Some people feel better switching from levothyroxine to Armour Thyroid (natural desiccated thyroid, or NDT). Armour contains both T4 and T3, so dosing and monitoring work a bit differently. This quick guide gives clear, usable tips on starting doses, common conversions, monitoring labs, and safety signals to watch for — but always do changes with a prescriber.
Armour comes in tablets measured in milligrams (15, 30, 60, 90, 120 mg); older labels also use grains where 1 grain = 60 mg. A typical starting approach looks like this: if you’re young and otherwise healthy, many prescribers start around 60 mg (1 grain) daily and adjust. If you’re older or have heart disease, doctors often start much lower (15–30 mg) and raise slowly.
Pregnancy, breastfeeding, and serious heart conditions need special handling. Women who are pregnant usually need close monitoring and often a different dosing plan — don’t try to adjust on your own.
There’s no perfect conversion, but common clinical approximations help when switching. Many clinicians use this rough guide as a starting point, then adjust by symptoms and labs:
- Levothyroxine 100 mcg → Armour about 60 mg (1 grain)
- Levothyroxine 125 mcg → Armour about 90 mg
- Levothyroxine 150 mcg → Armour about 120 mg
Because Armour contains T3, some patients react faster (good or bad). That’s why most providers recheck labs sooner after a switch.
How to adjust: increase or decrease by 15–30 mg every 4–6 weeks based on symptoms and lab results. If you get palpitations, anxiety, sweating, or insomnia after a dose increase, contact your prescriber — those can be signs of too much thyroid hormone.
Monitoring: check TSH (and often free T4 and free T3) about 6–8 weeks after any dose change. TSH lags, but labs plus how you feel give the best picture.
Timing and interactions: take Armour on an empty stomach for consistent absorption. Avoid calcium, iron, and some supplements within four hours of your dose. Keep a steady routine — different timing can change blood levels.
Storage and safety: store at room temperature, keep it out of reach of children, and don’t share thyroid meds. If you suspect overdose (rapid heartbeat, chest pain, severe tremor), seek immediate care.
Final note: Armour can work well for some people, but it needs individualized dosing and lab checks. Use the conversion tips above only as a starting point, and make every change with a prescriber who will monitor symptoms and labs closely.
