Reviewed by a GPhC-registered Pharmacist at Newdays Pharmacy | Published: 2026 | Book an appointment
| Quick Answer: Both ellaOne (ulipristal acetate) and Levonelle (levonorgestrel) are emergency contraceptive pills available without prescription from pharmacies in the UK. ellaOne is effective for up to 120 hours (five days) after unprotected sex and is generally considered more effective than Levonelle, particularly in the later part of the 72-hour window and for women with a higher BMI. The copper IUD is the most effective emergency contraceptive available if inserted within five days. |
Emergency contraception is one of the most time sensitive clinical decisions in pharmacy practice, and the choice between available options is not simply a matter of which one the pharmacy has in stock. At Newdays Pharmacy in Berkshire, our pharmacists provide evidence-based consultations to help patients choose the most appropriate option based on the timing of unprotected sex, BMI, and other clinical factors.
How Levonelle Works and When to Use It
Levonelle contains levonorgestrel 1.5 mg, a synthetic progestogen. It works primarily by delaying or inhibiting ovulation. It does not prevent implantation and is not effective if ovulation has already occurred. Levonelle is licensed for use within 72 hours (three days) of unprotected sex. Efficacy is strongly time dependent as studies have estimated;
- Within 24 hours: approximately 95 percent effective at preventing pregnancy
- 24 to 48 hours: approximately 85 percent effective
- 48 to 72 hours: approximately 58 percent effective
Levonelle is available without prescription from UK pharmacies. It may be less effective in women with a BMI above 26 and significantly less effective at a BMI above 35, because levonorgestrel is distributed through body tissues and higher body weight may reduce peak plasma concentrations.
How ellaOne Works and When It Is Preferred
ellaOne contains ulipristal acetate 30 mg, a selective progesterone receptor modulator. It works by delaying or inhibiting ovulation and has an effect on endometrial receptivity. ellaOne is effective for up to 120 hours (five days) after unprotected sex, providing a longer treatment window than Levonelle.
Clinical studies have shown that ellaOne is at least as effective as Levonelle when taken within 72 hours, and significantly more effective than Levonelle between 72 and 120 hours. ellaOne also appears to maintain more consistent efficacy throughout its five day window. Body weight appears to have less impact on ellaOne’s efficacy than on Levonelle.
| ellaOne (ulipristal acetate)Window: up to 120 hours (5 days)More effective 72–120 hoursLess affected by higher BMIAvailable without prescriptionDo not take hormonal contraception for 5 days after | Levonelle (levonorgestrel)Window: up to 72 hours (3 days)Efficacy declines sharply over timeLess effective at BMI above 26Available without prescriptionCan restart hormonal contraception same day |
Important Interaction: ellaOne and Hormonal Contraception
An important clinical point: ulipristal acetate (ellaOne) and progestogen-containing contraceptives are mutually antagonistic. After taking ellaOne, hormonal contraception (pill, patch, ring, implant, injection) should not be resumed for at least five days. The progestogen in these methods reduces ellaOne’s effectiveness if taken too soon. During the five day period after taking ellaOne, barrier contraception must be used.
The Copper IUD: The Most Effective Option
Neither oral emergency contraceptive pill matches the effectiveness of the copper intrauterine device (IUD) as emergency contraception. Inserted within five days of unprotected sex (or within five days of expected ovulation in certain circumstances), the copper IUD has a failure rate of less than 0.1 percent and provides ongoing contraception for five to ten years. It is particularly recommended for women with a BMI above 35, where oral EHC effectiveness is substantially reduced. Copper IUD insertion requires a clinical appointment, typically at a GP, sexual health clinic, or family planning service.
| Book Now: Book a Travel Health Consultation or Weight Management Appointment: We serve patients from Windsor, Eton, Twyford, Reading, and across Berkshire and Buckinghamshire. |
Frequently Asked Questions
If it has been between 72 and 120 hours since unprotected sex, ellaOne (ulipristal acetate) is the only emergency contraceptive pill licensed for use. Levonelle is licensed for use only within 72 hours. Visit Newdays Pharmacy for a confidential consultation, where our pharmacist can recommend the most appropriate option for you.
ellaOne can interact with hormonal contraception, including the combined and progesterone-only pill, reducing its effectiveness. After taking ellaOne, you should wait five days before restarting hormonal contraception and use condoms or another barrier method during this time. Your pharmacist will explain the correct guidance during your consultation.
ellaOne is available from Newdays Pharmacy following a confidential pharmacist consultation. The current price will be confirmed during your appointment. In some areas, emergency contraception may also be available free of charge through NHS sexual health services or local commissioned schemes.
| Clinical Disclaimer: This article is intended for general information only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any treatment or medication. Information is accurate as of the date of publication and reviewed by a GPhC-registered pharmacist. Newdays Pharmacy is registered with the General Pharmaceutical Council (GPhC). Branch registration numbers: Eton/Windsor 1029048 | Twyford 1028983 | Coley Park Reading 1029008. |