Can HCG for Weight Loss Hurt Your Thyroid?

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Weight loss options are numerous for people who want to slim down and keep their weight in a healthy range.

While excess weight can be stubborn, a good strategy is all that it takes to slim down and decrease the risk of many health conditions.

It’s not uncommon for people to try with HCG; you’ve probably heard about it or thought of doing the same to lose weight.

But what are the consequences of HCG, and is it harmful to the thyroid gland?

What is HCG?

Although HCG is a widely used term, most people are not quite sure what it represents. Before we can even begin discussing HCG for weight loss and its potential impact on the thyroid it’s useful to address it first.

HCG stands for human chorionic gonadotropin, and it is a hormone produced mainly during the pregnancy. The primary function of HCG is to stimulate the corpus luteum to secrete progesterone in order to maintain pregnancy. Corpus luteum is a temporary structure or a mass of cells formed in an ovary to produce progesterone during the pregnancy.

Certain amounts of HCG are also produced in other parts of the body, such as the liver, pituitary gland, and the colon[i].

Why is HCG popular today?

Chances are you have probably seen HCG everywhere today. People talk about their experiences online, there are tons of articles that instruct people how to take and inject HCG, and whatnot.

This trend shows no signs of slowing down, and it is impossible not to wonder why. Generally speaking, HCG is used to treat fertility problems and help the couples conceive.

But people across the globe have started using HCG for purposes that are not its initial function. Weight loss is one of them.

HCG for fertility problems is available with a prescription only. That is the only use of HCG approved by the FDA. It’s useful to bear in mind that HCG is also not approved for the over-the-counter use, and FDA emphasizes it is not for weight loss[ii]. However, HCG in the form of dietary supplements is widely available, and people across the globe use it to slim down.

What is the HCG diet?

The whole idea of HCG for weight loss originated in 1954 when Albert Simeons, a British doctor, suggested the HCG diet could help people slim down. Today, the HCG diet is widely popular, and it consists of two main parts: ultra-low calorie intake of 500 calories a day and injecting HCG or taking it in other forms.

The reason why HCG is considered beneficial for weight loss is that it’s a protein-based hormone which can speed up the metabolism and allow people to lose weight and retain their muscle mass. Advocates of the HCG diet claim they lose fat, but not muscles.

Current evidence on this subject does not support the claims that the HCG diet can cause significant weight loss because of the hormone itself. People lose weight due to significant calorie restriction and not because of HCG[iii],[iv], studies show.

People who want to try the HCG diet need to adhere to three phases.

First is the loading phase, where it is necessary to start taking HCG and consume high-calorie and high-fat foods for two days.

Second is the weight loss phase characterized by using HCG and lowering calorie intake to 500 calories a day for three to six weeks. This accounts for two meals a day.

Next is the maintenance phase, where a person stops taking HCG and increases food consumption gradually. But this doesn’t mean it’s okay to eat everything and anything; people still need to avoid starch and sugar for three weeks.

Can HCG affect the thyroid?

HCG has become a hot topic later as an increasing number of people use it for one reason to another. But when we are talking about HCG for weight loss, it’s also important to discuss whether it could have an unfavorable impact on the thyroid gland.

Not many studies have been conducted on this subject, and hopefully, we can expect that to change in the near future. The ever-growing popularity of HCG should call for further research on an array of subjects.

Hyperthyroidism risk

Korevaar et al. conducted a study whose main objective was to determine whether HCG could be a risk factor for some thyroid disease. For the purpose of the study, scientists measured HCG and thyroid hormone levels in 5435 pregnant women.

Results, published in the journal thyroid, showed that higher HCG levels were associated with an elevated risk of subclinical and overt hypothyroidism. This particular study found that HCG levels weren’t linked with subclinical hypothyroidism[v].

HCG diet vs. HCG hormone

When we are talking about the impact of HCG on weight loss on the thyroid gland, it is important to distinguish the line between the HCG diet and HCG hormone on its own. HCG diet, as previously mentioned, is indicated by significant calorie restriction and could be bad for our health in more ways than one.

On the other hand, the hormone on its own can be quite helpful, actually. Evidence shows that the HCG hormone has the ability to stimulate thyroid function[vi] and it can increase the release of thyroid hormone[vii]. These particular benefits of HCG may explain why some patients can go through the HCG diet without suffering damage or any kind of dysfunction to their thyroid gland.

How can the HCG diet affect the thyroid gland?

As seen above, HCG itself can be beneficial for the thyroid gland. But if HCG is a major component of the HCG diet, then what makes it so bad in this scenario?

The truth is, the negative impact on the thyroid gland here is mainly due to severe calorie restriction and not the hormone itself.

The thyroid gland has many roles in the body, including the regulation of metabolism and the amount of energy we eat or burn at rest i.e., resting energy expenditure or metabolic rate. The resting energy metabolic rate is the most important factor that determines whether we will lose weight and manage to keep it off.

Now let’s go back to the HCG diet; it decreases the resting energy metabolic rate and thereby slows down the metabolism and thyroid function. In order to slim down, you need to speed up the metabolic rate. Low thyroid function leaves us with an insufficient amount of thyroid hormones that our body requires to work properly.

HCG diet may also have various adverse reactions such as:

  • Hair loss
  • Cold hands and feet
  • Weight gain
  • Depression, anxiety, and other mood changes
  • Decreased basal body temperature
  • Damaged thyroid function (high rT3 and low free T3)

Take a look at the symptoms above. Do they remind you of anything?

Hypothyroidism can also lead to weight gain, hair loss, cold hands, depression, and other symptoms. The similarity is not a coincidence in this case. Low thyroid function and metabolic damage go hand in hand. Remember, thyroid regulates metabolism!

Do all people have thyroid damage due to HCG or HCG diet?

The use of HCG and HCG diet has become a major trend over the years, so you’re probably worried about your thyroid gland.

Above in the article, it was mentioned that the adherence to the HCG diet could induce HCG damage not due to the hormone itself but as a result of severe calorie restriction. That being said, it is important to point out that all people are different and their body reacts to HCG and HCG diet in a different manner.

Some people may not have thyroid damage on this diet. For example, one blogger reported that the HCG diet helped lower the dose of thyroid medications she had to take for Hashimoto’s thyroiditis.

She was taking 87.5mcg of T3, Cytomel before she started with the HCG diet. Cytomel is a powerful medication, and 87.5mcg is a pretty high dosage. After the HCG diet, her daily dose of Cytomel was reduced to 12.5mcg. As of June 2014, she has been off all medication.

This seems promising, but you should also bear in mind the blogger does not specifically know what helped reduce the drug dosage i.e., whether it was an HCG diet or something else.

Is it possible to reverse thyroid damage caused by HCG?

At this point, you’re probably wondering what happens when thyroid damage occurs due to the HCG diet. Is it possible to reverse it?

If you have used HCG or adhered to the HCG diet, it would be practical to see your healthcare provider and consult about thyroid health. Your doctor may order blood tests to inspect the levels of thyroid hormones.

If the damage has, indeed, occurred, the doctor will probably advise you to stop taking HCG/following the HCG diet. That is the first step! It is entirely possible to reverse the damage, but you need patience, strong willpower, and healthy lifestyle choices.

The complete management of this problem depends on the severity of the damage. For example, the doctor may order tests to analyze other hormone levels in order to propose necessary measures to speed up metabolism. You may need to consume a well-balanced diet and avoid restricting your calories severely.

In cases with severe damage, patients may need to take thyroid hormone replacement, but this isn’t a rule. In other words, if your thyroid damage is not serious, you won’t have to use medications. Lifestyle modifications could be enough.

HCG products

HCG injections are available with doctor’s prescriptions only, but nowadays, there are many HCG products available as supplements and thereby sold in the over-the-counter form. Caution is needed before the purchase.

Many products are presented as natural and effective solutions, but the market of dietary supplements is not strictly regulated, and things aren’t always as they seem. Do a little research before you buy, avoid scam-like brands and products, go through customer reviews, and make sure you opt for a product made by a reputable brand.

Healthy weight loss

Weight management is important for good health and wellbeing, particularly if you also have some thyroid problems. Conditions affecting the butterfly-shaped gland can cause weight fluctuations, so you may feel inclined to try out different solutions to keep it under control. Healthy weight management is entirely possible and only requires a few lifestyle adjustments, such as:

  • Don’t starve yourself and skip meals
  • Eat-in moderation
  • Prioritize a well-balanced diet rich in fruits and vegetables, nuts and seeds, and other nutrient-rich items
  • Reduce intake or entirely avoid heavily processed and refined foods
  • Quit smoking
  • Be proactive about thyroid condition management
  • Exercise regularly and increase activity levels
  • Meditate or find some other stress management strategy
  • Get enough sleep
  • Stay hydrated throughout the day, but opt for water rather than sugar-laden store-bought fruit juices


HCG has become a frequently mentioned term lately as millions of people around the globe use it to lose weight or for some other purposes besides the initial fertility treatment role.

HCG is also used as a part of the HCG diet for weight loss. The influence of this hormone on thyroid can be quite complex. While HCG on its own may help weight loss, the diet can damage thyroid and induce symptoms of hypothyroidism.

Before you start using HCG or following the HCG diet, make sure to consult the healthcare provider about all their advantages and disadvantages.


[i] Betz D, Fane K. (2019). Human chorionic gonadotropin (HCG). StatPearls. Retrieved from:

[ii] Zeratsky K. Has the HCG diet been shown to be safe and effective? Mayo Clinic. Retrieved from:

[iii] Bosch B, Venter I, Stewart RI, Bertram SR. (1990). Human chorionic gonadotropin and weight loss. A double-blind, placebo-controlled trial. South African Medical Journal, 77(4):185-9. Retrieved from:

[iv] Stein MR, Julis RE, Peck CC, et al. (1976). Ineffectiveness of human chorionic gonadotropin in weight reduction: a double-blind study. American Journal of Clinical Nutrition, 29(9):940-8. Doi: 10.1093/ajcn/29.9.940. Retrieved from:

[v] Korevaar TI, de Rijke YB, Chaker L, et al. (2017). Stimulation of thyroid function by human chorionic gonadotropin during pregnancy: a risk factor for thyroid disease and a mechanism for known risk factors. Thyroid, 27(3):440-450. Doi: 10.1089/thy.2016.0527. Retrieved from:

[vi] Kennedy RL, Darne J. (1991). The role of HCG in the regulation of the thyroid gland in a normal and abnormal pregnancy. Obstetrics and Gynecology, 78(2):298-307. Retrieved from:

[vii] Kraiem Z, Sadeh O, Blithe DL, Nisula BC. (1994). Human chorionic gonadotropin stimulates thyroid hormone secretion, iodide uptake, organification, and adenosine 3′,5′-monophosphate formation in cultured human thyrocytes. Journal of Clinical Endocrinology and Metabolism, 79(2):595-9. Doi: 10.1210/jcem.79.2.8045981. Retrieved from:

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