Losartan and Weight Gain: What the Evidence Shows

Losartan (brand name Cozaar) is an angiotensin II receptor blocker (ARB) commonly prescribed for high blood pressure and certain kidney and heart conditions. Reports of weight gain with losartan are uncommon, but this effect has been observed and is listed among adverse reactions in product labeling. The consumer and professional labels also advise contacting a clinician for unexplained weight gain because it can signal fluid retention, especially in people with kidney issues. ^{[1] [2]}

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Does Losartan Cause Weight Gain?

• Possible but uncommon: Losartan’s official labeling includes “weight gain” as an adverse reaction reported during clinical experience. The label groups it under metabolic and nutrition events, indicating it has occurred, though not among the most frequent side effects like upper respiratory infection or dizziness. ^{[3] [4]}
• A warning sign of fluid retention: The consumer safety information advises calling a healthcare provider if you develop swelling in the feet, ankles, or hands, or have unexplained weight gain, because this may indicate worsening kidney function or fluid buildup. ^{[1] [5]}

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How Common Is Weight Gain With Losartan?

• Listed but not highlighted as common: In pooled adverse event tables from losartan labeling, “weight gain” appears under metabolic and nutrition reactions that were observed, whereas common side effects highlighted for hypertension include colds (upper respiratory infection) and dizziness. This suggests weight gain is less frequent compared with the most common effects. ^{[4] [1]}
• Clinical trial context: Across large controlled trials, losartan has generally shown an adverse event profile similar to placebo, with dizziness being the most frequent patient‑reported event above placebo; weight gain was not highlighted as a common signal in those summaries, aligning with it being relatively uncommon. ^[6]

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Why Might Weight Change Occur?

• Fluid retention (edema): Unexplained weight gain together with swelling can reflect fluid accumulation, which may be linked to kidney function changes; losartan labeling specifically flags this scenario for prompt medical review. This does not mean losartan typically causes edema, but any new edema and weight gain deserves attention. ^{[1] [5]}
• Metabolic shifts are not typical: ARBs, including losartan, are generally not associated with broad, consistent weight-increasing effects in adults in clinical studies, and losartan is often well tolerated. ^[6]

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What To Watch For

• Seek care for rapid changes: Sudden weight gain (for example, more than 2–3 pounds in a day or 5 pounds in a week) with ankle or hand swelling, shortness of breath, or decreased urination should prompt medical evaluation to rule out fluid retention or kidney issues. The label specifically advises contacting your doctor for unexplained weight gain or swelling. ^{[1] [5]}
• Track symptoms: Keep a daily weight log, note any swelling, and monitor blood pressure and urine output; bring this information to your appointment. These details help your clinician assess whether the change is medication‑related or due to another cause. ^[1]

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Practical Guidance

• Do not stop losartan on your own: Because losartan reduces cardiovascular risk by lowering blood pressure, stopping it abruptly can be harmful; discuss any concerns with your clinician. Your prescriber may check kidney function and electrolytes and consider dose adjustment or alternative therapy if needed. ^[2]
• Consider other factors: Lifestyle changes, diet, salt intake, other medications (especially those that cause fluid retention), and underlying health conditions can contribute to weight changes; your clinician will review these alongside lab tests.

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Key Takeaways

• Weight gain can occur with losartan but appears uncommon. It is recognized in product labeling, primarily as an observed adverse reaction rather than a common side effect. ^{[3] [4]}
• Unexplained weight gain with swelling is a red flag that should prompt you to contact your healthcare provider, as it may reflect fluid retention or kidney function changes. ^{[1] [5]}
• Overall tolerability is generally good: In controlled trials, losartan’s adverse event rates were similar to placebo, and dizziness was the most frequent event above placebo. ^[6]

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Adverse Events Snapshot

The following table summarizes how “weight gain” is represented relative to other adverse reactions in losartan labeling.

Label section	Noted adverse reactions	Notes
Consumer/professional guidance	“Call your doctor if you get swelling in your feet, ankles, or hands, or unexplained weight gain.”	Emphasizes evaluation for potential kidney issues or fluid retention. [1] [5]
Adverse event listings	Metabolic and nutrition: includes “weight gain” among reported events	Indicates occurrence but not identified among the most common side effects. [3] [4]
Common side effects (hypertension)	Upper respiratory infection (“colds”), dizziness, stuffy nose, back pain	Weight gain is not listed among the most common events in hypertension trials. [2]

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If you’ve noticed recent, unexplained weight gain while on losartan especially with swelling would you like help reviewing your symptoms and current dose?