One of the nurses I work with is concerned about her cousin, who's on a "human growth hormone diet." Apparently people are taking mail-order growth hormone to lose weight, which sounds pretty sketchy on several levels. Human growth hormone (HGH) is a serious drug; you have to inject it, and it can have serious side effects (see: acromegaly).
It's FDA-approved to treat growth hormone deficiency and a few other conditions in children and adults. I did a web search on HGH, and apparently this is a seriously big "health" fad.
It's illegal to sell real HGH without a prescription, so none of the "supplements" that turn up in a casual web search actually claim to contain any HGH, they only claim to induce your body to produce more of its own HGH. Oh, and they can be taken orally. But apparently these products, by tricking your body into producing extra growth hormone, are supposed to help you build muscle, lose weight, boost your energy...all these things to make your body all young and strong.
Sounds like a wonder drug...so how does it measure up scientifically?
Many of these advertisements are, interestingly enough, written from the perspective of a "skeptic" (example: http://hghlook.com/), so they do pay lip service to a few principles of scientific thinking. I found one page that summarized a study published in the New England Journal of Medicine; it claimed that this study controlled for other variables that could account for the subjects' weight loss and renewed energy (exercise, diet, etc.). This page did not link to the study, nor did it provide its title or the full name of its primary author, but who has time to look that stuff up, anyway? Numerous pages "helpfully" guide you through the morass of hoaxes and unacceptable options out there, guiding you to the supposedly safe and effective products they advertise.
Several of these products invoke a correlation between aging and a decline in growth hormone levels, implying (or, in most cases, stating) that a deficiency of growth hormone actually causes aging, and that restoring growth hormone will restore your youthful vigor. The advertisers are relying on us to forget that graying hair is also a symptom of aging, and that dyeing it back to its youthful hue won't actually make you younger.
Many of the pages dismiss real growth hormone as an unacceptable option because it is "synthetic," whereas their own products are proprietary blends of herbs and amino acids, and, in at least one case (http://xtreme-hgh.com/), GABA and L-Dopa...holy crap. They attribute the side effects of real HGH to its being "synthetic." The public should know that if these products really do raise your HGH, they would have the same side effects as the "synthetic" stuff (and probably a few more besides).
The "evidence" given for these products amounts to a large number of anecdotes; it's likely that individuals reporting positive results have experienced the placebo effect, or have misattributed the beneficial effects of other lifestyle changes to the supplement.
The funny thing is, there is a grain of truth in all of this growth-hormone replacement business. Though growth hormone deficiency gets more attention when it occurs in childhood, the condition can also develop in adulthood and cause some of the symptoms these products purport to treat: reduced muscle mass, low bone density, hair loss, reduced energy, high cholesterol. Of course, not everyone who has these symptoms has an actual growth hormone deficiency, and those who do will be better off getting real medical attention.