This page is reference information only. Most compounds described here are research chemicals, not FDA-approved medications. MyTRT does not sell, recommend, or endorse the use of these substances. Always consult a qualified physician.
Levothyroxine (T4)
Thyroid Hormone Replacement
/WHAT_IT_IS
Levothyroxine is a synthetic form of the thyroid hormone thyroxine (T4), used as a long-term replacement therapy for hypothyroidism.
/USAGE
Prescribed for hypothyroidism, myxedema coma, subclinical hypothyroidism, and TSH suppression in thyroid cancer or goiter; off-label in some research for metabolic or weight-related studies.
/MECHANISM_OF_ACTION
Serves as a prohormone that converts peripherally to the active T3; T3 enters the nucleus and regulates gene transcription via thyroid hormone receptors :contentReference[oaicite:1]{index=1}.
Reported Benefits
- +Normalizes thyroid hormone levels and basal metabolism
- +Alleviates symptoms of hypothyroidism (fatigue, cold intolerance, weight gain)
- +Supports fetal development in pregnancy
- +Suppresses TSH in cases of goiter or thyroid cancer
Reported Side Effects
- −Symptoms of over-replacement: palpitations, anxiety, insomnia
- −Weight loss or gain
- −Hair loss, heat intolerance, tremor
- −Long-term overtreatment may lead to atrial fibrillation and bone density loss :contentReference[oaicite:2]{index=2}
- −Allergic reactions are rare
/STACKED_WITH
/RESEARCH_NOTES
Once-daily dosing achieves relatively stable levels after ~6 weeks. Protein binding >99%; adjustment needed for drugs/foods that affect absorption (e.g., calcium, iron, coffee) :contentReference[oaicite:4]{index=4}. Over-treatment in elderly increases risk of osteoporosis and atrial fibrillation :contentReference[oaicite:5]{index=5}.
/REFERENCE
https://pubmed.ncbi.nlm.nih.gov/nbk585644/Browse all 89 in the app.
MyTRT's in-app library has the same 89 peptide entries plus dosing notes, stack builders, and the ability to log them alongside your TRT protocol.