Why do you think they would cause your pituitary gland to grow?
Keep in mind that long terms studies of these medications being used in men are hard to come across. They just haven't been used in males for all that long in the grand scheme of things. You also have to consider that many guys using these meds aren't using them under the supervision of a doctor, so dosing is all over the place and we can't be certain that they're being used responsibly.
I'm not a doctor, so most of my info comes from anecdotal evidence and from reading studies performed in women and rats, but here's my two cents...
- HCG seems to be pretty safe when used responsibly and in low/moderate doses. Adverse effects only appear to arise if the patient is hypersensitive to hCG, or when high doses are used. It doesn't seem to have any negative effect on other bodily systems.
- SERMs, I don't think we can lump all of them into one category when evaluating their safety since not all of them work in the same manner. If being used to treat a serious condition, the benefits likely outweigh the potential side effects, but they aren't exactly benign. Are you going to get cancer from using a SERM for a few years? Unlikely.
It also depends on how the SERM is being used. Let's say a guy is using Nolvadex to reduce the chance of getting gyno. Since Nolvadex only blocks the estrogens in the breast tissues rather than actually reducing the amount of estrogens in the body, this guy is now putting himself at risk for the health issues that will arise from excess estrogens in his body.