Can You Take Weight Loss Injections With Antidepressants? (October 2026)

01 · Your decision

Should you take an injection if you are on an antidepressant?

That decision belongs with a prescriber who can see your full medicine list. What matters is which medicines you take, your health history and how stable you currently feel.

If you already take an antidepressant, the practical steps are simple:

• Keep taking your antidepressant exactly as prescribed.
• List it, with any other medicines, in the consultation.
• Mention any past or current low mood, anxiety or eating difficulties.
• Ask your own GP or mental health team if you are unsure.

Our consultation is free, with no obligation, and is reviewed by a GPhC-registered prescriber.

Related guide: Weight Loss Injections Register Online.

02 · What we can and cannot say

How Mounjaro works and where to find its cautions

Mounjaro activates the GIP and GLP-1 receptors, which helps regulate appetite and slows how quickly the stomach empties. The full list of cautions sits in the patient information leaflet, which every user should read.¹³

For a deeper look at specific pairings, see our guides on Mounjaro with antidepressants, antidepressants with GLP-1 medicines and antidepressants and weight loss medication.

03 · Antidepressants and weight

Antidepressants and weight: why results differ

Antidepressants affect people's weight in different ways, and the effect depends on the individual and the medicine. Some people notice a change in appetite, others notice nothing. That is why a struggle to lose weight on an antidepressant is worth raising with your GP rather than assuming it is your fault.

Our guide explains whether antidepressants are appetite suppressants. Do not switch or stop an antidepressant to chase weight loss. Any change should be agreed with the doctor who prescribed it, because stopping suddenly can cause problems.

04 · If you feel different

What to do if you notice new symptoms

Tell your prescriber if your mood, sleep or anxiety changes after starting any weight loss injection. Do not wait for your next review. If you have thoughts of harming yourself or ending your life, get help straight away. Call 999 or go to A&E if you are in immediate danger. In England you can call NHS 111 and choose the mental health option, any time. You can also call Samaritans free on 116 123, day or night. Tell your prescriber about any change in your mood while taking Mounjaro. You can also report a suspected side effect through the Yellow Card scheme.¹⁹

Our aftercare includes ongoing monthly reviews, dose-titration support and side-effect support from the prescribing team. Repeat orders re-check suitability, and nothing ships automatically.

05 · What to expect from treatment

What to expect from treatment

Weight loss on Mounjaro is gradual by design, and everyone starts on 2.5mg to let the body adjust. Your prescriber reviews progress, and the pace should never be rushed. Mood and wellbeing matter as much as the scales, so say how you are feeling at every review.

06 · Serious side effects

Serious side effects: when to get help straight away

Serious side effects are uncommon but need urgent attention. Seek immediate medical help for: severe, persistent stomach pain that may spread to your back, with or without vomiting (possible pancreatitis); pain in the upper right abdomen, fever or yellowing of skin/eyes (possible gallbladder problems); or signs of a severe allergic reaction such as swelling of the face or throat and difficulty breathing. If you take insulin or a sulfonylurea alongside Mounjaro, watch for low blood sugar (shakiness, sweating, confusion) — your prescriber may need to adjust those medicines.¹