FDA Approves Gwyn Lo, a New Low-Dose Contraceptive Patch

FDA Approves Gwyn Lo, a New Low-Dose Contraceptive Patch

The FDA has approved Gwyn Lo, a once-weekly, low-dose estrogen combined hormonal contraceptive patch, Viatris announced on July 29, 2026.¹ The once-weekly transdermal patch combines norelgestromin (220 mcg/day) and ethinyl estradiol (20 mcg/day) and is applied once weekly for 3 consecutive weeks, followed by 1 patch-free week. The approval adds a new low-estrogen option to a contraceptive patch market. Existing hormonal contraceptive options include pills, rings, and other transdermal patches as women’s contraceptive needs and preference vary.

LUMINOUS Study Shows Efficacy and Safety

The patch was approved for women of childbearing potential; clinical trial participants were women aged 18 to 35 years with a body mass index (BMI) under 30 kg/m². Gwyn Lo is contraindicated in women with a BMI of 30 kg/m² or higher and in women over 35 who smoke, due to an increased risk of serious cardiovascular events; the FDA label also notes that venous thromboembolism risk may be greater in women with a BMI above 30 kg/m² compared with those with a lower BMI.

"Gwyn Lo will provide a discreet option for women seeking a reversible, noninvasive, once-weekly contraception patch with a low dose of estrogen," Philippe Martin, Viatris' chief research and development officer, said in a statement.

The FDA approval was supported by the phase 3 LUMINOUS study, which demonstrated contraceptive efficacy, safety, and robust patch adhesion. The primary efficacy end point, the Pearl Index, was 4.14 pregnancies per 100 woman-years (95% CI, 2.77-5.95). The study also showed strong adhesion under real-world conditions: only 1.3% of 39,790 patches fully detached over the year-long trial. The most common adverse reactions (≥ 2%) were application site irritation (4.8%), application site erythema (3.7%), application site pruritus (3.7%), intercycle bleeding (3.9%), heavy withdrawal bleeding (2.0%), and nausea (2.0%). Cycle control also improved over time, with unscheduled bleeding dropping from 34.5% in cycle 1 to 20.0% by cycle 13.

Comparing Contraceptive Methods

Other birth control methods, such as hormonal birth control pills, carry adverse effects including nausea, headaches, irregular periods, breast tenderness, and increased risk of blood clots.² For comparison, barrier methods such as condoms and diaphragms range from 75% to 91%, and all hormonal methods are at least 99% effective when used properly. Fertility awareness, or natural family planning, is another method that relies on tracking ovulation to determine when intercourse is least likely to result in pregnancy. This method is up to 90% effective when used correctly; however, failure rate is roughly 25%, and effectiveness decreases in women with irregular menstrual cycles. Emergency contraception, such as the morning-after pill, is another option that is available over the counter and is up to 90% effective if taken before ovulation, though it can cause menstrual irregularities.

Continued Need for Variety in Preventing Pregnancies

Viatris expects Gwyn Lo to be commercially available later in 2026, adding another hormonal option for women. Unintended pregnancy remains a significant public health issue in the US, accounting for 41.6% of pregnancies in 2019, according to National Center for Health Statistics data cited in the release.³

Contraceptives play a crucial role in prevention, particularly when options align with patients' needs and preferences: a related 2023 CDC survey found that 18.1% of women aged 18 to 49 who had sex with a male partner had changed or stopped their birth control method in the last 12 months, and the most common reason for 42.8% of women among this group was that they did not like the method they had been using.⁴

References

1. Viatris Inc. Viatris receives U.S. FDA approval for Gwyn Lo, a once-weekly contraceptive patch. News release. Viatris Inc. Published July 29, 2026. Accessed August 3, 2026. https://newsroom.viatris.com/2026-07-29-Viatris-Receives-U-S-FDA-Approval-for-Gwyn-Lo-TM-,-a-Once-Weekly-Contraceptive-Patch
2. Bonavitacola J. 5 birth control methods that are safe for women to use. AJMC®. October 17, 2025. Accessed August 3, 2026. https://www.ajmc.com/view/5-birth-control-methods-that-are-safe-for-women-to-use
3. Rossen LM, Hamilton BE, Abma JC, Gregory ECW, Beresovsky V, Resendez AV, et al. Updated methodology to estimate overall and unintended pregnancy rates in the United States. Vital Health Stat 2. 2023;(201). doi:10.15620/cdc:124395
4. National Center for Health Statistics. Contraception use. NCHS Rapid Surveys System. Centers for Disease Control and Prevention. Updated April 29, 2024. Accessed August 3, 2026. https://www.cdc.gov/nchs/rss/round2/contraception-use.html