With hCG diet centers popping up all over the country, hCG diet drops appearing everywhere, and some natural health practitioners and integrative physicians even offering the hCG diet to their patients, many people want to know more about this latest diet craze. What kind of evidence is there that the hCG diet really works? Is hCG dangerous?

The hCG hormone and diet

Human chorionic gonadotropin (hCG) is a hormone that supports the normal development of an egg in a woman’s ovary and stimulates the release of the egg during ovulation. It is produced in large quantities during pregnancy and is used as a prescription drug to cause ovulation and to treat infertility in women, and to increase sperm count in men. It is also used in young boys when their testicles have not dropped down into the scrotum normally. 

In the 1950s, a British physician, Dr. ATW Simeons published a scientific paper on treating obesity using a strict, fat-free, 500-calorie diet coupled with the use of low doses of hCG for periods of three and half to six weeks.[1] Dr. Simeons reported that by following the hCG diet, subjects could lose a pound a day while avoiding excessive hunger as well as the unwanted loss of muscle and structural fat.

Research on the hCG diet

Despite the claims, though, there is no evidence supporting their validity. The hCG hormone does not mobilize stored fat, suppress hunger, or promote weight loss, says Laurence Cole, PhD, Professor of Obstetrics and Gynecology and of Biochemistry and Molecular Biology at the University of New Mexico.[2]

According to Dr. Cole, one of the world’s leading researchers on hCG, there are no receptors for the hCG hormone present in the digestive tract, the liver, or in adipose (fat) tissue.[2] The hormone would likely have to act in one or more of these body tissues for it to have any action on mobilizing fat or suppressing hunger.

Numerous studies in the 1980s and ‘90s, many of which used clean, double-blind, and carefully controlled data and are considered to be of high quality, confirmed that the hCG diet did not and could not work. Results from studies indicate that all the weight loss achieved on the hCG diet is the result of severe calorie restriction (500 to 800 calories per day).[3]

The two highest quality hCG diet studies

One of the highest quality studies on the hCG diet was a double-blind, controlled study of 202 subjects comparing hCG injections and caloric restriction (with a 500-calorie-per-day diet) with placebo and caloric restriction.[4] For six weeks, subjects injected 125 units of hCG or placebo for six days of each week and followed the diet. They then gradually increased calories over the next six weeks (the maintenance phase). Following that, they underwent another 6-week injection phase, but this time those who had previously received hCG received placebo, and vice versa. Results showed that all the subjects lost the same amount of weight and the same percentage of body fat, whether injecting placebo or hCG.

The other high quality hCG diet study consisted of 51 women and compared 125 units of injectable hCG plus a 500-calorie diet with placebo plus a 500-calorie diet for 32 days.[5] All subjects were weighed daily and reported their degree of hunger on a five-point scale from no appetite to severe hunger. Also, all subjects had their hip and waist circumference measured on a weekly basis. Overall, the average total weight loss was the same in both groups, as was the average change in hip and waist circumference. No statistically significant difference was found in the hunger responses between the two groups.

Is hCG dangerous?

No significant safety studies with the hCG diet have been conducted. The risks to women who use hCG for dieting include cessation of menstruation and infertility, according to Dr. Cole.[2] Recently, physicians have published reports of subjects on the hCG diet suffering from manic episodes as well as life-threatening deep vein thrombosis and pulmonary embolism.[6,7] While there is no way to prove that hCG caused these conditions, in each case, it seemed likely that hCG was to blame.

When used at higher doses for medical purposes such as infertility, documented hCG side effects include[8]:

• bloating
• pelvic pain
• stomach pain
• decreased amount of urine
• feeling of indigestion
• nausea, vomiting, or diarrhea
• shortness of breath
• swelling of feet or lower legs
• weight gain
• difficult or labored breathing
• tightness in chest
• wheezing
• flushing of skin
• itching of skin
• redness of skin
• hives or welts
• enlargement of breasts
• vision changes
• severe, sudden headache
• slurred speech
• sudden loss of coordination
• sudden, severe weakness or numbness in arm or leg
• feeling sad or empty
• headache
• irritability
• loss of interest or pleasure
• trouble concentrating
• trouble sleeping
• tiredness