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HCG Diet: What It Is, What the Evidence Shows, the Risks

Quick answer. The HCG diet combines HCG products with a very low-calorie eating plan, often 500 to 800 calories a day. The FDA has not approved HCG for weight loss and says any weight lost comes from the severe calorie restriction, not from HCG. Clinical trials have not shown that HCG helps, and Mayo Clinic says the diet isn't safe.

By USAHCG · Updated November 15, 2026. Educational information; discuss individual decisions with your clinician.

What is the HCG diet?

It pairs injections, drops or pills containing HCG with a very restricted diet. A physician, A.T. Simeons, described the approach in medical papers in the 1960s. Mayo Clinic says it most often means taking in 500 to 800 calories a day (Mayo Clinic). HCG itself is a hormone made during pregnancy. It is a prescription medicine for other conditions; see our HCG injections guide.

Does the HCG diet work?

The best evidence says no. A 1995 review pooled 8 controlled and 16 uncontrolled trials. Most studies were of poor quality, and among the 12 stronger ones only one reported that HCG helped. The authors concluded there is no scientific evidence that HCG works for obesity: it doesn't cause weight loss or fat redistribution, and doesn't reduce hunger (Lijesen et al., 1995).

Earlier double-blind trials found the same. A 32-day trial of 51 women found HCG ineffective for weight reduction (Stein et al., 1976), and a crossover study of 202 patients found no significant difference between HCG and placebo (Young et al., 1976).

What do the FDA and Mayo Clinic say?

The FDA approved HCG as a prescription drug for female infertility and other medical conditions, and not for weight loss. An FDA official says: "any loss is from severe calorie restriction. Not from the HCG." The prescription label states there is "no substantial evidence" that HCG increases weight loss beyond what calorie restriction produces (FDA).

Mayo Clinic says the HCG diet isn't safe and doesn't lead to long-term weight loss.

Why do people lose weight on it?

Eating very few calories causes weight loss in the short term, whatever else you take. Mayo Clinic says people on such diets are likely to lose weight in the short term, but the diets carry risks and don't lead to lasting loss.

HCG drops and sprays

Over-the-counter HCG drops and sprays sold for weight loss are not FDA-approved. The FDA and FTC have sent warning letters to companies marketing them, and the FDA advises consumers to avoid HCG weight-loss products (FDA).

Risks and side effects

Very low-calorie diets can cause:

  • Gallstones.
  • Irregular heartbeat.
  • Low vitamins and minerals.
  • Electrolyte levels that are too high or too low.

Mayo Clinic also lists common side effects of the HCG diet: depression, extreme tiredness, swelling from trapped fluid, headache, trouble sleeping, and breast enlargement in men. Rare effects include blood clots, testicle tumors and ovarian cysts. It adds that HCG weight-loss products are linked with making some cancers worse, including prostate cancer.

What to do instead

  • Talk to a clinician first. They can check your health and tell you whether any very low-calorie diet is safe for you.
  • Reduce calories gradually. The FDA's advice is to lose weight gradually by reducing the calories you eat each day.
  • Ask about medicines that passed proper trials. For example, in the two-year STEP 5 trial of 304 adults, average weight change was -15.2% on semaglutide vs -2.6% on placebo, both with lifestyle support (Garvey et al.). That is a prescription decision for you and your clinician. See Semaglutide vs Ozempic.

We don't publish menus, phase plans or calorie schedules for the HCG diet. Our guides on snacks and melba toast cover everyday food choices and how to read labels, not a protocol.

Frequently asked questions

Does the HCG diet work?

Trials haven't shown that HCG helps. Weight lost comes from the very low calories.

Is HCG approved for weight loss?

No. The FDA has approved it only for other conditions.

How many calories is the HCG diet?

Mayo Clinic says most often 500 to 800 a day. The FDA says usually about 500.

Are HCG drops effective?

The FDA says HCG weight-loss products aren't approved and has sent warning letters to sellers of them.

How much do HCG injections cost?

The current price of a USAHCG 5,000 IU vial is on the product page. HCG is a prescription drug in the U.S.

What's better, Clomid or HCG?

They are different medicines for fertility problems, so that is a question for a fertility specialist, not a diet question.

Is the HCG diet safe?

Mayo Clinic says it isn't safe.