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drveejay11
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Finding The Right Replacement Dose When You Switch From Synthroid To Armour Thyroid.
http://www.drumlib.com/dp/000016.htm
Synthroid contains T4; however, Armour Thyroid contains T3 and T4. Thus, when a person switches to Armour, the fact that T3 is approximately four times as potent as T4 must be taken into account. Although this is a simple calculation, it can get confusing when they start talking about "grains" and "milligrams" and "micrograms." I surfed around quite a bit and I was surprised at how hard it is to find information on how to switch from Synthroid to Armour Thyroid. Well, it's really quite easy, so lets cut to the chase. (Actually, if you don't want to bother with the chase, I've got a conversion table at the bottom of the page.)
If you have been taking Synthroid, you probably hear the dosage referred to as micrograms (mcg). A common replacement dose is 150 mcg. This means that your Synthroid tablet contains 150 mcg of T4. Sometimes this is written as 0.15 mg, which equals 150 mcg. (1 mg equals 1000 mcg.) This is easier than it sounds -- just move the decimal point three places to the right. For example, 0.075 mg equals 75 mcg.
However, when you ask about Armour, they are going to start talking about either "grains" or "milligrams" (mg), but that's no problem: 1 grain equals 60 mg (milligrams). Pretty simple, right? But how much thyroid hormone is in it?
1 grain (60 mg) of Armour thyroid contains 9 mcg of T3 and 38 mcg of T4. Notice how we are already talking in terms of micrograms (mcg), just like with Synthroid. We are almost ready to compare apples with apples. OK, remember how T3 is approximately four times as potent as T4? Good! Multiply the 9 mcg of T3 times 4 and add that to the 38 mcg of T4:
36 mcg (9 mcg of T3 times 4)
+ 38 mcg of T4
----------------------------------
74 mcg
1 grain (60 mg) of Armour equals approximately 74 mcg of T4 (Synthroid)
Why do you say approximately?
Because there are so many variables involved in switching from Synthroid (T4) to Armour Thyroid (T4 and T3). In reality, we're still comparing apples and oranges because there are important differences between T4 and T3:
Absorption: T3 is absorbed better than T4. The bioavailability of T4 is influenced by food, fasting, age and malabsorption syndromes.
Peripheral Conversion: Enzymes convert T4 into biologically active T3. One of the things that affects the activity of these enzymes is sympathetic nervous system activity, which is known to be reduced in obese people.
Half-life: T3 has a much shorter half-life and its effects occur rapidly. This is why many people feel better when they take half of their Armour dose in the morning and the other half later in the day.
Thus, when switching from Synthroid to Armour, doctors will generally start you out at a low dosage and increase it gradually. Remember, the numbers are just a rough guide -- finding the right dose for YOU requires a doctor that will listen to how you feel as well as analyze blood tests and body temperature. For more information on the importance of body temperature, check out "Hypothyroidism: The Unsuspected Illness"
http://www.drumlib.com/dp/000016.htm
Synthroid contains T4; however, Armour Thyroid contains T3 and T4. Thus, when a person switches to Armour, the fact that T3 is approximately four times as potent as T4 must be taken into account. Although this is a simple calculation, it can get confusing when they start talking about "grains" and "milligrams" and "micrograms." I surfed around quite a bit and I was surprised at how hard it is to find information on how to switch from Synthroid to Armour Thyroid. Well, it's really quite easy, so lets cut to the chase. (Actually, if you don't want to bother with the chase, I've got a conversion table at the bottom of the page.)
If you have been taking Synthroid, you probably hear the dosage referred to as micrograms (mcg). A common replacement dose is 150 mcg. This means that your Synthroid tablet contains 150 mcg of T4. Sometimes this is written as 0.15 mg, which equals 150 mcg. (1 mg equals 1000 mcg.) This is easier than it sounds -- just move the decimal point three places to the right. For example, 0.075 mg equals 75 mcg.
However, when you ask about Armour, they are going to start talking about either "grains" or "milligrams" (mg), but that's no problem: 1 grain equals 60 mg (milligrams). Pretty simple, right? But how much thyroid hormone is in it?
1 grain (60 mg) of Armour thyroid contains 9 mcg of T3 and 38 mcg of T4. Notice how we are already talking in terms of micrograms (mcg), just like with Synthroid. We are almost ready to compare apples with apples. OK, remember how T3 is approximately four times as potent as T4? Good! Multiply the 9 mcg of T3 times 4 and add that to the 38 mcg of T4:
36 mcg (9 mcg of T3 times 4)
+ 38 mcg of T4
----------------------------------
74 mcg
1 grain (60 mg) of Armour equals approximately 74 mcg of T4 (Synthroid)
Why do you say approximately?
Because there are so many variables involved in switching from Synthroid (T4) to Armour Thyroid (T4 and T3). In reality, we're still comparing apples and oranges because there are important differences between T4 and T3:
Absorption: T3 is absorbed better than T4. The bioavailability of T4 is influenced by food, fasting, age and malabsorption syndromes.
Peripheral Conversion: Enzymes convert T4 into biologically active T3. One of the things that affects the activity of these enzymes is sympathetic nervous system activity, which is known to be reduced in obese people.
Half-life: T3 has a much shorter half-life and its effects occur rapidly. This is why many people feel better when they take half of their Armour dose in the morning and the other half later in the day.
Thus, when switching from Synthroid to Armour, doctors will generally start you out at a low dosage and increase it gradually. Remember, the numbers are just a rough guide -- finding the right dose for YOU requires a doctor that will listen to how you feel as well as analyze blood tests and body temperature. For more information on the importance of body temperature, check out "Hypothyroidism: The Unsuspected Illness"
