What is Synthroid? Made by Abbott Laboratories, it’s the most well-known brand name for what’s called levothyroxine sodium, a synthetic, man-made version of the thyroid hormone T4.

Technically, it’s a synthetic crystalline L-3,3′,5,5′-tetraiodothyronine sodium salt. Doctors have been prescribing Synthroid for over 50 years to treat hypothyroidism. Before that time, the only treatment for hypothyroidism was natural desiccated thyroid, which appeared to work well for a good seven decades before Synthroid entered the arena.

Inactive ingredients include acacia, confectioner’s sugar (contains corn starch), lactose monohydrate, magnesium stearate, povidone, and talc. These may be different in other brands. The Synthroid brand sizes range from 25 mcg to 300 mcg synthetic T4.

What is T4? T4 is one of five hormones made by the thyroid– the latter which includes T4, T3, T2, T1 and calcitonin. T4 is a storage hormone with the purpose of converting to the active hormone T3, though the thyroid also makes some direct T3. T3 is the hormone which gives health and energy to every cell in the body.

What are other brands similar to Synthroid? Levoxyl, Levothroid, Unithroid, Berlthyrox, Eltibio, Eltroxin, Eutroxsig, Oroxine, Droxine, Eferox, Elthyrone, Euthyrox, Eutirox, generic levothyroxine, and more. They can have different fillers.

What’s the history of Synthroid or T4-only medications? This is covered in Chapter One of the revised Stop the Thyroid Madness book with interesting detail.

Is Synthroid an adequate treatment for hypothyroidism? A large and growing body of thyroid patients around the world have exclaimed “No!”, as discovered in their discussion in a variety of thyroid patient groups on the internet the past decade. Why? Because patients report continuing hypothyroid symptoms in their own degree and kind, sooner or later, which can include lingering fatigue, the need to nap, poor stamina or strength, depression, rising cholesterol or blood pressure, dry skin or hair, digestive problems, easy weight gain, difficulty losing weight, a diagnosis of Chronic Fatigue Syndrome or Fibromyalgia, brain fog, anemia, low B12, adrenal issues and many more.

Browse this compiled, patient-reported list of lingering or worsening symptoms while on Synthroid or similar T4-only meds, and which only went away when they switched to a different thyroid medication with desiccated thyroid. The kinds and severity are unique to each individual.

Is there an issue with Synthroid being synthetic?  In a particular STTM blog post written by Janie Bowthorpe in 2012, she refers to an article with an interesting viewpoint, stating that synthetic T4-only medications like Synthroid are “unfortunately a mix of the “left handed” nature-made combination of molecules, aka L-(Laevorotary), along with the synthetic, man-made “right handed” version, aka D-(Dextrorotary), i.e. the latter is a mirror-image, not a direct image.” As a result, one ends up with a lot of waste products, states the author of the article, and not the true T4. She presents it as food for thought.

Where can more information about the problem of T4-only meds be found?  The T4-only Meds Don’t Work page gives a good outline of why these medications don’t work and why.

Chapter One in the revised Stop the Thyroid Madness book also contains more details of the problem of Synthroid or other T4-only medications.

If a patient doesn’t want to be on Synthroid or other T4-only meds, what’s another choice?  Patients report getting far better results with Natural Desiccated Thyroid hormones.