Levonorgestrel BP: What It Is, How It Works, and What You Need to Know

When you hear levonorgestrel BP, a synthetic progestin hormone used primarily in emergency contraception and hormonal birth control. Also known as levonorgestrel, it’s one of the most common active ingredients in morning-after pills and IUDs, helping prevent pregnancy after unprotected sex or contraceptive failure. Unlike estrogen-based pills, levonorgestrel BP works without estrogen, making it safer for many people—especially those who can’t take estrogen due to blood clots, migraines, or other health concerns.

This hormone doesn’t cause an abortion. Instead, it delays or stops ovulation, thickens cervical mucus to block sperm, and sometimes changes the lining of the uterus so a fertilized egg can’t attach. It’s most effective when taken within 72 hours after unprotected sex, though some studies show it still works, just less reliably, up to 120 hours later. The BP in levonorgestrel BP stands for British Pharmacopoeia, meaning it meets strict quality and purity standards used in the UK and other countries that follow their guidelines. That’s why you’ll see it listed this way on prescriptions and packaging from reliable sources like Canadian pharmacies.

People often compare levonorgestrel BP to other options like ulipristal acetate (ella) or copper IUDs. While ella works longer and may be more effective for people over 165 pounds, levonorgestrel BP is cheaper, easier to find without a prescription in many places, and has decades of safety data. It’s also the hormone used in some daily birth control pills, like the mini-pill, where it’s taken every day without a break. If you’ve ever used a progestin-only pill, you’ve already been exposed to this compound.

Side effects are usually mild—nausea, headaches, breast tenderness, or changes in your period. Most people don’t have serious issues, but if your period is more than a week late after taking it, take a pregnancy test. It’s not 100% effective, and weight can affect how well it works. Still, it’s one of the most studied and trusted emergency options out there.

What you’ll find below are real, practical comparisons and guides that connect levonorgestrel BP to other medications people use for similar or overlapping reasons—like hormonal balance, reproductive health, and managing side effects. You’ll see how it stacks up against alternatives, what to watch for, and how to use it safely without overcomplicating things. No fluff. Just what matters.