04/16/2026
Thyroid hormone therapy is not one-size-fits-all. RC Compounding's medications allow for precise, personalized dosing and formulation to better match each patient’s unique needs. Below are the key differences and benefits of commonly compounded sustained-release thyroid options:
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T3 Sustained-Release (SR) Capsules
- Active ingredient: Liothyronine (T3)
- T3 is the active form of thyroid hormone, responsible for immediate metabolic effects at the cellular level.
Benefits:
- Faster symptom relief for fatigue, brain fog, and low energy
- Ideal for patients who have difficulty converting T4 into T3
- Sustained-release formulation helps avoid spikes and crashes often seen with immediate-release T3
- May reduce side effects like palpitations or anxiety when compared to standard T3 dosing
Best suited for:
- Patients with poor T4-to-T3 conversion, persistent hypothyroid symptoms despite T4 therapy, or those needing fine-tuned metabolic support.
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T4 Sustained-Release (SR) Capsules
- Active ingredient: Levothyroxine (T4)
- T4 is a prohormone that converts into T3 in the body, providing a steady and stable thyroid hormone supply.
Benefits:
- Consistent hormone levels with reduced peaks and troughs
- Customized dosing not available in commercial products
- May improve tolerability in patients sensitive to fillers or dyes in manufactured medications
- Sustained-release delivery can promote more physiologic hormone conversion
Best suited for:
- Patients who do well on T4 alone but require customized dosing, improved tolerability, or smoother hormone delivery.
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Combination T3/T4 Sustained-Release Capsules
- Active ingredients: Liothyronine (T3) + Levothyroxine (T4)
- This option combines both thyroid hormones in a customized ratio to better mimic natural thyroid function.
Benefits:
- Balanced, physiologic approach to thyroid replacement
Personalized T3:T4 ratios tailored to individual lab values and symptoms
- Sustained-release formulation helps maintain stable energy and mood throughout the day
May improve outcomes in patients who remain symptomatic on T4 alone
Best suited for:
- Patients seeking a more natural balance of thyroid hormones or those who have not achieved optimal results with T4-only therapy.