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How long should it take Synthroid (thyroxine) to start working?

1 doctor weighed in
Dr. Richard Shewbridge
Internal Medicine - Endocrinology

In brief: 2-5 days.

Synthroid (levothyroxine) has a very long half-life.
Levels start to rise in a few days, but take 5-6 weeks to reach a plateau.

In brief: 2-5 days.

Synthroid (levothyroxine) has a very long half-life.
Levels start to rise in a few days, but take 5-6 weeks to reach a plateau.
Dr. Richard Shewbridge
Dr. Richard Shewbridge
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