They were doing trials with this stuff for weight loss back in the 1970's, and studies showed that it has little to no effect on weight loss.

Also, since HCG is a natural hormone in your body, it can have many unexpected and detrimental effects. Hormone replacement therapy (estrogen) was big for a while until it was discovered to increase the risk of breast cancer.

I wouldn't risk your health or money on something that screams so loudly of scam.

HCG is an acronym for the hormone Human Chorio Gonadotropin, which is
found in both men and women, though pregnant women have the highest
levels of HCG in their bodies.
The HCG hormone can be made synthetically or extracted from a
pregnant woman's urine and then processed for use by other humans.
Advocates of the HCG diet believe that, by strict dieting
and taking daily injections of HCG, people can successfully lose
weight. They say that dieters following the HCG
diet should expect to lose somewhere between a half pound and 3 pounds
(.23 to 1.36 kilograms) each day on the low-calorie, high-fiber plan.
You consume a mere 500 calories a day on this diet.
They say that that combining the
low-calorie diet with the HCG hormone injections will lead to
immediate weight loss without the common side effects of many
diets, such as hunger pains, headaches and nausea. They
believe that because the HCG injections burn fat, the hormone provides
the body with necessary energy while reducing hunger and keeping the
body out of starvation mode.
Anybody eating that little is bound to lose weight, of course, and
many people found out that injection did not make it easier to bear
hunger.
And the drug lacks substantial research, so exposing your body to such
a restrictive diet may not be in your best interests.
The original HCG diet plan is quite restrictive and particular. For
breakfast, you can have only tea or coffee without sugar. The diet
puts a one-tablespoon limit on how much milk you can consume each day,
so if you require milk with your coffee and tea, you'll want to keep
this in mind. For lunch and dinner, you can cook 100 grams (.22
pounds) of lean meat or seafood and pair it with one vegetable from
this list of 13: asparagus, beet greens, cabbage, celery, chard,
chicory, cucumbers, fennel, green salad, onions, red radishes, spinach
and tomatoes. For lunch and dinner, you can eat one toast cracker and
an orange, apple, half a grapefruit or strawberries.
Administration of the hormone is usually through two methods — either an oral
supplement or a liquid injection.
The FDA has approved HCG injections for use in fertility issues, but not in dieting.
There are a few dangers that come with injecting HCG into your body.
As with any injected medication, the potential for blood clots exists. Some women
who have injected HCG have experienced a serious condition called
ovarian hyperstimulation syndrome (OHSS), which can be deadly.
Other less serious side effects might be headaches and
depression. Young boys taking HCG might experience premature puberty.
Pregnant or nursing women could cause harm to their
babies if the hormone is passed on.
And although advocates claim that HCG keeps the body functioning
properly, a diet of 500 calories is below any healthy amount
recommended by most doctors. Weight loss is almost guaranteed when
you're eating so much less than the recommended daily allowance, but
you may risk your health. And although the HCG is supposed to help
with side effects, in one study the HCG injections showed no different
feelings or results than a placebo injection.