Why do Armour Thyroid from Forest (manufacturer) 15mg tablets smell bad (they stink)?

Armour (natural) thyroid is made from actual pork thyroid. I have been on it or 60 years (I am an 81 year old retired nurse) and find it is the only thyroid supplement that works for me.
The "porky"odor you smell is from the actual pork gland that the tablet is made from. It is a good sign that you have gotten the authentic product. For several months I was given a generic--that had no smell at all and was white--not tan colored and I knew I was receiving an extremely diluted product. My hair began to fall out in alarming amounts and I was exhausted all the time. My TSH soared to 8 from 1.8--showing I was getting no thyroid supplement whatsoever. I changed pharmacies and they ordered from Forrest and when I opened the bottle and smelled the pork odor--I knew I had a very "pure" product. After 6 weeks on it-- my TSH returned to 1.8 and my hair stopped falling out completely.
Just a hint--I keep my bottle in the freezer of my frig--which reduces the odor. Try it--I think
you will find it helpful.

I'm not sure where the odor comes from. I have smelled them so I know what you are talking about. (Yuk!) That is why I take Nature-Throid instead, which has no odor, although both meds contain thyroid hormones made up from porcine (pig) glands, which makes them "natural desiccated thyroid meds". It is very similar to Armour, but Nature-Throid is made up of hypo-allergenic fillers, so it is a "cleaner" medication. You could ask your doctor about switching you to that one instead.