What is clomiphene (Clomid)?
Clomiphene citrate, often sold as Clomid, is a prescription pill used to trigger ovulation in people who don't ovulate regularly, such as some people with PCOS. It blocks estrogen signals in the brain, so the body releases more FSH and LH to grow and release an egg. It's usually taken for five days early in the cycle.
How it works in your cycle
Clomiphene is a selective estrogen receptor modulator. It makes the hypothalamus think estrogen is low, so it sends more GnRH. The pituitary answers with more FSH to grow follicles and later an LH surge to release the egg.
| Step | Typical timing |
|---|---|
| Take clomiphene | Days 3 to 7 or 5 to 9 of the cycle |
| Ovulation | Usually about 5 to 10 days after the last pill |
| Progesterone blood test | About 7 days after expected ovulation |
Estimate your days with the Clomid ovulation calculator.
Side effects and risks
- Hot flashes, bloating, breast tenderness, headache
- Mood swings and irritability, which many people notice
- Visual changes such as blurring: stop and call your doctor
- Higher chance of twins (around 5 to 10%)
- Rarely, ovarian hyperstimulation
Why it matters
Clomiphene is a common first step in ovulation induction, but letrozole is now often preferred for PCOS because it led to more live births in trials. Treatment cycles can be emotionally draining: the hormone effects plus the two-week wait are a lot. Being kind to yourself on those days matters.
Clomiphene is prescribed and monitored by a doctor. Call them about vision changes, severe pelvic pain or swelling, rapid weight gain, or shortness of breath.
Frequently asked questions
How many cycles can you take Clomid?
Usually up to about six ovulatory cycles. If pregnancy hasn't happened by then, doctors typically move to other treatments.
Does Clomid affect mood?
Yes, mood swings, irritability and feeling teary are among the most commonly reported side effects.
Sources
- MedlinePlus: Clomiphene
- Legro RS et al. Letrozole versus clomiphene for infertility in the polycystic ovary syndrome. NEJM (2014)
This page is for information only and isn鈥檛 medical advice. If something worries you, please talk to a doctor.
Keep reading
Clomid ovulation calculator: when will I ovulate on Clomid or letrozole?Free Clomid ovulation calculator: enter cycle day 1 and your first pill day to see when you'll likely ovulate and when to start LH tests. Letrozole too.
What is letrozole?Letrozole is an aromatase inhibitor used off-label to trigger ovulation, often with PCOS. How it works, timing, side effects and how it compares with Clomid.Ovulation induction: definition and meaningOvulation induction uses medicine to help the ovaries release an egg when you don't ovulate regularly. Who it helps, the main drugs, and monitoring.
What is PCOS (polycystic ovary syndrome)?PCOS (polycystic ovary syndrome) is a common hormone condition causing irregular periods, high androgens and ovulation problems. Signs, diagnosis and care.
Infertility: definition and meaningInfertility means not getting pregnant after 12 months of regular unprotected sex, or 6 months if you're 35 or older. Causes, tests and next steps.