Based on NIH | Is weight loss a known side effect of losartan, and should I be concerned if I lose weight while taking it?

Weight loss is not a typical side effect of losartan (an angiotensin II receptor blocker used for high blood pressure). The most commonly reported side effects include dizziness, upper respiratory symptoms (“colds”), stuffy nose, and back pain, and consumer and professional labeling highlight “unexplained weight gain” as a warning sign to contact a clinician, rather than weight loss. ^{[1] [2]} Weight change is not listed among common adverse effects in clinical trials, and overall tolerability is similar to placebo, with dizziness being the main symptom seen slightly more than placebo. ^[3] In standard dosing studies, there were no significant changes in body weight compared with placebo, supporting that loss of weight is not expected from losartan alone. ^[4]

What official labeling and studies say

• Losartan’s consumer and professional guides list typical side effects (dizziness, colds/stuffy nose, back pain) and advise calling your doctor for swelling or unexplained weight gain, especially if you have kidney problems. ^{[1] [2]}
• Large randomized trials and pooled safety data show losartan is generally well tolerated, with adverse events comparable to placebo and no consistent signal for weight loss. ^[3]
• Ambulatory blood pressure monitoring trials note no significant changes in body weight across dosing regimens, reinforcing that weight loss is not a recognized effect. ^[4]

Could losartan indirectly contribute to weight loss?

While losartan itself is not known to cause weight loss, a few indirect scenarios could make weight change more noticeable:

• Dizziness or fatigue might reduce activity temporarily, but this typically wouldn’t cause weight loss; when present, dizziness is usually mild and transient. ^[3]
• Rare appetite changes are mentioned among “incidence not known” side effects in general drug references for losartan, but this is not consistently reported in clinical trials or official labeling and should prompt evaluation if persistent. ^[5]
• Combination therapy with hydrochlorothiazide (a diuretic) can increase urination and lower fluid retention, but controlled trials did not show clinically significant body weight reductions attributable to losartan or the combination in the short term. ^[6]

When to be concerned

Unintentional weight loss can signal an underlying issue (for example, thyroid problems, gastrointestinal conditions, chronic infections, mood changes, or malignancy), so it’s wise to monitor and discuss it. A practical threshold many clinicians use is more than 5% of body weight lost over 6–12 months without trying. ^[7] If you notice steady weight loss you did not intend, you should reach out to your healthcare provider, as they may recommend an evaluation and adjust treatment if needed. ^[8] If you are on blood pressure medicines and experience weight loss or gain without trying, you should inform your provider so they can review medications and look for other causes. ^[9]

What to do next

• Track your weight weekly and note any related symptoms (appetite changes, nausea, bowel changes, fevers, sweats, tremor, palpitations). This helps your clinician pinpoint possible causes. ^[8]
• Review all medications and supplements with your clinician, including any recent changes. Most losartan users do not experience weight loss, so persistent loss suggests looking beyond this medicine. ^[3]
• Seek care sooner if weight loss is accompanied by red flags such as persistent vomiting, severe fatigue, night sweats, fever, or swelling. While losartan labeling focuses on unexplained weight gain as a warning sign for kidney issues, any significant unintended weight change merits attention. ^{[1] [2]}

---

Summary table: Losartan and weight change signals

Topic	What’s typical	What needs action
Common losartan side effects	Dizziness, upper respiratory symptoms, stuffy nose, back pain	Usually mild; discuss if persistent or bothersome [1] [2]
Weight loss	Not a recognized common effect; trials show no significant change	Evaluate if >5% unintentional loss over 6–12 months [3] [4] [7]
Weight gain	“Unexplained weight gain” flagged, especially with edema (swelling)	Call clinician to check kidney function and fluid status [1] [2]
Combination with diuretic (HCTZ)	Additive BP lowering; no significant adverse differences	Monitor hydration and electrolytes; report unusual changes [6]

In short, losartan is not known to cause weight loss, and if you are losing weight without trying, it’s reasonable to speak with your clinician to look for other causes and to ensure your treatment plan remains safe and effective. ^{[3] [4] [7] [8] [9]}