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Reverse T3 test for people with persistent fatigue and metabolism issues

Blood Test for Persistent Fatigue and Slow Metabolism

Reverse T3, LC/MS/MS

Google
3,138 reviews
  • Pinpoint the cause of your fatigue
  • Reveal hidden thyroid imbalances effortlessly
  • Clarify why your metabolism feels off
First results as soon as overnight*

90 day happiness guarantee

We stand behind our service

Prescription & fees included

Go directly to the lab, no extra fees

Easy to understand results

With friendly doctor's notes & guidance

Fast & convenient

Lab visit as quick as 10 mins in & out

90 day happiness guarantee

We stand behind our service

Prescription & fees included

Go directly to the lab, no extra fees

Easy to understand results

With friendly doctor's notes & guidance

Fast & convenient

Lab visit as quick as 10 mins in & out

What's this test for?

This test is ideal if you're experiencing persistent fatigue, unexplained weight gain, or feeling like your metabolism has slowed down despite normal thyroid test results. It measures Reverse T3, which can reveal hidden thyroid imbalances that standard thyroid tests might miss. Many people use this test when they have ongoing symptoms but their regular thyroid tests come back normal, or when dealing with chronic illness that affects how their body uses thyroid hormones.

How should I prepare for this test?

No special preparation is needed for this test. You don't need to fast before your blood draw, and you can take your medications as usual. Simply visit a lab location at your convenience to have your blood sample collected.

What's included in this test?

T3 Reverse, LC/MS/Ms

This test measures Reverse T3 (rT3), an inactive form of thyroid hormone that can block the effects of active thyroid hormone when levels are too high. Elevated Reverse T3 is common during chronic illness, severe stress, or calorie restriction, and can explain why you feel hypothyroid symptoms even when standard thyroid tests appear normal. This measurement helps identify thyroid hormone conversion issues that affect your metabolism and energy levels.

What happens after I get my results?
You'll receive detailed doctor notes in simple language explaining what your Reverse T3 levels mean for your energy, metabolism, and thyroid function. These notes include personalized recommendations like dietary adjustments, stress management techniques, supplement suggestions, or whether you should follow up with an endocrinologist. You'll also get the standard lab report and can track your Reverse T3 levels over time using our trends feature to monitor how your interventions are working.
Who should consider getting this test?
This test is particularly useful for people with persistent fatigue and metabolism issues despite normal TSH and thyroid hormone levels. It's also valuable for those dealing with chronic illness, recovering from severe stress or trauma, anyone following a very low-calorie diet, or people with symptoms of hypothyroidism whose standard thyroid tests don't explain their symptoms.
What symptoms indicate I may need this test?
Common signs include ongoing fatigue even after getting enough sleep, difficulty losing weight despite diet and exercise efforts, feeling mentally foggy or having trouble concentrating, and experiencing cold intolerance or low body temperature. Other symptoms include hair loss, dry skin, depression, or feeling like your metabolism has slowed down, especially if your regular thyroid tests have come back normal.
How can I naturally support healthy Reverse T3 levels?
Managing stress through meditation, yoga, or deep breathing exercises can help normalize Reverse T3 levels. Ensuring adequate selenium intake through foods like Brazil nuts, eggs, and fish supports healthy thyroid hormone conversion. Getting sufficient sleep, avoiding extreme calorie restriction, and treating any underlying chronic conditions or infections are also important. Regular moderate exercise and maintaining stable blood sugar levels can further support balanced thyroid function.
What is Reverse T3 and why does it matter?
Reverse T3 is an inactive form of thyroid hormone that your body produces as a way to slow down metabolism during times of stress, illness, or low calorie intake. When Reverse T3 levels get too high, it can block your active thyroid hormone from working properly, leading to symptoms like fatigue and weight gain even if your other thyroid tests look normal. It's essentially your body's brake pedal on metabolism, and understanding your levels helps explain why you might feel hypothyroid despite normal test results.
What does high Reverse T3 mean?
High Reverse T3 typically indicates that your body is converting too much of your thyroid hormone into the inactive form, which can happen during chronic stress, illness, severe dieting, or inflammation. This means less active thyroid hormone is available to your cells, which can cause symptoms like fatigue, weight gain, brain fog, and feeling cold. High Reverse T3 often explains why someone feels hypothyroid even when their TSH and T4 levels appear normal.
How often should I retest my Reverse T3 levels?
If you're making lifestyle changes or working with a healthcare provider to address elevated Reverse T3, retesting every 8-12 weeks allows you to track your progress. Once your levels normalize and symptoms improve, testing every 6-12 months helps ensure they remain stable. If you're dealing with ongoing chronic illness or high stress, your healthcare provider may recommend more frequent monitoring to adjust your treatment approach.
How’s this work?
Getting your blood test with us is easy, private & backed by the power of science.

Long story short:
  1. In the test options, use the filters or search box to narrow your choices and find the test you want.
  2. If you need a hand navigating through options, text our super friendly support team at 754-799-7833, and we'll provide tailored suggestions to help you find the ideal test.
  3. Once your order is placed, we’ll create your doctor’s lab order remotely, without any need for you to make a trip to a doctor in person or to talk to the doctor. Expect to receive your doctor’s lab order right in your inbox. It will also be in your patient portal if you need to find it later. We’ll also include instructions regarding fasting and other requirements for your test. Your patient portal will be auto-created hassle-free during checkout.
  4. If this is your first time ordering, you'll be prompted to create a password for instant login access to your patient portal. It's a quick way to conveniently access your orders and results whenever you want.
  5. When you’re ready, visit one of our 4,000 locations. Just bring your ID – no printing or faxing of your lab order is needed, as your order and details will already be in the lab system.
  6. Note that most lab locations don’t accept walk-ins, so it’s best to book an appointment in advance. Don’t worry – we’ll provide detailed instructions along the way.
  7. You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy!
  8. If you have any questions, please text us at 754-799-7833 or email [email protected] and we'll gladly help you.
How do I know which test to get?
In the test options, find the test you want. If you’re not sure which test to get, we can lend a hand in finding the right option.

Just text or call us at 754-799-7833, email us at [email protected], and we'll gladly help you. We've got your back and reply quickly.
Is it possible to make changes to my lab order if I made a mistake with the name, date of birth, or any other details?
Absolutely! We totally understand that errors can happen. No worries, we're here to help you.

Just reach out to us via text at 754-799-7833 or shoot us an email at [email protected]. Remember to include your order number and let us know the correct information you’d like to update. Our awesome team will jump right in and make sure everything is sorted out and accurate for you.

There are no changes necessary if your address is wrong on the requisition though. We don’t mail anything out.

Our lab requires an address to be listed to generate an order.
Do you accept health insurance?
Only HSA & FSA is accepted.

Our services are strictly self-pay and cannot be submitted to your health insurance provider except for Health Savings Accounts or Flexible Savings Accounts.

This policy applies to all insurance companies, including federal health insurance programs like Medicare.

If you have any questions, please text us at 754-799-7833 or email [email protected].
Can I cancel my order?
Yes.

We get it – sometimes your needs change.

As long as your samples haven’t been collected yet, we’re happy to help you cancel your order.

If you have any further questions, please text us at 754-799-7833 or email [email protected].

You can read more about our cancellation policy here.
How can I find a lab location near me?
During the ordering process, you’ll be able to select a specific lab near you, with no strings attached! You can switch it up later easily and visit any of our authorized locations as long as it’s the same lab company you selected your test for (Quest Diagnostics or Labcorp).

Before you proceed with your order, feel free to browse through all our lab locations here. This will give you the peace of mind of knowing that there's a lab nearby your home, office or your favorite gym.

If you have any questions, please text us at 754-799-7833 or email [email protected] and we'll gladly help you.

Here’s why 1,000,000+ customers chose us for affordable hassle-free private blood testing.

You get clinical lab reports & simplified health insights.
Save time & gas, go straight to the lab. Our doctors cover the rest.
Results start landing the next day after your lab visit.*
We don’t sell or share your data. Your time & privacy matter.
US-licensed doctors have your back if things get unclear.
No hidden fees, nice discounts for regular checkups.
Save a trip to the doctor, go directly to the lab
Instant orders, results often overnight*
Results explained in simple language
Reviewed by US licensed doctors
Fast & confidential, we never sell or share your data
No insurance needed, transparent pricing
Demo results
Reverse T3 28.5 ng/dL
Demo results
Low Optimal 9.2 - 24.1 High
28.5 ng/dL

What this means

Your Reverse T3 level is elevated above the optimal range, which suggests your body is converting more thyroid hormone into this inactive form. This can block your active thyroid hormone from working effectively, potentially explaining symptoms like persistent fatigue, difficulty losing weight, or feeling like your metabolism has slowed down.

* Regular blood test results (e.g., CBC) typically start arriving the next business day after sample collection. More complex tests, such as hormone panels, may take up to 10–15 business days due to their complexity.
Here’s how easy it is to get blood work done on your terms
Choose a checkup
Order your test Save a trip to the doctor. Your results will come with clear, friendly explanations. Takes 2 minutes
Book a lab
Book an appointment Visit any of our 4,000 nearby lab locations to have your samples collected. Book or walk-in
Choose a checkup
Get results Receive a clear, easy-to-digest health report by email & SMS within a few business days. Get answers, fast

Blood Test for Persistent Fatigue and Slow Metabolism

Google
3,138 reviews
  • Pinpoint the cause of your fatigue
  • Reveal hidden thyroid imbalances effortlessly
  • Clarify why your metabolism feels off

1,000,000+ blood tests later, here's what our customers say

Google reviews 3138 reviews Next
Still got questions? Text our super-cool support team at 754-799-7833 to get help finding your ideal checkup.