Tesamorelin side effects and risks

Reported side effects

• Injection-site redness, itching or pain: All injection site reactions: 25% versus 14% placebo over 26 weeks., mild. Rotate abdominal sites; seek care for spreading redness, warmth, pus or fever. (source)
• Joint pain: 13% versus 11% placebo in the pooled 26 week adverse reaction table., moderate. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• Muscle pain: 6% versus 2% placebo., moderate. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• Swollen ankles or other fluid retention: 6% versus 2% placebo., moderate. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• Arm or leg pain: 6% versus 5% placebo., moderate. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• Tingling: 5% versus 2% placebo., moderate. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• Reduced skin sensation: 4% versus 2% placebo., moderate. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• Rash: 4% versus 2% placebo., mild. A rash with breathing trouble, facial swelling or faintness needs emergency care. (source)
• High blood sugar or new diabetes: HbA1c ≥6.5% developed in 5% versus 1% placebo by week 26., serious. Check glucose; the label advises reassessing treatment if glucose worsens without clear benefit. (source)
• Allergic reaction: 4% of tesamorelin trial participants; the warning gives no placebo rate., serious. Stop and seek prompt medical attention; use emergency care for breathing or circulation symptoms. (source)
• Carpal tunnel syndrome: 1% versus 0% placebo in the pooled adverse reaction table., moderate. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• Vomiting: 3% versus 0% placebo., moderate. Persistent vomiting needs review and assessment of hydration. (source)
• Stomach discomfort: Indigestion: 2% versus 1% placebo., mild. Discuss persistent symptoms and reassess the dose or need for treatment. (source)
• High IGF-1: IGF 1 >3 standard deviations above the age average: 36% at 26 weeks; 23% at 52 weeks among continuing patients., moderate. Monitor IGF-1; the label advises considering stopping if levels stay this high. (source)

Stop and get help if

• Trouble breathing, swelling of the face or tongue, widespread hives or faintness: Stop dosing and get emergency care now.
• New severe breathlessness, chest pain, fainting or rapidly worsening swelling: Get urgent medical care now; severe symptoms need emergency services.
• Marked thirst or frequent urination with vomiting, confusion or deep breathing: Check glucose if available and get urgent care for possible severe high blood sugar.
• New blurred vision, sudden vision loss or a curtain over vision: Get same-day eye assessment; sudden vision loss is an emergency.
• Spreading injection-site redness, heat, pus or fever: Stop using that vial and get prompt care for possible infection.

Who should avoid it

• pregnant: Contraindicated by the label. Changing pregnancy-related visceral fat has no known benefit and may harm the fetus.
• tryingToConceive: Listed as a reason to avoid it.
• breastfeeding: No human milk or infant-safety data. The product label says mothers receiving tesamorelin should not breastfeed.
• under18: Safety and effectiveness are not established; the label does not indicate pediatric use.
• activeCancer: Contraindicated because tesamorelin raises GH and IGF-1. Stop if a prior cancer recurs.
• cancerHistory: Past cancer must be inactive with treatment complete; review the possible risk of recurrence before starting.
• other: Contraindicated with pituitary-axis disruption, including pituitary tumor or surgery, head irradiation, hypopituitarism or relevant head trauma.
• other: Contraindicated after a known allergy to tesamorelin or an ingredient in the specific product.
• diabetes: New diabetes can develop. Existing diabetes needs glucose follow-up and retinal monitoring.
• diabeticRetinopathy: Raised IGF-1 may worsen retinal disease; the label calls for regular monitoring in people with diabetes.
• kidneyDisease: Drug levels and needed dose changes with kidney impairment are unknown.
• liverDisease: Drug levels and needed dose changes with liver impairment are unknown, including in advanced liver failure.
• heartCondition: Fluid retention may worsen swelling or heart-failure symptoms; long-term cardiovascular safety is unknown.
• surgeryPlanned: Critical illness after major surgery or trauma warrants reassessment; the label advises considering discontinuation in critically ill patients.
• other: Consider stopping during sudden breathing failure or severe critical illness. The warning comes from growth hormone drug treatment.
• testedAthlete: Prohibited at all times under the 2026 WADA List, section S2.2.4.

Interactions

• Insulin and sulfonylureas: Tesamorelin may raise blood sugar and change medication needs. Watch for highs or lows after diabetes medicines change.
• Glucocorticoid replacement: Growth hormone can reduce cortisone's conversion to cortisol. Clinicians may review routine or stress steroid replacement.
• Other growth hormone and IGF-1 drugs: May add to effects on blood sugar, swelling and tissue growth. Combination safety is unknown.
• Cyclosporine and some seizure medicines: Growth hormone may change drug breakdown. Clinicians can check drug effects and blood levels.
• Sex steroids: The label warns sex hormone breakdown may change. A clinician should review possible interactions.
• Simvastatin and ritonavir: Small crossover studies in healthy volunteers found no drug level changes requiring dose adjustment.
• Anticoagulants: No direct interaction is established. Injections can bruise; review medicines with a clinician if bleeding risk is high.

Product quality risks

• An FDA-approved molecule does not make an online vial an approved product. Identity, amount and injectable quality may differ.
• Poor preparation can cause contamination or too much or too little active drug; FDA describes serious injury and death from compounding failures.
• No independent tesamorelin retail-sampling study or drug-specific counterfeit-pen series was found. Do not borrow semaglutide contamination rates.
• A purity percentage alone does not establish the dose, sterility, endotoxin level or stability after mixing.