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2001/07/01, 06:49 PM
by Dr. Ron Mendel
I recently heard a radio advertisement promoting human growth hormone (hGH) therapy to reverse aging. That’s right…reverse aging! It’s even endorsed by a physician, so it must be legit, right? Anyway, it made me think that perhaps I could be, like, 10 years old again, and that by the time I die, I will only be 50.
The doc wasn’t trying to sell the stuff to bodybuilders hoping to pack on 50 pounds of contractile protein, but as an anti-aging product only. My interest was certainly peaked when he started mentioning the amino acids (AA) used in formulation of the product, so I checked out the website mentioned. Let’s just say that I saw the price and determined I couldn’t afford to be young again. So I continue my search for over-the-counter hGH secretagogues which hopefully will increase synthesis of protein, promote new cell growth, and help slow the inevitable process of aging.
Let’s quickly review where we have been with hGH. In the 80s, arginine and ornithine were the hot thing. Arginine, commonly used in a clinical setting to test pituitary GH secretion, was being used orally with inconsistent results (10,15,34). Intravenous dosage and oral dosage is like apples and oranges (i.e. not the same) and I don’t think diarrhea was the desired effect. The addition of ornithine and lysine also resulted in poorly reproducible results (26,15,34,47). Speculation exists that at least 5-10 ng / L of hGH must be present during pituitary surges for physiological changes (46). Nutraceutical attempts at altering GH secretion often come up short (10,15,34). So where does the answer lie?
As it turns out, there is research from as far back as the 70s on effective, orally administered growth-hormone releasing peptides (GHRPs) (3,5,16,31). GHRPs are peptide chains, 3-7 amino acid residues in length. In fact, 20-40 mg p.o. (by mouth) of synthetic GHRP actually stimulates a sizable amount of growth hormone secretion! With the variety of "androgen precursors" on the market, why not a GH precursor? Technically, the GHRP products claim to stimulate endogenous production as opposed to providing actual substrate. They do so by interacting with specific receptors at both the pituitary and hypothalamic level.
As it turns out, non-peptide growth hormone secretagogues also exist, and were developed based upon the structure of GHRP’s, and possess improved bioavailability (12,19). Effects on growth-hormone release persist for approximately three hours for GHRP-2 (3), and up to 24 hours for non-peptide analogue (50). At any rate, it’s exciting that these drugs exist.
To up the ante, many over-the-counter growth hormone stimulators include herbs with known concentrations of naturally occurring L-dopa! Indeed, Mucuna pruriens and Vicia faba major (faba beans, broad beans) really do contain considerable amounts. Scientific literature validates this fact repeatedly (2,6,40,42,43,44,51,53). Of course, most bodybuilders are familiar with L-dopa’s ability to stimulate GH secretion (28,33,48,54). Many also know about its nasty side effects. Still, it’s not the levodopa that’s the centerpiece of modern GH booster products. It’s the "GHRP". Unfortunately, I have yet to see validation of a naturally occurring GHRP to augment the L-dopa in such products. It reportedly comes from the Lacuna bean. Broad beans. Lacuna beans. What’s up with the bean drugs? Clearly, Mother Nature has a graduate degree in pharmacology. And the 1994 DHSEA (Dietary Health Supplement Education Act) apparently makes the OTC sale of these preparations now legal. But before I allow myself to buy into all this stuff, I want validation on the "natural" GHRP source.
So what is the point of a discussion about GH boosters? Well, mostly, it’s about the marketing strategies and unscientifically based claims. I was often told by a very wise and stubborn man, “Just because it’s logical, doesn’t mean it is physiological.” Most marketing strategies are either so unbelievable that consumers actually do believe the claims, or the claims are so logical to the average supplement user that they would be fools not to use the product.
In the end, though, consumers can’t get legitimate, scientifically backed (referenced) information on what these products can actually do. Instead, they get miracle, cure-all bullshit about the wonders of human growth hormone. Often with references to studies that used injectable, recombinant hGH. Occasionally one can find data on IGF-1 elevation (after chronic GH booster administration); but nothing, to my knowledge, has been peer-reviewed. Besides, focusing solely on IGF-1 elevation as the singular purpose of GH therapy is somewhat misleading.
Consider the following. IGF-1 elevation is not always present during GH stimulation studies (1,9,17,30,41,52). IGF-1 can become depressed by internal and external factors that actually enhance GH secretion (e.g. estrogen and nutrition status) (24,11,14,27,36,49,55). And lastly, IGF-1 release is not the only interest of individuals looking to change body composition. All of growth hormone’s biological effects are not mediated by IGF-1. GH has physiologic effects of its own, eliciting changes that are quite different from those brought about by IGF-1 – notably, free fatty acid mobilization and lipolysis (22,32,38,39).
There is even evidence for a direct hypertrophic action of GH on muscle that is not mediated by IGF-1 (23). Furthermore, IGF-1 acts largely in a paracrine and autocrine fashion, exerting effects locally at the cellular level (13,25,45). Measuring blood concentrations doesn’t tell the whole picture. I’m not saying that measurement of IGF-1 is worthless: It’s actually quite good. What I am saying is, why not measure some other obvious variables? Why aren’t several GH-booster companies measuring acute release of actual growth hormone, like the Hexarelin studies do? It’s an indisputable way to directly compare. It should also be mentioned that none of the GH booster IGF-1 "data" reveal blood concentrations equivalent to those targeted by injectable rhGH therapy. Even if the manufacturer’s data is legit, plasma IGF-1 concentrations of up to 250 µg / ml fall well short of the 350 µg / ml target used during injectable GH therapy (35).
By the way, manufacturer excuses about the necessity of waiting several weeks to see increased IGF-1 concentrations may also not be legitimate. A single, acute bout of exercise can increase IGF-1 by 26 percent (4). Provided that real GHRP is a more potent GH stimulus than exercise (7,8,18,20,21,29,36,37), why do we have to wait several weeks to get an IGF-1 effect from GH-boosters? Gee, maybe we just need to fork over the additional cash for a two-month supply. Or maybe we need a six-month supply! After all, we’re willing to make the commitment to our bodies, right?
There is only one way to get to the bottom of over-the-counter GH boosters: Do the research! Hopefully it will be unbiased, well designed and well controlled. Until then, it is a guessing game. But be on the lookout for the good scientists who are searching for truth, justice and growth for all. They are out there. And the research is coming. I guarantee it.
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