.
What is Addyi?
Addyi (flibanserin) is a pill taken once a day at bedtime for low sexual desire. It acts on brain chemicals involved in desire rather than on blood flow. According to its prescribing information, revised in December 2025, it is FDA-approved for women under 65 with acquired, generalized hypoactive sexual desire disorder (HSDD) that is not caused by another condition, relationship problems or a medicine.
All of the numbers below come from that label, which pools six placebo-controlled trials: about 1,500 premenopausal women and 800 postmenopausal women under 65 took Addyi 100 mg at bedtime.
How common are Addyi side effects?
By the numbers
Most common Addyi side effects, premenopausal trials (Addyi vs placebo)
The full list of side effects reported by at least 2% of women, and more often than with placebo, is below. The postmenopausal column comes from two trials in women under 65.
| Side effect | Premenopausal: Addyi | Premenopausal: placebo | Postmenopausal: Addyi | Postmenopausal: placebo |
|---|---|---|---|---|
| Dizziness | 11.4% | 2.2% | 7.9% | 3.3% |
| Sleepiness | 11.2% | 2.9% | 7.7% | 1.8% |
| Nausea | 10.4% | 3.9% | 6.6% | 3.9% |
| Fatigue | 9.2% | 5.5% | 3.0% | 3.9% |
| Insomnia | 4.9% | 2.8% | 5.7% | 3.4% |
| Dry mouth | 2.4% | 1.0% | 2.4% | 1.3% |
| Anxiety | 1.8% | 1.0% | 2.6% | 1.6% |
| Constipation | 1.6% | 0.4% | 2.5% | 1.8% |
The label notes that most of these began within the first 14 days of treatment. Overall, 13% of premenopausal women and 9% of postmenopausal women stopped Addyi because of a side effect, compared with 6% and 5% on placebo. Dizziness, nausea, insomnia, sleepiness and anxiety were the most common reasons.
Why is Addyi taken at bedtime?
The label says Addyi is dosed at bedtime because taking it during waking hours increases the risk of low blood pressure, fainting, accidental injury and sleepiness. Many people find the sleepiness and dizziness easier to live with when they happen during sleep. The label also warns not to drive or do anything that needs full alertness until at least six hours after a dose and until you know how it affects you.
The boxed warning: alcohol, other medicines and the liver
Addyi carries a boxed warning, the FDA’s most prominent kind, about severe low blood pressure (hypotension) and fainting (syncope) in three situations:
- Alcohol close to the dose. Wait at least two hours after one or two standard drinks before taking Addyi at bedtime. After three or more drinks that evening, skip the dose.
- Certain other medicines. Addyi is contraindicated with moderate or strong CYP3A4 inhibitors, which include some antifungals, antibiotics, HIV medicines and others. The label lists grapefruit juice as a moderate inhibitor too. Your prescriber and pharmacist need your complete medication list.
- Liver problems. Addyi is contraindicated in people with hepatic impairment, because the drug builds up in the blood.
If you drink most evenings, discuss whether Addyi fits your routine before you start.
Does Addyi work well enough to justify the side effects?
The benefit in trials was modest on average. A 2016 meta-analysis found about half an extra satisfying sexual event per month compared with placebo, graded the overall quality of the evidence as very low, and found clearly higher risks of dizziness, sleepiness, nausea and fatigue. Some women benefit more than average and some not at all. The label says to stop after 8 weeks if there is no improvement, which limits how long anyone takes it without benefit.
How Addyi compares with other options
| Option | How it’s used | Most common side effects | FDA status |
|---|---|---|---|
| Addyi (flibanserin) | Pill every night | Dizziness, sleepiness, nausea | FDA-approved for HSDD in women under 65 |
| Vyleesi (bremelanotide) | Injection as needed before sex | Nausea, flushing, headache | FDA-approved for HSDD in premenopausal women |
| Compounded options such as Blys | As prescribed, for example before intimacy | Depend on the ingredients | Compounded, not FDA-approved |
See Vyleesi side effects and PT-141 vs Addyi for the injectable option, and what Addyi costs if price is part of the decision.
Blys is a compounded, rapid-dissolve tablet that combines PT-141, oxytocin and tadalafil and is taken 30 to 60 minutes before intimacy instead of every night. It is compounded and not FDA-approved, and because it contains tadalafil it must never be used with nitrate medicines. A licensed clinician reviews your health history and medicines and decides whether it is appropriate.
When to call a clinician
Common questions
What are the most common side effects of Addyi?
Dizziness, sleepiness, nausea and fatigue were the most common in clinical trials, followed by insomnia and dry mouth. Most began within the first 14 days of treatment. The label says it is taken at bedtime because taking it while awake raises the risk of low blood pressure, fainting and sleepiness.
Can you drink alcohol on Addyi?
The current label says to wait at least two hours after one or two standard drinks before taking Addyi at bedtime, and to skip that night's dose after three or more drinks. Drinking close to the dose raises the risk of severe low blood pressure and fainting.
Does Addyi cause weight gain?
Weight gain is not among the common side effects listed on the Addyi label. If you notice a change in weight or appetite, mention it to your prescriber.
How long do Addyi side effects last?
In trials, most side effects began in the first two weeks. The label does not say how long each lasts. If a side effect is bothersome or doesn't settle, talk to your prescriber rather than stopping or changing the dose on your own.
Sources
Amie prescribes in all 50 states. Find low libido treatment in your state.