Does Thyroid Medication Cause Bone Loss? What the Research Says

Does Thyroid Medication Cause Bone Loss? Here’s What Research Shows

Levothyroxine is a synthetic hormone commonly prescribed to treat hypothyroidism. While effective in managing thyroid function, research indicates that its use, even within standard treatment guidelines, may be linked to bone density reduction.(1)

A study presented at the Radiological Society of North America (RSNA) annual meeting found that older adults on levothyroxine experienced greater bone loss over time compared to non-users. This association persisted even when thyroid-stimulating hormone (TSH) levels were within the normal range.(2)

Similarly, a study published in JAMA Internal Medicine reported that long-term levothyroxine therapy was associated with an increased risk of hip fractures, highlighting the potential impact on bone health. (3)

Thyroid hormones play a crucial role in bone metabolism, strength, and renewal. However, when medication suppresses TSH too much or leads to imbalanced hormone levels, it can increase the risk of bone loss and fractures, particularly in women.

A long-term study from the Baltimore Longitudinal Study of Aging found that even in euthyroid individuals (those with thyroid hormone levels within the reference range), those taking levothyroxine (T4) experienced greater bone loss over time. (4)This was especially true for people with:

• Higher Free T4 (FT4) levels
• Suppressed TSH
• Poor T4-to-T3 conversion (low Free T3 levels)

This raises an important question: Are standard thyroid medication protocols contributing to bone loss in some individuals?

How Low TSH & High T4 Affect Bone Health

TSH (Thyroid-Stimulating Hormone) isn’t just a marker of thyroid health, it also plays a role in bone remodelling.

When TSH is suppressed too much (often due to high doses of levothyroxine), it can:

• Increase bone turnover – Meaning bones break down faster than they rebuild.
• Reduce bone mineral density (BMD) – Particularly in postmenopausal women and those with pre-existing risk factors for osteoporosis.
• Raise fracture risk – Especially in areas like the hips and spine.

This doesn’t mean that everyone on thyroid medication will experience bone loss, but it highlights the importance of monitoring Free T3, Free T4, and TSH together - rather than relying on TSH alone.

Why a Full Thyroid Panel Matters for Bone Health

Most conventional doctors only test TSH to determine whether your thyroid is functioning properly. However, TSH alone doesn’t give the full picture - especially when it comes to bone health.

A full thyroid panel should include:

• TSH – To check for suppression (but not in isolation).
• Free T4 & Free T3 – To assess active thyroid hormone levels.
• Reverse T3 (rT3) – To see if inactive thyroid hormone is building up.
• T3 Uptake – To evaluate how well your body is absorbing T3.
• Thyroid Antibodies (TPO, TG, TRAb) – To screen for autoimmune thyroid disorders like Hashimoto’s and Graves’ disease.

How to Prevent Bone Loss While Taking Levothyroxine

If you’re taking levothyroxine (T4-only medication) or have low TSH, here are steps you can take to support your bone health:

1. Regular Monitoring

Ensure that TSH levels are maintained within the target range to avoid over-treatment.​ (5) However, you'll want to get the right thyroid tests

• If you’ve only had TSH tested, consider getting a Complete Thyroid Panel to get a more accurate assessment.
• Ensure optimal Free T3 levels - since T3 plays a role in calcium metabolism and bone strength.
• Download my FREE Thyroid Labs Cheat Sheet Here
• Order a Complete Thyroid Panel to Get Real Answers

2. Support T3 Conversion for Better Bone Health​

• Ensure adequate selenium and zinc intake – These help convert T4 into active T3.
• Manage stress & cortisol levels – Chronic stress can block T3 production and increase bone loss.
• Consider a more personalised thyroid treatment approach – Some individuals benefit from T3-containing medication (like liothyronine or NDT) rather than T4 alone.

3. Focus on Bone-Strengthening Nutrients

• Calcium & Vitamin D – Essential for maintaining strong bones.
• Magnesium – Helps regulate parathyroid hormone (PTH) and supports bone mineralisation.
• Vitamin K2 – Directs calcium to the bones instead of soft tissues.

Want a meal plan rich in bone-supporting nutrients? Check out my 7-Day Thyroid-Optimising Meal Plan → HERE.

4. Monitor Your Thyroid & Bone Health Regularly

• If you’re on long-term thyroid medication, you may wish to discuss with your healthcare provider the possibility of periodic bone density scans (DEXA scans) to monitor bone health.
• Work with a practitioner who understands functional thyroid health and can help you assess whether your medication, dosage, and thyroid levels are truly optimal.

5. Exercise

• Engage in weight-bearing exercises to enhance bone density.​

Final Thoughts

While levothyroxine is essential for managing hypothyroidism, it's important to be aware of its potential implications for bone health.

Not everyone on thyroid medication will experience bone loss, but it’s important to be proactive, especially if you have risk factors for osteoporosis.

Collaborate with your healthcare provider to monitor and mitigate risks, ensuring both effective thyroid management and the maintenance of strong bones.​

Key Takeaways:

• Low TSH and high Free T4 levels are linked to bone loss - especially in women.
• A full thyroid panel is essential - not just TSH!
• Optimising Free T3 levels may help protect bone density.
• Diet, lifestyle, and targeted supplementation play a crucial role in supporting both thyroid function and bone health.

Next Steps: Get the Full Picture of Your Thyroid Health

Want a full thyroid panel to assess your bone & thyroid health?

• Download my FREE Thyroid Lab Cheat Sheet to learn exactly which tests to ask for and start getting real answers.

Need expert analysis of your thyroid levels?

• Order a full thyroid panel + expert interpretation here.

Want a thyroid- and bone-supportive meal plan?

• Check out my 7-Day Thyroid-Optimising Meal Plan HERE.