GLP-1 weight loss medications and HRT

The use of GLP-1/GIP weight management medications alongside Hormone Replacement Therapy (HRT), including semaglutide (Wegovy®), liraglutide (Saxenda®) and tirzepatide (Mounjaro®).

Why GLP-1 medications may affect oral HRT

GLP-1 medicines work by helping appetite control and improving metabolic regulation. One of their actions is to slow stomach emptying (delayed gastric emptying).

Because of this, GLP-1 medicines can sometimes cause side effects such as:

• Nausea
• Vomiting
• Diarrhoea
• Constipation
• Reduced absorption of medicines taken by orally (in some cases)

Because they slow digestion, they may also reduce the absorption of oral medicines, including HRT, particularly when:

• GLP-1 is being started, or doses increased
• Patients experience vomiting or diarrhoea
• There is significant delayed gastric emptying

This is most relevant for oral hormone preparations, because their effect relies on consistent absorption through the gut.

The British Menopause Society highlights that the main concern is ensuring that women who still have a uterus receive enough progesterone/progestogen for endometrial (womb lining) protection, as reduced absorption could increase the risk of unscheduled bleeding and (in higher-risk groups) endometrial problems. [1]

What this means for your HRT

• Oestrogen

If you take oestrogen as a tablet by mouth, the absorption may be affected, if you have delayed gastric emptying, diarrhoea or vomiting. In these situations, the body may absorb less hormone, meaning you may experience:

• Return of menopausal symptoms (hot flushes, night sweats)
• Mood changes
• Irregular/breakthrough bleeding (if taking combined HRT)

If your oestrogen is already a patch/gel/spray, absorption should not be affected.

• Progesterone/Progestogen (womb protection)

The largest concern relates to oral progestogen/progesterone (tablets taken by mouth), as absorption may be affected during:

• Starting GLP-1 therapy, and
• Each dose escalation (dose increase)

It is advised to consider:

• Using a non-oral method of womb protection, or
• Temporarily increase oral progesterone/progestogen for 4 weeks after starting, and for 4 weeks after each dose increase, until the dose becomes stable. 

Please speak to your GP regarding dose escalation.

Our clinical recommendation

To ensure consistency and avoid reduced absorption, our recommendation (aligned with FSRH guidance) is:

• If you are using GLP-1 medication and require HRT, consider:

• Transdermal oestrogen, as first choice
• Progesterone via Mirena® or other non-oral options, where appropriate
• Local vaginal oestrogen, if needed for urogenital symptoms

This approach ensures that menopausal symptom control remains stable and is not disrupted by digestive side effects.

If you take oral HRT, it may be preferable to switch to a more reliable HRT delivery system.

• Non-oral HRT (preferred option) is a more reliable approach where hormones do not rely on gut absorption. This includes:

• Transdermal oestrogen patches
• Transdermal oestrogen gel / spray
• Mirena® (LNG-IUS) for progesterone / endometrial protection
• Vaginal oestrogen (local therapy)

These options are not affected by vomiting/diarrhoea or delayed gastric emptying and are considered more stable and reliable alongside GLP-1 medicines.

This is especially relevant during:

• the first 4 weeks after starting GLP-1, and/or
• after each dose increase (titration)

Important Information: HRT is NOT contraception

It is important to note:

• HRT does not act as contraception
• GLP-1 medicines may restore fertility in some individuals due to weight loss and/or hormonal regulation
• There is therefore a risk of pregnancy, even if periods have been absent or irregular

If there is any chance of pregnancy and you are sexually active, you should ensure you have effective contraception, and we can advise accordingly.

What to do if you have vomiting or diarrhoea

If you are using oral HRT and you have vomiting/diarrhoea:

• If you vomit within a few hours of taking oral HRT, absorption may be reduced
• If diarrhoea is severe or lasts more than 24 hours, absorption may be reduced

If this happens repeatedly, we advise switching to patch/gel (more reliable).

When to Seek Medical Advice

Please contact your GP as soon as possible if you experience:

• Persistent vomiting or diarrhoea
• Unexpected bleeding
• Significant return of menopausal symptoms
• Concerns about contraception/pregnancy risk

Important Safety Advice

It is important to use GLP-1 medications safely and in line with clinical guidance.

Maintaining open communication with your provider is key to ensuring safe and effective treatment.

Remember:

• Do not ignore persistent or worsening symptoms
• Do not increase or stop your medication without advice
• Ensure your GP is informed of any new or unusual symptoms

Additional support

If you are experiencing side effects or have any questions about your treatment, our clinical team is here to help.

If your symptoms are severe, worsening, or you feel they require urgent medical attention, please seek immediate advice from your GP, NHS 111, or attend your nearest A&E department if appropriate.

For all other queries:

• Book a free video consultation with one of our trained clinicians through our website. Appointments are available throughout the week, including daytime and evening sessions.
• Send us your question online using our form: https://forms.medicinemarketplace.com/251345635207050 A member of our clinical team will respond by email.
• Speak to us by phone by calling 0330 175 5747, and selecting option 3.

We are here to answer your questions and provide support throughout your treatment journey.

Reference

[1] Progestogens and endometrial protection (Accessed: 7 July 2026) https://thebms.org.uk/wp-content/uploads/2026/05/14-NEW-BMS-TfC-Progestogens-and-endometrial-protection-MAY2026-A.pdf 

Written by: Uzma Dala MPharm (2238839)

Approved by: Shameela Adam MPharm (2070113)