Can Mounjaro Cause Depression? What the Evidence Actually Shows

The weight of current evidence actually suggests the opposite — that tirzepatide may have a neutral to beneficial effect on mood in most people. But the picture is nuanced, some people do report mood changes, and understanding why is important before you start treatment.

This article sets out exactly what we know, what we do not yet know, and what to do if you notice changes in how you feel while on Mounjaro.

Mounjaro (tirzepatide) is a weekly injectable medication that works by activating two gut hormone receptors: GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). These hormones regulate appetite, blood sugar, and digestion — but they are also found in the brain.

GLP-1 receptors are present in regions of the brain that govern mood, motivation, and reward — including the hypothalamus, hippocampus, and the brain’s dopamine pathways. This is why researchers have paid close attention to whether GLP-1 medications might interact with mental health. It is not an unreasonable question. It is a scientifically important one.

The concern gained public attention in 2023 when the European Medicines Agency (EMA) launched a review of GLP-1 medications following reports of suicidal thoughts in some users. That review — which was thorough and included tirzepatide — concluded in 2024 that available evidence does not support a causal association between GLP-1 receptor agonists and suicidal thoughts or self-harm.

So where do the online concerns come from? Partly from genuine anecdotal reports of mood changes that deserve to be taken seriously. And partly from the fact that this class of drug is so new that many people are sharing experiences in real time on social media — often before the research has caught up.

The SURMOUNT programme — the landmark series of trials that established tirzepatide’s weight loss efficacy — involved thousands of participants across multiple countries. None of the trials identified depression as a common side effect in any of the SURMOUNT trials. In the SURMOUNT-1 trial published in the New England Journal of Medicine, fewer than 0.5% of participants across all tirzepatide doses reported depression or thoughts of suicide as an adverse event — a rate not significantly different from the placebo group.

Crucially, the document does not list depression among the common adverse effects (occurring in 1% or more of patients) in Mounjaro’s UK Summary of Product Characteristics. This is the document that would carry a prominent warning if the clinical trial evidence warranted one.

It is worth noting that the SURMOUNT trials excluded participants with a history of severe psychiatric disorders or recent suicidal ideation. This is standard practice in drug trials — it protects participants and ensures clean data — but it does mean we have limited data on how Mounjaro affects people who are already living with depression. This is an acknowledged gap in the research, and it matters.

Both the EMA and the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) have investigated the question of GLP-1 medications and psychiatric risk.

The EMA’s Pharmacovigilance Risk Assessment Committee completed its review in 2024 and concluded that the data does not support an association between GLP-1 receptor agonists — including tirzepatide — and suicidal thoughts or self-harm. The MHRA continues post-marketing surveillance through its Yellow Card scheme, which allows patients and clinicians to report any suspected side effects of medications.

The FDA in the United States conducted its own evaluation of clinical trial data and safety reports for GLP-1 medications and similarly found no direct causal link to suicidal thoughts or actions.

These are not small reviews. They involved tens of thousands of individual case safety reports and represent the most rigorous safety assessments available.

Beyond the clinical trials, a growing body of real-world evidence is telling a consistent story — one that many people find surprising.

A large 2024 study examining over 1.5 million people with type 2 diabetes or obesity found that those taking GLP-1 medications were actually less likely to develop depression or experience suicidal ideation compared with those not taking them. The protective signal was particularly strong for people using the medications specifically for weight loss.

A 2025 study published in Frontiers in Psychiatry examined the association between tirzepatide specifically and suicidal ideation or attempts in a real-world cohort. The researchers found that patients treated with tirzepatide showed a significant reduction in suicide risk compared to those on other anti-obesity medications. The authors proposed several biological mechanisms: tirzepatide’s dual GLP-1 and GIP receptor agonism may exert neuroprotective effects by modulating neuroinflammation, the brain’s stress response system, and neurotransmitter pathways that regulate mood.

A 2025 case report published in the Journal of Clinical Psychiatry described two patients — including a 36-year-old woman with major depressive disorder — whose mood improved in a dose-dependent way with tirzepatide. When her dose was lowered, her mood worsened; when it was increased, it improved again. The authors noted these were the first published cases documenting a potential direct mood benefit from tirzepatide, independent of weight loss.

Separate pharmacovigilance analysis found that while semaglutide (Ozempic, Wegovy) showed a statistical signal for depression reports in post-marketing data, tirzepatide did not — despite causing similar or greater weight loss and similar gastrointestinal side effects. This distinction between the two medications is clinically significant and generally underreported in media coverage.

The research does not support the idea that Mounjaro chemically causes depression in the majority of people. But some women do report feeling flat, low, or emotionally different on tirzepatide — and these experiences are real and deserve to be understood, not dismissed.

There are several plausible explanations that do not require a direct pharmacological link.

Rapid weight loss and emotional adjustment.

Losing weight quickly — which Mounjaro facilitates — is a significant physiological change. UK research involving nearly 2,000 overweight adults found that those who lost 5% or more of their body weight over four years were more likely to report low mood than those whose weight remained stable. This does not mean weight loss causes depression — but it does mean that the process of transformation is not always emotionally straightforward.

The loss of food as an emotional tool.

For many women, food has served as a coping mechanism, a source of comfort, or a social pleasure. Mounjaro dramatically reduces appetite and what users describe as “food noise” — the constant mental preoccupation with eating. When that disappears, some people feel a sense of loss or flatness, not because the drug is causing depression, but because a habitual emotional crutch has been removed and nothing has yet replaced it. This is an important psychological transition that benefits from support.

Gastrointestinal side effects affecting mood.

Nausea, reduced appetite, and digestive discomfort — particularly in the first weeks of treatment and after dose increases — are physically draining. Chronic physical discomfort of any kind can lower mood, particularly if it disrupts sleep or daily life. These side effects typically ease as the body adjusts to tirzepatide.

Underlying mood conditions being unmasked.

Women with obesity have significantly higher baseline rates of depression than the general population — independent of any medication. If someone begins Mounjaro while experiencing pre-existing low mood, it can be difficult to know whether any subsequent change in mental health is related to the drug, the underlying condition, or the stress of major lifestyle change.

Dopamine and the reward system.

Tirzepatide’s action on the brain’s reward circuitry — which drives cravings and pleasurable eating — may in rare cases reduce dopamine signalling more broadly. An April 2025 paper identified a potential pathway through which GLP-1 medications might worsen mood in people with a genetic predisposition to low dopamine function. This remains a hypothesis requiring further investigation, but it is a plausible mechanism for the small number of people who do experience emotional blunting on Mounjaro.

Women are disproportionately affected by both obesity-related depression and mood disorders more broadly, which makes this question especially important to answer carefully.

Women account for the majority of Mounjaro users in the UK — research published in 2025 found that use of GLP-1 medications was twice as common in women than in men, and most prevalent in the 45–55 age group. Many women in this demographic are also navigating perimenopause or menopause, which independently affects mood through declining oestrogen levels.

This creates a complex picture. Some mood changes that arise during Mounjaro treatment may have nothing to do with the medication at all — they may reflect hormonal transitions, life circumstances, or underlying mental health conditions that were already present. The importance of a thorough medical assessment before starting treatment, and regular monitoring during it, cannot be overstated.

Women with a personal history of depression, anxiety, eating disorders, or major life stressors should discuss this openly with their prescribing doctor before starting Mounjaro. At CutKilo, Dr Emil Gadimali’s initial consultation includes a full medical and psychological history review precisely because weight loss treatment cannot be approached in isolation from overall wellbeing.

Knowing what mood changes might look like on Mounjaro helps you identify them early and respond appropriately.

Contact your doctor promptly if you notice:

• Persistent low mood lasting more than two weeks
• Loss of interest in things you previously enjoyed
• Emotional flatness or feeling disconnected
• Increased anxiety or irritability
• Changes in sleep — either difficulty sleeping or sleeping much more than usual
• Withdrawal from social activities or relationships
• Appetite changes beyond what Mounjaro would be expected to cause

Seek immediate help if you experience:

• Thoughts of self-harm or suicide

If you experience suicidal thoughts at any point, this is a medical emergency. Contact your GP, call 111, attend your nearest A&E, or call the Samaritans on 116 123. Do not stop Mounjaro without medical advice first — but do not delay seeking help.

Most people on Mounjaro will not experience any of these symptoms. But awareness is protective.

Doctor-led care matters here precisely because Mounjaro is not just a physical treatment — it intersects with how you feel, how you relate to food, and how you see yourself. These things require human attention, not just a prescription.

At CutKilo, every patient has access to Dr Emil Gadimali on an ongoing basis, as well as dietitian Hanna Baldursdottir, who provides nutritional guidance that directly supports mood — adequate protein, micronutrients, and hydration all play a role in mental health alongside weight management. Monthly check-ins allow any mood changes to be caught early and addressed before they become significant.

This is the fundamental difference between a doctor-led programme and an online pharmacy. The medication is the same. The care around it is not.

Is depression a listed side effect of Mounjaro? Depression is not listed as a common side effect in Mounjaro’s UK prescribing information. The label carries a general note about mood changes — primarily in the context of hypoglycaemia (low blood sugar) — but trial data does not identify depression based on trial data.

Does Mounjaro affect serotonin or dopamine? Tirzepatide’s GLP-1 and GIP receptors are found in brain regions involved in mood and reward. There is emerging evidence that it may modulate neurotransmitter pathways, and some research suggests a potential mood benefit via these mechanisms. However, this science is still developing.

I felt emotionally flat after starting Mounjaro. Is this normal? Some people describe a period of emotional adjustment after starting Mounjaro, particularly related to the loss of food noise and changes in appetite. This is not the same as clinical depression, but it is a real experience worth discussing with your doctor. If it persists or worsens, seek advice.

Is Mounjaro safe for women with a history of depression? Women with a history of depression are not automatically excluded from Mounjaro. However, they should be open with their prescribing doctor about their mental health history so that appropriate monitoring is in place. Close oversight in the first months of treatment is particularly important.

Can Mounjaro actually improve mood? There is growing evidence — including real-world studies and case reports published in 2025 — that tirzepatide may have mood-stabilising or even antidepressant-like effects in some patients. This is thought to be related to its anti-inflammatory properties, neuroprotective effects, and influence on the brain’s reward and stress systems. This is an active area of research.

If you are considering Mounjaro and want to discuss whether it is right for you — including any mental health history — speak to Dr Emil Gadimali at CutKilo. Every patient receives a thorough medical assessment before treatment begins. Get started at cutkilo.com or email info@cutkilo.com.

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