> Vitamin D is a steroid hormone, in the same category as sex hormones like estrogen and testosterone, and glucocorticoids like the stress hormone cortisol. Steroid hormones are all made from cholesterol, and looking at their molecular structures, you can see the similarities
Does it matter that 2 different things have a similar molecular structure? Surely a tiny little difference can have a huge difference in how a substance interacts with our body?
It can, in this case our body can swap the "dangly bits" of cholesterol to something different like vitamin D. Aside from this, it also depends on the receptor in question. Some receptors can accept levo and dextro molecules even though they are mirrored and therefore different shapes, while some have higher affinity for one and the other basically doesn't fit at all.
Does it matter that 2 different things have a similar molecular structure? Surely a tiny little difference can have a huge difference in how a substance interacts with our body?