Nature-Throid is made by RLC Labs located at 1850 E Riverview Dr, Phoenix, Arizona. RLC labs manufactures, labels and distributes porcine-derived thyroid drug tablets for human use under the brand names of Nature-Throid and WP Thyroid.

Nature-Throid is a natural desiccated thyroid replacement therapy obtained from pig thyroid glands that is a prescription medicine. First released in the 1930s, it was one of the first available medications for hypothyroidism. It contains T4 & T3 replacement hormones and is available in 11 strengths ranging from ¼ grain (16.25 mg) to 3 grain (195 mg). It also contains naturally occurring thyroid cofactors T1, T2, calcitonin, and iodine (in trace amounts). Nature-Throid is not FDA approved.