Possible side effects of 5-HTP include muscle weakness, tingling, skin rash, bruising, numbness and pain, according to Drugs.com. Less serious side effects include appetite loss, stomach pain, vomiting, nausea, heartburn and gas. Other possible side effects include heartburn, drowsiness, sexual problems and muscle problems.
5-HTP is produced as a protein building block L-tryptophan. It can be used to treat depression and fibromyalgia, and there is little evidence that it can be used to treat other health issues, such as Alzheimer's, anxiety, nervous system disorders, headache, menopausal symptoms and more.
According to WebMD,EMS is a more serious side effect that is often associated with the use of 5-HTP. Some experts connect the use of 5-HTP with EMS due to some ingredients that are found in 5-HTP, such as contaminants. These contaminants are found in certain 5-HTP products and not in others. While this connection with EMS has not been fully proven, it is recommended to take the necessary precautions when taking 5-HTP. Those with Down syndrome should take precautions with 5-HTP, because it has been linked to possible seizures.
Signs of an allergic reaction to the active ingredient in 5-HTP, hydroxytryptophan, include hives, breathing problems and swelling of the face, tongue, throat or lips, states Drugs.com. If serious side effects are experienced, a healthcare provider should be contacted immediately.
Some who have taken 5-HTP have gotten eosinophilia-myalgia syndrome, which is a serious condition that causes muscle tenderness and abnormalities in the blood. It is not known if this is a side effect of 5-HTP or if there is a contaminate in some 5-HTP products, as of 2015. For this reason, caution should be exercised when taking 5-HTP products, notes WebMD.
Pregnant or breastfeeding women should not take 5-HTP products, as it is possibly unsafe. Research suggests that 5-HTP may cause some individuals with Down Syndrome to have seizures. People should not take 5-HTP products within two weeks of surgery, as it can cause an increase of serotonin in the brain, which can cause anxiety, shivering and heart problems, according to WebMD.