HCG is a hormone that is naturally produced by humans. It is also used, in far larger doses than when it is taken for weight loss, as a medical treatment, typically for fertility problems. HCG has been associated with certain side-effects when it is given as a fertility treatment. Although it is less likely that these side-effects will be experienced when taking the lower doses that are used as part of the HCG diet, it is still possible for some dieters to suffer from side-effects.

The most common side-effect that has been linked with HCG is headaches. Other side-effects that may be experienced by people who are taking HCG include feelings of irritability or restlessness, tenderness or swelling of the breasts, bloating, and, if the HCG is being injected, inflammation and pain at the injection site.

A few more serious side-effects have also been linked with taking HCG. HCG can stimulate the early onset of puberty if it is taken by young boys. In women, it can cause a condition called ovarian hyper-stimulation syndrome, which can be very serious and which may even be fatal if it is not treated. The symptoms of OHSS are swelling in the hands or the legs, abdominal swelling, stomach pain, nausea, vomiting, weight gain, diarrhea, pelvic pain and infrequent urination.

It is sensible to consult a doctor before starting the HCG diet since they will be able to provide advice about whether or not it will be suitable. Should any side-effects be experienced during the diet, it is important to discuss them with a physician.
HCG should never be taken during pregnancy or by a woman who is nursing. People who are suffering from any medical conditions or who are taking any type of medication should consult their doctor before taking HCG in order to ensure that there will be no additional risks or drug interaction problems.