Is the HCG Diet Safe? How it Damages your Thyroid & Metabolism

Is the HCG Diet Safe? How it Damages your Thyroid & Metabolism

Are you thinking about doing the HCG diet for weight loss?

If so you are probably wondering…

Is the HCG Diet safe?

Will it harm my metabolism?

Will it cause thyroid damage or make my thyroid function worse?

​And you are right to ask these questions before you undergo the treatment!

The truth is that the HCG diet can cause damage to both your metabolism and your thyroid function and I will explain it in this post.

As a physician, I’ve had the advantage of treating patients before, during, and after undergoing the HCG diet.

​I know that so many of you out there are desperate to lose weight and you’ll basically do anything to get there, but let me tell you this:

There is a better way to lose weight and it has nothing to do with the HCG diet. I will explain more about this in this article as well.

Let’s dive in…​

Why You Shouldn’t do the HCG Diet if you want to Lose Weight

The problem with weight loss is that we are using a flawed model.

Our current paradigm says that in order to lose weight you must decrease the number of calories you consume and exercise more.

Doing this will allow your body to enter a state of energy balance which will result in calories and fat being burned in the process.

This all sounds well and good, the problem is that it just doesn’t work.

If you don’t believe me then just take a look at the success rate of calorie-restricted diets (of which the HCG diet is most certainly a part).

The data show that approximately 98% of people fail to maintain long-term weight loss on diets such as these.

So that means 1 of two things:

1. We either need to eat even less or exercise even more…

2. Or, just maybe we really don’t understand the real reason why we both gain and lose weight

​I tend to focus on the latter. 

In this model weight gain is primarily driven by hormonal abnormalities, NOT excessive consumption of calories.

Now, this doesn’t mean that food isn’t important.

On the contrary.

You see food and calories are considered information and they directly have an impact on your hormones themselves.

So let’s say you eat lots of refined carbohydrates, sugars, pasta, and pastries and you gain 20+ pounds.

Our current paradigm would suggest that this gain was due primarily to the increased amount of calories you consumed.

And while that is certainly part of the problem, it doesn’t explain everything.

In reality, the excess calories contributed to high insulin levels which sent the signal to your body to store excess energy as fat. 

​This hormonal dysregulation causes weight gain and hormone imbalances that directly lead to weight gain. 

So how does this apply to the HCG Diet?

Well, the problem is that simply reducing calories may temporarily result in weight loss, but it does nothing to fix the hormone imbalance.

So what happens?

You get hit with a double whammy:

Not only do you gain ALL the weight back you lost (because you didn’t treat the primary problem).

You have now also caused some further hormone imbalances (metabolic and thyroid damage) in the process.

​The bottom line?

If you are considering the HCG Diet you need to take a step back and read through the rest of this article so you have a better idea of WHY you are actually overweight in order to understand how to treat it. ​


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The HCG Diet vs HCG The Hormone

​Before we talk about how the HCG diet can damage several hormones in your body we need to distinguish between the HCG diet and HCG the hormone. 

The HCG Diet is a calorie-restricted diet (to various levels) plain and simple. During the calorie restriction, patients use the hormone HCG to help boost weight loss in “hard-to-reach” places.

​Now compare that to the hormone:

The hormone HCG (which stands for human chorionic gonadotropin (1)) is secreted by pregnant women. 

​Now here is where things get interesting and why we need to differentiate between the two:

The ​HCG Diet is a calorie-restricted diet that will cause metabolic and hormone damage. 

Much of the bad name that the HCG Diet brings is wrongly associated with the hormone and it isn’t really fair.


Because HCG by itself is actually quite helpful.

Studies have shown that HCG the hormone, can actually help stimulate thyroid function (2) and actually increase thyroid hormone release (3). 

So now we are in kind of a pickle.

I just said that the HCG diet harms your thyroid, but that the HCG hormone itself actually can increase thyroid function.

This may explain why SOME (a small minority of patients) can actually go through the HCG diet without suffering major metabolic and thyroid damage.

This also probably explains why anyone with some baseline thyroid disorder that goes through the HCG Diet is left devastated.

​The point is this:

The HCG hormone itself has some uses as long as it is not paired with a chronic calorie-restricted diet.

In fact, I’ve used HCG by itself (without the diet portion) to help patients lose weight by boosting thyroid function and improving estrogen/progesterone levels. 

HCG can also be used safely to help improve fertility in both men and women (4) and it is an important part of male testosterone replacement therapy (to prevent testicular atrophy).  

The HCG Diet and Your Thyroid

​So now you may be asking:

What will happen to my thyroid if I undergo the HCG Diet?

First, you need to understand what the thyroid does and why it is so important. 

Your thyroid controls your metabolism and the amount of energy that you consume and burn at rest.

This is sometimes referred to as the resting energy expenditure (5) or the resting metabolic rate.

text which outlines the wikipedia definition of resting energy expenditure.

​The resting energy expenditure is the single most important factor for determining if you will lose weight and if you will keep it off. 

This amount of energy consumed represents the MAJORITY of calories burned throughout the entire day.

And no – you can’t sit on a treadmill and seriously burn 1,000 calories, your body doesn’t work that way (if it did none of us would be overweight). 

So the amount of energy you burn on a daily basis just thinking, breathing and living is what really determines how and if you will lose weight.

And what you need to understand is that the HCG Diet actually REDUCES this number and this is how it damages both your thyroid function and your metabolism. ​

As little as 21 days of consistent calorie restriction is enough to reduce your metabolism by up to 40%. You can find the studies here (6). 

a study with text highlighted which describes the relationship between energy intake, exercise, and their effect on resting metabolic rate.

What’s crazy is that we have known this since the ’90s.

Calorie restriction reduces your energy expenditure and your resting metabolism is what is responsible for the majority of weight loss maintenance.

So in a way you are basically shooting yourself in the foot when you reduce your calories hoping to lose weight.

You will lose some weight initially, but you will damage your metabolism in the process and then the weight will come right back on once you start eating normally.

​Now imagine doing this over and over again, each time your metabolism slows just a little bit. 

You went from burning 2,000 calories at rest to 1,800 after your first diet, then 1,600 after your second diet, then 1,400, etc., etc.

Now you are burning 1,000 calories at rest and the only way to even maintain your current weight is to eat that amount of calories.

Does this sound familiar?

This isn’t in your head, and you can actually measure the number of calories you burn at rest with a device known as indirect calorimetry.

Unfortunately just knowing your metabolism is damaged doesn’t tell you how to fix it, but we will touch on that later. 

HCG Side Effects

So what kind of OTHER side effects should you expect after undergoing the HCG Diet?

​We mentioned a couple above and we will go into detail on the others below. 

Negative side effects of the HCG Diet: ​

  • Damaged metabolism and metabolic function
  • Lower resting metabolic rate or resting energy expenditure
  • Damaged thyroid function with high reverse T3 and low free T3
  • Reduced progesterone levels lead to estrogen dominance
  • Reduced basal body temperature
  • Cold hands/extremities
  • Hair loss
  • Weight gain
  • Depression, anxiety, or other mood-related changes

​As you may have noticed many of these side effects mimic symptoms of hypothyroidism (you can see the full list in this post). 

​And that is definitely true. 

Metabolic damage and low thyroid tend to go hand in hand and share many of the same symptoms.

In addition, calorie restriction of any kind will lead to some very characteristic symptoms like changes in skin texture, hair loss, etc.

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These occur as your body attempts to conserve energy for the more vital functions in the body and ​takes energy away from things that are less important or considered “cosmetic”. 

Now it’s important to realize that many of these symptoms are caused by the calorie restriction component NOT the HCG hormone itself.

They tend to get lumped together because both the Diet and the hormone are used together, but in reality, the side effects are quite different. 

As an aside, if you are using sublingual HCG drops all of your symptoms are due to calorie restriction and starvation NOT the hormone. 

The reason is that the sublingual HCG drops don’t actually get absorbed, so in effect, they are more like a placebo than anything else. 

​Below I’ve included some symptoms of the HCG hormone itself. 

Side effects of the HCG hormone shot:

  • Mood changes like anxiety or depression
  • Feelings of irritability or restlessness
  • Swelling of the extremities (typically lower legs and ankles)
  • Headaches or migraines (although symptoms HCG will get rid of these symptoms as well)
  • Other symptoms that mimic PMS or PMDD

​Now you might notice that many of these symptoms mimic symptoms you may experience with or around your cycle. 

And you would be correct because of how HCG works in the body.

In females, it can actually help stimulate ovulation and thus it may alter estrogen/progesterone levels leading to many of the symptoms above.

​This is why it can also be used to help reverse some of these problems and to improve fertility in certain patients. 

The HCG Diet, Thyroid Function, and Reverse T3

So what if you’ve already done the HCG diet once, twice, or even three times? What if you are experiencing many of the symptoms I mentioned above?

​The good news is that many of these symptoms can be treated. 

The damage from the HCG Diet hits the thyroid particularly hard, but it can be reversed and treated – but you have to know what you are looking for.

I’ve had the advantage of treating patients immediately after the HCG diet, during the HCG diet and I’ve seen the long-term effects of multiple rounds of the HCG diet as it relates to thyroid function.

Typically after the HCG diet, patients may have some or all of the following thyroid lab changes:

Below is an example of a patient who just recently underwent the HCG diet (30+ days in a row)…

lab tests results from a hypothyroid patient with an abnormal reverse T3 level highlighted.
lab test results from a thyroid patient showing a low normal sex hormone binding globulin.

You can see from this example the reverse T3 is very high at 41.1 and the sex hormone-binding globulin is low at 25. 

This means that the cells and tissues aren’t getting enough thyroid hormone. Period. 

You can read more about how to interpret thyroid lab results in this post

​If you have labs similar to the ones above AND you have symptoms of hypothyroidism then there is a VERY high chance you are suffering from thyroid damage. 

How to Actually Lose Weight

This is all well and good, but knowing this how do you actually go about losing weight?

The truth is that you have to make sure you are attacking the RIGHT problem.

The majority of weight gain and weight loss resistance is from hormone imbalances.

In most patients, especially if they’ve done any calorie-restricted diet in their life (most of you have!) then you are most likely suffering from thyroid resistance to some degree.

In addition, as many as 50% of you (based on statistics) also have insulin resistance.

The combination of these two hormone imbalances causes most of the weight gain you may be experiencing. 

I’ve compiled step-by-step case studies that you can go over below. All of the patients have some degree of hypothyroidism as well as weight loss resistance:

​Use these case studies to help you understand HOW to lose weight and notice how each patient has their own set of hormone abnormalities leading to weight loss resistance. 

What you need to remember is that each of you is quite different – which means that no two treatment plans will be the same.

What to do if you’ve Already Done the HCG Diet Multiple Times

If you’ve already done the HCG diet and you’ve been reading through this article then you fall into a special situation. 

Unfortunately, most patients don’t get to me until they’ve done considerable damage to both their thyroid and their metabolism, and the longer you go untreated the more difficult it is to reverse the problem.

But that is the point:

These problems CAN be reversed.

I’ve actually been able to treat people during the HCG diet and by giving them pure T3 I’ve been able to reduce many of the symptoms and prevent the majority of weight gain that many patients experience.

The single best thing you can do is to find a practitioner that is both willing to work with you and understands how hormones function in the body.

You don’t necessarily have to use pure T3 but some combination of medications that contains T3 may be necessary depending on how high your reverse T3 levels are. ​

In addition, you will most likely need to be tested for leptin resistance and treated if present as well. 

The next (and more difficult part) comes in treating your metabolism.

You can find helpful hints and tips on how to do this here.

The most important part?

STOP doing the diet and STOP calorie-restricting your body!

That will go a long way to fixing the problem. ​

Wrapping it up

The bottom line:

The HCG Diet can harm your metabolism and your thyroid function, ultimately leading to weight gain once you stop the diet.

The bigger problem is that the damage to your thyroid and metabolism is long-term (at least up to 6 years based on the biggest loser study (7)) and can be difficult to reverse.

If you are thinking about undergoing the HCG diet please read the risks carefully before you proceed.

I would also recommend a full hormone panel to determine WHY your body is actually gaining weight and then treating and reversing those problems. ​

Now it’s your turn:

Is your metabolism damaged after the HCG Diet?

Is your reverse T3 elevated as a result of calorie-restricted dieting?

Did the HCG Diet work for you? Why or why not?

Leave a comment below!​








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About Dr. Westin Childs

Hey! I'm Westin Childs D.O. (former Osteopathic Physician). I don't practice medicine anymore and instead specialize in helping people like YOU who have thyroid problems, hormone imbalances, and weight loss resistance. I love to write and share what I've learned over the years. I also happen to formulate the best supplements on the market (well, at least in my opinion!) and I'm proud to say that over 80,000+ people have used them over the last 7 years. You can read more about my own personal health journey and why I am so passionate about what I do.

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