Why Your Metabolism Is Slow Even Though Your Blood Test Is Fine

Ever feel like your metabolism is slow, but the doctors test revealed everything is fine?

Well, it’s likely not fine.

And this short article is going to breakdown exactly why you may still be feeling sluggish with poor energy or are struggling to lose weight, even though your thyroid labs are ‘normal’.

If you head to your doctor in the UK and complain of difficulty losing weight, one of the first things they will do is ‘test your thyroid’. This means they’re going to look at some of the hormones which regulate energy production in your body.

In this case, they run markers to check 2 of your thyroid hormones.

TSH and T4. 

TSH or Thyroid Stimulating Hormone produced in the pituitary gland stimulates your thyroid to produce the hormone T4.

T4 which is the inactive form of your thyroid hormone is also measured.

But here’s where the fun begins.

There is a nice range in which both of these are deemed acceptable by your doctor. 

In the standard western approach to care…

Outside of the range = problem.

Inside the range = You’re fine come back another day.

But the problem is this; the range is quite…. large. 

Here is an example.

TSH Range is from 0.4 to 4 mU/L (milliunits per litre)

The biggest problem is that if you’re trending high, or trending low, there is no guideline for medication. It means you don’t yet have a disease. 

So you are not deemed necessary of any intervention.

The problem is, trending high or trending low is allowing you to predict the future, if you know what you’re looking for.

But as with all hormones, none of these values work alone, so lets look at the other markers.

The inactive form (this becomes apparent soon) of the thyroid hormone which is T4 or thyroxine.

The range for thyroxine is also quite broad…

Free T4 Levels are from 
9 to 25 pmol/L (picomoles per litre)

So even if your TSH or T4 is extremely high or low, but within range, you will not get any medication.

Medication normally prescribed for people with low thyroid levels is Levothyroxine.

From the NHS website, 

Treatment for an underactive thyroid involves taking daily hormone replacement tablets, called levothyroxine, to raise your thyroxine levels. You’ll usually need treatment for the rest of your life

Essentially you are given the synthetic hormone version of Thyroxine (T4).

But here’s where it starts to get crazy.

T4 is the INACTIVE form of your thyroid hormone. It is not the active form needed to raise your metabolism. 

That active form is called T3.

And in order to convert T4 into the active and usable form of T3, you need to convert that hormone

And this is where most peoples problems lie. 

The enzymes that do the conversion are called deiodinases, and in order for your body to do the proper conversion you need the following.

  1. Enough of the minerals which these enzymes use (For example, adequate levels of Selenium is essential)
  2. Low stress levels (because they block the conversion)
  3. A healthy liver and gut (because this is where most of the conversion is done)

So your doctor can prescribe as much T4 as they like, but if you’re not converting it into T3 then absolutely nothing will happen for you.

Also, on each cell you have thyroid receptors and damage to these receptors by eating the wrong type of fats will also stop this conversion.

In fact, you’ll likely need to go back to your doctor to get an increased dose of T4. 

So what’s the fix?

Everything is unique and without testing, it is impossible to see where in these phases of conversion you are lacking.

First you need proper testing.

TSH and T4 are just 2 of many markers you will need to be checked, by your endocrinologist or health care practitioner. 

You will also need to check

Free T3


Thyroid antibodies (for autoimmune conditions)

Once you have all those labs you can see where the breakdown is occurring.

Next you move on to testing what is breaking those steps and it could be as simple as a hidden iodine deficiency.

Stress is the biggest cause of blocking thyroid hormone conversion in my experience, so I normally start there with my clients, and work to fix their nutrient issues (with testing of course).

If you are experiencing low energy, poor mood and incredibly slow weight loss then make sure you work with the right healthcare practitioner in getting to the root cause of your problem.

Or as the NHS website states, “You’ll usually need treatment for the rest of your life

To find out more about testing contact us at the RMF Gym here


Disclaimer: This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read in this article. It is for information purposes only.