What's this test for?

This test is ideal if you're experiencing unexplained fatigue, struggling with weight despite diet and exercise, or feeling unusually cold or warm. It measures T3 thyroid hormones that directly control your metabolism, energy production, and body temperature regulation. Many people use this test when they suspect thyroid issues are affecting their daily energy and weight management but want specific answers about their T3 levels.

What happens after I get my results?

You'll receive detailed doctor notes in simple language explaining what your T3 levels mean for your energy, metabolism, and overall health. These notes include personalized recommendations like dietary adjustments, supplement suggestions for thyroid support, or whether you should follow up with an endocrinologist. You'll also get the standard lab report and can track your thyroid hormone levels over time using our trends feature to see how your interventions or treatments are working.

What's included in this test?

This panel measures Total T3 and Free T3 (the active form your body can use immediately). Together, these measurements reveal how well your thyroid is producing active hormone and whether your body is converting it properly. This helps identify why you might be experiencing fatigue, weight issues, or temperature sensitivity even when other thyroid markers seem normal.

How should I prepare for this test?

No special preparation is typically required for this test. You can eat and drink normally before your blood draw. However, if you're taking thyroid medication, try to schedule your test before taking your daily dose for the most accurate results. Let the lab know about any medications or supplements you're taking.

Who should consider getting this test?

This test is valuable for anyone experiencing persistent fatigue, unexplained weight changes, mood swings, or feeling too hot or cold. It's especially important if you have a family history of thyroid disease, are already on thyroid medication and want to monitor your levels, or have had normal TSH results but still experience thyroid-like symptoms.

What symptoms indicate I may need this test?

Common signs include constant tiredness that doesn't improve with rest, difficulty losing weight despite healthy eating and exercise, feeling unusually cold or having cold hands and feet, brain fog or trouble concentrating, thinning hair, dry skin, or irregular menstrual periods. If you're experiencing several of these symptoms together, checking your T3 levels can provide valuable insights.

How can I naturally support my thyroid function?

Supporting healthy T3 levels starts with ensuring adequate selenium intake through foods like Brazil nuts, eggs, and fish, as selenium helps convert thyroid hormones to their active form. Include iodine-rich foods like seaweed, seafood, and dairy, and zinc from pumpkin seeds and shellfish. Managing stress through meditation or yoga, getting 7-8 hours of quality sleep, and avoiding excessive processed foods can also help optimize thyroid function.

What is T3 and why does it matter?

T3 (triiodothyronine) is the active thyroid hormone that directly affects almost every cell in your body, controlling how fast you burn calories, how warm you feel, and how much energy you have. While your thyroid makes mostly T4, your body converts it to T3, which is the hormone that actually does the work. Low T3 can explain why you feel tired and gain weight even when other thyroid tests look normal.

What does low T3 mean?

Low T3 levels can indicate your thyroid isn't producing enough hormone or your body isn't converting T4 to T3 efficiently. This often causes fatigue, weight gain, feeling cold, brain fog, and sluggish metabolism. Low T3 can result from thyroid disease, chronic stress, nutritional deficiencies, or certain medications that interfere with hormone conversion.

How often should I retest my T3 levels?

If you're starting or adjusting thyroid medication, retest every 6-8 weeks until your levels stabilize and symptoms improve. Once your T3 is stable, testing every 6-12 months is common for ongoing monitoring. If you're testing for the first time and results are normal but symptoms persist, your doctor may recommend retesting in 3-6 months or checking additional thyroid markers like TSH and T4.

Getting your blood test with us is easy, private & backed by the power of science.Long story short: In the test options, use the filters or search box to narrow your choices and find the test you want. 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. 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. 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. 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. 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. You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy! If you have any questions, please text us at 754-799-7833 or email support@privatemdlabs.com 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 support@privatemdlabs.com, and we'll gladly help you. We've got your back and reply quickly.

When will my lab results be available?

Most test results will be available within 1–3 business days. Once they're ready, we'll send an email and text message to let you know. After your blood draw, just hang tight and don't worry – we'll keep you updated and in the loop! If you have any further questions, please text us at 754-799-7833 or email support@privatemdlabs.com, and we'll gladly help you.

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 support@privatemdlabs.com. 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 support@privatemdlabs.com.

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 support@privatemdlabs.com. 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 support@privatemdlabs.com and we'll gladly help you.

T3 Thyroid Test - Weight & Energy Issues

Getting your blood test with us is easy, private & backed by the power of science.

Long story short:

In the test options, use the filters or search box to narrow your choices and find the test you want.
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.
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.
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.
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.
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.
You’ll get your results via email & SMS and dive into understanding your body better. Yup, that easy!

754-799-7833

[email protected]

Thyroid Test for Weight Struggles and Constant Tiredness

Tri-iodothyronine (T3) Total and Free (FT3)

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

What's this test for?

How should I prepare for this test?

What's included in this test?

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

Thyroid Test for Weight Struggles and Constant Tiredness

90 day happiness guarantee

Prescription & fees included

Easy to understand results

Fast & convenient

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