Thyroid Gland & Follicles: How Thyroid Hormones Are Stored

The thyroid gland stores its product, thyroid hormones, in follicles. The thyroid hormones, thyroxine (T4) and triiodothyronine (T3), are stored in the colloid, a gelatinous substance that fills the follicles. When the body needs thyroid hormones, the follicular cells release the colloid into the bloodstream, where the thyroid hormones can be taken up by cells throughout the body.