A 39‑year‑old man injected a very high dose of Melanotan II (6 mg, six times the recommended start) and quickly developed dangerous symptoms like fast heart rate, anxiety, sweating, muscle tremors, and later severe muscle breakdown (rhabdomyolysis) that hurt his kidneys. He was treated with calming meds, lots of IV fluids, and bicarbonate, which helped his labs improve. This case shows that taking too much Melanotan II can cause serious, life‑threatening side effects.

Melanotan products are currently purchased over the Internet and are designed to induce melanogenesis to create sunless tanning as well are used as sexual stimulants. We report a novel case of systemic toxicity with sympathomimetic excess and rhabdomyolysis after use of Melanotan II. A 39 year-old Caucasian male injected subcutaneously 6 mg of Melanotan II purchased over the Internet in an attempt to darken his skin during wintertime. This dose was six times the recommended starting dose per the patient. In the emergency department two hours post injection, he complained of diffuse body aches, sweating, and a sensation of anxiety. Vital signs included BP 151/85 mmHg, HR 130 bpm that peaked at 146 bpm, and temperature of 97.8°F. Physical exam demonstrated a restless and anxious appearing male with mydriasis, diaphoresis, tachycardia, and diffuse muscle tremors. Pertinent laboratory values were creatinine 2.25 mg/dL, CPK 1760 IU/L, troponin 0.23 ng/mL, WBC 19.1 k/μL. Urinalysis demonstrated 3 + blood with red cell casts but 0-2 RBC/hpf. Qualitative urine drug screen was negative for metabolites of cocaine and amphetamines but positive for opiates. The patient received benzodiazepines for agitation and anxiety and had improvement in his symptoms. He was admitted to the ICU and during hospitalization his CPK elevated to 17773 IU/L 12 hours later. He continued to receive intravenous fluids with sodium bicarbonate for rhabdomyolysis and his CPK decreased to 2622 IU/L with improvement of creatinine to 1.23 mg/dL upon discharge from the ICU after 3 days. The substance, which he injected, was analyzed via mass spectrometry and was confirmed to be Melanotan II when compared with an industry purchased standard sample. Melanotan products are purchased via the Internet and have three main formulations (Melanotan I, Melanotan II, and bremelanotide). Melanotan I increases melanogenesis and eumelanin content to produce sunless tanning. Melanotan II also increases skin pigmentation but also produces spontaneous penile erections and sexual stimulation. Bremelanotide is a variation of Melanotan II that is specifically designed for sexual stimulation. This unique case highlights the potential of systemic toxicity with sympathomimetic excess, rhabdomyolysis, and renal dysfunction from Melanotan II use. Melanotan II use resulted in systemic toxicity including apparent sympathomimetic symptoms, rhabdomyolysis, and renal dysfunction.