Melatonin Does Not Cause Fever
Melatonin does not cause fever and, in fact, has been shown in research to reduce fever and body temperature. There is no evidence in clinical guidelines or research literature linking melatonin supplementation to fever as an adverse effect.
Evidence Against Melatonin Causing Fever
The available research actually demonstrates the opposite relationship:
Animal studies show melatonin attenuates fever: In Siberian hamsters, long-term melatonin exposure reduced fever duration by 32% following bacterial lipopolysaccharide injection, likely as an energy-conservation mechanism 1
Melatonin reverses lipopolysaccharide-induced fever in rats: Research demonstrated that melatonin (2-6 mg/kg) completely reversed fever induced by bacterial endotoxin, potentially by reducing prostaglandin and cytokine formation 2
Documented Adverse Effects of Melatonin
According to clinical practice guidelines, the actual adverse effects associated with melatonin include 3, 4:
- Drowsiness (most common - reported in 28.8% of users) 5
- Headache (25.1% of users) 5
- Increased depressive symptoms (caution advised in patients with depression) 4
- Impaired glucose tolerance (documented in healthy women after acute administration) 4
- Daytime sleepiness
Notably, fever is not listed among the recognized adverse effects in any of the major sleep medicine guidelines from the American Academy of Sleep Medicine 3, 4.
Clinical Recommendation
If a patient develops fever after starting melatonin:
- Look for alternative causes - the fever is almost certainly unrelated to melatonin use
- Evaluate for concurrent infection or other inflammatory processes
- Continue melatonin if clinically indicated for sleep disorders, as there is no contraindication
- Consider that melatonin may actually help reduce fever if present from another cause
Important Caveats
- Melatonin formulations vary significantly in actual content due to limited regulatory oversight as a dietary supplement 3
- The U.S. Pharmacopeia Verification Mark indicates verified dosing accuracy 3
- Melatonin is generally considered safe in the perioperative period and does not require discontinuation 6