Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Although not all side effects are known, 5-HTP is thought to be possibly safe when taken for a short period of time.
Stop using 5-HTP and call your doctor at once if you have:
severe tingling or numbness;
skin rash, bruising, fever; or
muscle pain or weakness.
Common side effects may include:
drowsiness;
nausea, vomiting, stomach pain, heartburn;
diarrhea; or
loss of interest in sex.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
 5-HTP side effects (more detail)
