Letrozole is a prescription-only medication in the United States, so you need a doctor’s prescription to get it. There is no legal way to purchase it over the counter. The specific type of doctor you’ll see and the steps involved depend on why you need it, whether that’s fertility treatment or breast cancer therapy.
Why Letrozole Requires a Prescription
The FDA classifies letrozole as “Rx only,” meaning a licensed healthcare provider must evaluate you before dispensing it. This isn’t just a regulatory formality. Letrozole works by blocking estrogen production, which makes it powerful but also means it can cause fetal harm during pregnancy and affects bone density and cholesterol levels over time. Your doctor needs to confirm the medication is appropriate for your situation before writing that prescription.
Getting Letrozole for Fertility
If you’re trying to conceive, letrozole is most commonly prescribed to stimulate ovulation in women with polycystic ovarian syndrome (PCOS). It’s often the first-line option, and for good reason: in women with PCOS, letrozole produces a 29% pregnancy rate compared to 15.4% with clomiphene (Clomid), and a live birth rate of 25.4% versus 10.9%. Your doctor may also prescribe it if you haven’t responded well to clomiphene.
The typical path starts with your OB-GYN or a reproductive endocrinologist (fertility specialist). Before prescribing letrozole, they’ll usually run blood work to check your hormone levels and perform an ultrasound to look at your ovaries. If you have irregular cycles, you may first be given a separate medication to induce a period so treatment can begin on the right day.
Once cleared, the standard fertility protocol involves taking one tablet daily for five days, starting on day 2 of your menstrual cycle. Your fertility team will then schedule a follow-up ultrasound to check whether a follicle has developed. The dose used for ovulation induction is typically 2.5 to 5 mg per day, and your doctor may adjust it across cycles depending on your response.
Many OB-GYNs are comfortable prescribing letrozole for fertility without referring you to a specialist, especially if your situation is straightforward. If you’ve already been diagnosed with PCOS or have documented ovulation problems, mention letrozole by name at your appointment. Doctors expect patients to come informed.
Getting Letrozole for Breast Cancer
For breast cancer, letrozole is prescribed to postmenopausal women with hormone receptor-positive tumors. It’s used in several situations: as a first treatment after surgery, as extended therapy following five years of tamoxifen, or for advanced breast cancer that has progressed after other hormonal treatments.
Your oncologist will prescribe letrozole as part of your overall cancer treatment plan. The decision is based on your tumor’s receptor status (confirmed through a biopsy), your menopausal status, and your treatment history. Because letrozole can lower bone mineral density and raise cholesterol, your oncologist will likely order baseline bone density scans and blood lipid panels before starting you on the medication, with periodic monitoring afterward.
For cancer treatment, letrozole is taken once daily on a long-term basis, often for five years or more.
Telehealth as an Option
If you don’t have easy access to a specialist, telehealth platforms now offer consultations for fertility medications in many states. Some services connect you with a reproductive endocrinologist virtually, who can order lab work at a local facility and then write a prescription if appropriate. This can speed up the process considerably compared to waiting weeks for an in-person specialist appointment. For cancer-related prescriptions, you’ll generally need an in-person oncology relationship, though follow-up visits may happen via telehealth.
Cost and Where to Fill It
Generic letrozole is widely available at nearly every pharmacy in the U.S. The listed retail price can look steep at around $544 per fill, but almost nobody pays that. With insurance, discount cards, or pharmacy coupons, the out-of-pocket cost drops dramatically, often to under $10 for a 30-day supply of the generic version. GoodRx and similar discount tools can bring the price down by over $500 off retail.
Mail-order pharmacies are another option that can lower costs further, and they’re especially convenient for long-term cancer treatment where you’re refilling monthly for years. Check whether your insurance plan offers a preferred mail-order service, as copays are sometimes lower through that route.
The brand name version, Femara, costs significantly more than generic letrozole, and there’s no clinical advantage to the brand name. If your prescription is written for Femara, ask your pharmacist about generic substitution.
What to Bring to Your Appointment
To make the process as efficient as possible, bring any relevant medical records you already have. For fertility visits, that means previous hormone test results, ultrasound reports, or documentation of irregular cycles. For oncology, bring your pathology report and any prior treatment records. If you’ve already tried clomiphene for fertility without success, mention that upfront, since it’s one of the clearest reasons a doctor will move to letrozole instead.
If cost is a concern, ask your doctor’s office about patient assistance programs. The manufacturer and several nonprofit organizations offer copay assistance or free medication programs for patients who qualify based on income.