Medicine Interaction Alert

Weight Loss Injections & HRT/Contraception

Important: This practice does not prescribe weight loss injections. These medications are typically obtained through private clinics or specialist services. If you are taking weight loss injections prescribed elsewhere, please read the important information below.

Understanding Weight Loss Injections and Progesterone in HRT

If you're using weight loss injections like semaglutide (Wegovy or Ozempic) or tirzepatide (Mounjaro) obtained from private providers or specialist services and also taking progesterone as part of your hormone replacement therapy (HRT), it's important to understand how these treatments may interact.

How They Work:

• Weight loss injections help control appetite and slow stomach emptying, which can lead to reduced food intake and weight loss.
• Progesterone, commonly used in HRT for women with a uterus, helps protect against the risks of oestrogen therapy alone, especially for the uterus lining.

Possible Interaction:

Because weight loss injections slow down how your stomach processes food and medication, they may also affect how oral progesterone is absorbed. This could reduce its effectiveness or cause variations in how your body responds to it.

If you are using weight loss injections and are also taking hormone replacement therapy please submit an online consultation via our website to arrange an appointment for a review.

Weight Loss Injections and Contraception

Are you using weight loss injections from private clinics or other providers?

It is important to use effective contraception whilst taking these injections as these medications should not be used in pregnancy.

Please be aware that these injections can stop the oral contraceptive pill from working correctly, which could put you at risk of unwanted pregnancy. Please see here for more information.

If you would like to discuss this further please submit an online consultation via our website.

Please note: Weight loss injections are not initiated in primary care in South East London.

If you create Weight Management page in self-help section, the below links might be useful:

National

• NHS - Lose Weight

Local

• Guys & St Thomas - Southwark Healthy Weight Programme

Southwark

• Southwark Everyone Health - Weight Management

Published: Jun 25, 2025