GLP-1 and Fertility: What Men and Women Should Know Before Starting Treatment

May 24, 2026

GLP-1 and Fertility: What Men and Women Should Know Before Starting Treatment

By Dr. Onikepe Adegbola, MD PhD — Johns Hopkins-trained physician-scientist and founder of Casa de Sante

Key Takeaways

GLP-1 medications can significantly impact fertility — both positively and in ways that require careful planning. Weight loss from GLP-1 can IMPROVE fertility in overweight/obese individuals by restoring ovulation, normalizing hormones, and improving sperm parameters.
However, GLP-1 medications are NOT approved for use during pregnancy. All GLP-1 medications carry a pregnancy warning. Semaglutide should be stopped at least 2 months before planned conception (due to its long half-life). Tirzepatide should be stopped at least 1 month before.
The "Ozempic baby" phenomenon is real: many women on GLP-1 become pregnant unexpectedly because weight loss restores ovulation in women who weren't ovulating. If you're on GLP-1 and sexually active, use reliable contraception.
GLP-1 may reduce oral contraceptive effectiveness by slowing gastric emptying → altered absorption → breakthrough ovulation.

GLP-1 and Female Fertility

How Weight Loss Restores Fertility

Excess body fat disrupts the hypothalamic-pituitary-ovarian (HPO) axis. Fat tissue produces excess estrogen through aromatization → suppresses FSH/LH → anovulation.
Losing just 5-10% body weight restores ovulatory cycles in 60-80% of anovulatory obese women.
GLP-1 typically causes 15-20% weight loss → dramatic fertility improvement in overweight women.
PCOS patients benefit particularly: weight loss reduces insulin resistance → decreases androgen production → normalizes menstrual cycles → restores ovulation.

The "Ozempic Baby" Phenomenon

Women who haven't been ovulating (and thought they couldn't get pregnant) suddenly begin ovulating on GLP-1.
If relying on their prior infertility as birth control → unexpected pregnancy.
Additionally, GLP-1 may reduce the absorption of oral contraceptives. The delayed gastric emptying changes how and when the pill is absorbed. The FDA added a specific warning about this interaction for semaglutide in 2023.
Recommendation: women of childbearing age on GLP-1 should use non-oral contraception (IUD, implant, condoms) or barrier methods IN ADDITION to oral contraceptives.

Pre-Conception Planning

Semaglutide: Stop at least 2 months (8 weeks) before planned conception. The drug's half-life is ~1 week, requiring multiple half-lives for clearance.
Tirzepatide: Stop at least 1 month (4 weeks) before planned conception.
Use this time for nutritional optimization: The 2-month washout period is ideal for building nutritional reserves (folate, iron, calcium, vitamin D) depleted during GLP-1 treatment.
Expect weight regain: Some weight regain is normal after stopping GLP-1. Focus on nutrition quality, not weight, during pre-conception.

GLP-1 and Male Fertility

Positive Effects

Obesity reduces testosterone by 30-40% through increased aromatization (fat converts testosterone to estrogen) and hypothalamic suppression.
Weight loss on GLP-1 can increase testosterone by 100-200 ng/dL. This improves: sperm count, motility, morphology, and libido.
Reduced scrotal fat improves testicular temperature regulation → improved spermatogenesis.

Potential Concerns

Extreme caloric restriction can transiently suppress the HPG axis in men → temporary reduction in sperm production.
Nutritional deficiencies (zinc, selenium, folate, omega-3) from reduced food intake can impair sperm quality.
Moderate weight loss (1-2 lbs/week) maintains hormonal balance better than extreme rapid weight loss.

Nutritional Support for Fertility on GLP-1

For Women

Folate (800mcg daily): Required for neural tube development. Start 3 months before planned conception. Critical because GLP-1's reduced food intake may have depleted stores.
Iron: Pregnancy iron demands are enormous. Ensure ferritin is above 50 ng/mL before conception.
Vitamin D: Associated with improved implantation rates and pregnancy outcomes. Target 40-60 ng/mL.
DHA/EPA: Essential for fetal brain development. Start supplementation pre-conception.
Protein adequacy: 1.0-1.2g/kg daily. Adequate protein supports egg quality and hormonal function.

For Men

Zinc: Essential for testosterone production and sperm development. 30mg daily.
Selenium: Required for sperm motility. 200mcg daily.
Folate: Yes, men too. Folate is important for sperm DNA integrity. 400mcg daily.
CoQ10: Improves sperm motility and protects sperm from oxidative damage. 200-400mg daily.
Omega-3: DHA is concentrated in sperm membranes and essential for sperm function.

🛒 Fertility Nutrition Support

Daily Vitamin — Contains the fertility-critical nutrients depleted by GLP-1: folate, iron, zinc, selenium, vitamin D, and B vitamins. Start during GLP-1 treatment and continue through the pre-conception period. Correcting micronutrient deficiencies before conception is one of the most impactful things you can do for fertility and a healthy pregnancy.
Whey Protein — Maintains protein intake during the transition off GLP-1. Adequate protein supports: ovarian function (women), testosterone production (men), and provides the amino acids needed for reproductive hormone synthesis. Easy to consume even when appetite is adjusting post-GLP-1.
Collagen Peptides — Glycine from collagen supports glutathione production — critical for protecting both egg and sperm from oxidative damage. Glycine is also a major amino acid in the uterine lining. Collagen supports the structural integrity of reproductive tissues.

Medical Disclaimer: This article is for educational purposes only. If you become pregnant while on GLP-1, contact your prescriber IMMEDIATELY to discontinue the medication. GLP-1 is Category X in some frameworks. Do not attempt to use GLP-1 for weight management during pregnancy. If you're trying to conceive, work with a reproductive endocrinologist who can coordinate GLP-1 discontinuation with your fertility plan. Dr. Adegbola is the founder of Casa de Sante.

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