What is considered normal various considerably depending on who you are talking to. Unfortunately endocrinologists and other doctors seem to practice these days based on Synthroid dogma, which teaches doctors that only TSH, a pituitary hormone, should be used to determine thyroid levels.
This has led many patients to have horrendous symptoms and long-term health consequences, when it would be more useful for many patients to measure FT3 (The active thyroid hormone), FT4 (The inactive hormone it converts from), reverse T3 (The inactive hormone that T4 sometimes converts to rather than T3), and TPO and thyroglobulin antibodies (which can affect use of thyroid hormones as the thyroid gland is being destroyed).
By doing these tests, one can figure out what a patient really needs to be able to optimize thyroid, which should optimize collagen production and bone health, according to the article. However, there are also a number of other factors affecting both that are not thyroid related.
The Thyroid Patients Canada blog and FB group has a lot of helpful information about thyroid management and thyroid health, based upon a huge amount of thyroid research.