This purple, round pill imprinted with SYNTHROID 175 is a Levothyroxine Sodium 0.175 MG Oral Tablet [Synthroid], per the NIH.
Synthroid is a human prescription drug. The active pharmaceutical ingredient is levothyroxine sodium and is classified as, "l-Thyroxine [EPC], Thyroxine [Chemical/Ingredient]."
This pill is made by a total of 4 firms: (1) Abbott Laboratories, (2) Aphena Pharma Solutions - Tennessee, Inc., (3) Physicians Total Care, Inc., and (4) Cardinal Health.
There is 1 other purple pill that with a similar imprint: "SYNTHROID 175". They may be a different dosage of the same drug or a different drug entirely.