I called a man in Boston who was described to me as a “well-known physician.” He had extensive experience with a little-known substance called Smilax officinalis, which I understood was some kind of herbal concoction, but when I called “Dr. X”—he refused to divulge his real name—he told me that he wasn’t at liberty to provide any details about Smilax. It wasn’t until later that I found out that Smilax officinalis was actually sarsaparilla, a common flavoring in root beer. A search for the anabolic effects of the plant turned up one obscure connection related to natural compounds called plant sterols.
Flashback to 1942. A renegade chemist from the University of Pennsylvania named Russell Marker was acting like Indiana Jones, searching for plants with special properties in the wilds of Mexico. At the time, steroid hormones, including testosterone, were being produced in a very expensive process. Working in his lab in 1936, Marker successfully developed a method of producing chemical steroids from plant sterols. All steroids are made from the parent compound, cholesterol. When Marker noticed that plant sterols, which are the plant versions of cholesterol, have a close structural similarity to cholesterol, he was able to produce a human steroid from sarsaparilla. It was too expensive, though, to be used in mass quantities; hence Marker’s Mexican trek.
Marker found his ideal substitute in the Mexican yam. Diosgenin, a plant sterol in the yam, proved to be an effective substrate for steroid production. Through a five-step process involving the use of various enzymes, Marker successfully produced the steroid progesterone. The first major steroid produced from cholesterol, progesterone is the precursor of other steroid hormones, including estrogen and testosterone.
Marker offered his discovery to drug companies, but they all turned him down except for a small, little-known company called Syntex. Syntex eventually became a major producer of hormone drugs, including a number of anabolic steroids. Meanwhile, the Mexican yam and diosgenin became the major raw materials for steroid hormones, particularly birth control pills, until they were supplanted by a synthetic process in 1970.
Mexican yams were also sold as a food supplement because of their plant sterol content. In fact, early forms of supplemental DHEA primarily contained Mexican yam extract. That proved problematic, since the yam itself doesn’t contain any active steroid hormones, including DHEA. The poor quality and ineffectiveness of the supplements led to their removal from the market in 1987 by the Food and Drug Administration. Real DHEA turned up a few years later, thanks to the Dietary Supplement Health and Education Act of 1994.
It’s no secret that anabolic steroids help build muscle size and strength. The problem with steroids is twofold. First, they’re prescription drugs and have potentially serious side effects. Second, most doctors are loath to prescribe them, knowing how easily they can be abused by those seeking to build muscle. That led to the pro-hormone industry, which began with legitimate DHEA supplements and ended with the advent of the Anabolic Steroid Drug Amendment in 2005.
Not much better than DHEA, the initial pro-hormones were far worse from a health perspective. They offered little in the way of true anabolic activity but plenty in the way of anabolic-steroid-related side effects, including rapid conversion into estrogen. The last generation of pro-hormones was far improved, since many were actual anabolic steroids that were never released by the companies that researched them—and for good reason. Most of them had too many side effects, such as being hard on the liver. Even worse, evidence for significant anabolic effect in humans was lacking.
After the FDA banned pro-hormone supplements, supplement companies catering to bodybuilders and athletes were temporarily at a loss. What could they do to maintain their lucrative sales? A few threw all caution to the wind by attempting to sell a few more rejected steroid compounds, while others began to surreptitiously include a new category of steroids, called “designer steroids,” since they were supposedly not detectable by the usual drug screens. That proved short-lived, for the FDA was on the lookout for any substance that could directly convert into testosterone, which put it in direct violation of the 2005 steroid amendment.
Now, how to explain the current plethora of supplements advertised as boosting testosterone? What the supplement companies did amounted to going back in time. Most of the products are based on plant compounds, which makes them completely legal in the eyes of the FDA. The more important question is, Are they effective?
Some of the more unscrupulous companies resorted to highly questionable tactics. For example, many current pro-hormone supplements are based on DHEA, but it’s usually called something else. That’s a common tactic today—listing complex chemical names to make consumers believe that a supplement contains a new and revolutionary compound. Another likely motive is that the chemical nomenclature imparts a druglike aura to the product. DHEA is not junk; it benefits those whose bodies produce low amounts of it. As a testosterone-booster, though, it’s effective only for women.
Plants don’t actually contain real testosterone but rather plant sterols. The human body lacks the enzymes required to convert plant sterols into true steroids, although it can be done in a lab. That explains why plant sterols were—and in some cases still are—used to produce steroid drugs. One plant known to contain an actual androgen—the truffle—is a type of mushroom. Truffles naturally contain a very weak androgen called androst-16-en-3-ol. It isn’t very anabolic, which explains why you don’t see any mushrooms competing for the Mr. Olympia title.
Perhaps the foremost herbal testosterone booster is Tribulus terrestris, which grows wild in Bulgaria and elsewhere. Tribulus contains various plant sterols, including diosgenin. Most of the sterols are categorized as saponins, since they produce a soaplike effect when metabolized. The active anabolic ingredient in tribulus is a saponin called protodioscin.
Purveyors of tribulus often note that if it doesn’t contain enough protodioscin, it’s useless for building muscle, although it does have other properties, including diuretic effects and coronary artery dilation. Normally tribulus contains about 5 percent protodioscin. One study analyzed commercial tribulus supplements for their protodioscin content. It varied, with samples from Bulgarian sources having more and those from China and India the least. Quality control is a real problem with tribulus, as it is with many other herbal supplements.
Tribulus came to the attention of Western athletes after poorly controlled Russian research revealed that it increased testosterone. The initial studies involved animals, such as rams. In the human studies that followed, tribulus was given to men with clinically low testosterone levels. One study found that men receiving 750 milligrams of tribulus daily for five days showed a 72 percent increase in luteinizing hormone, along with a 40 percent rise in testosterone. Less publicized was the accompanying 81 percent rise in estrogen.
Luteinizing hormone is produced in the pituitary gland and governs the production of testosterone in the testes. It’s suggested that tribulus contains a substance called harmine that blunts the breakdown of an enzyme in the brain that degrades dopamine. Elevated dopamine encourages the production of not only luteinizing hormone and subsequent testosterone but also growth hormone. The much touted “active” tribulus ingredient, protodioscin, aids DHEA synthesis and release.
Based on these mechanisms, tribulus should indeed be an efficient testosterone booster, although increasing DHEA wouldn’t have much of an anabolic effect in young men. Animal studies seem to confirm the hormone-boosting effect of tribulus. One recent study, in which primates, rats and rabbits were given a tribulus extract intravenously, resulted in a 52 percent increase in testosterone, a 31 percent rise in the testosterone metabolite DHT and a 29 percent rise in DHEA-S in the primates. The rats in the study were castrated but still experienced a 51 percent rise in testosterone. Rabbits didn’t fare as well, showing mainly a 32 percent increase in undesirable DHT.1 Another study showed that giving rats tribulus protected against diabetes through antioxidant activity.2
Animal studies can’t always be extrapolated to humans. While the research on tribulus emanating from Russia is nothing short of glowing, the herb hasn’t fared as well under Western scientific scrutiny. One study involved 15 men who got either a placebo or tribulus at a dose of 3.21 milligrams per kilogram of bodyweight daily. The subjects followed an eight-week weight-training routine. Muscle endurance increased on the bench press and leg press in the placebo group, while those in the tribulus group showed an increase only in leg press strength. No changes in body composition occurred in either group.3
Another study examined the effects of either a placebo or 450 milligrams a day of tribulus in 22 rugby players who were engaged in weight training for five weeks. Both groups produced similar gains, along with no rise in testosterone in the tribulus group.4 Still another study looked at whether tribulus raises testosterone in young men. The 21 subjects took either tribulus or a placebo for four weeks. Tribulus had no effect.5
Given that tribulus can raise estrogen, it’s not surprising that there’s at least one case study on record of a young bodybuilder who acquired gynecomastia, or male breast formation, after using a tribulus supplement.6 DHEA can easily convert into estrogen, particularly in younger men, although it more often converts into a metabolite of DHT.
One company is selling what it calls a “potent testosterone booster” based on the herb fenugreek. According to the company’s claims, substances in fenugreek called fenusides promote a significant rise in free, or active, testosterone. The company mentions a study in which 55 men, aged 18 to 35, all actively involved in weight training, were divided into two groups, with 29 receiving the fenugreek product and 26 getting a placebo. The subjects were evaluated three times over the eight-week course of the study. Those in the fenugreek group showed a 100 percent rise in free testosterone compared to the placebo group, along with a reduction in skin folds, pointing to lowered bodyfat.
Sounds impressive, until you realize that this was an unpublished study done by the company making the product. No other details of the experiment were mentioned. Interestingly, fenugreek contains some of the same plant sterols found in tribulus, including protodioscin, as well as diosgenin, which was as found in Mexican yams. It contains a unique amino acid called 4-hydroxyisoleucine that has an effect similar to insulin in aiding glucose uptake. One study of cyclists showed that fenugreek seemed to increase the efficiency of muscle glycogen repletion when taken with glucose, which is precisely what insulin does.
I’ll have more on testosterone boosters next month.
2 Lotfy, A.A., et al. (2006). The protective effect of tribulus terrestris in diabetes. Ann NY Acad Sci. 1084:391-401.
3 Antonio, J., et al. (2000). The effects of tribulus terrestris on body composition and exercise performance in resistance-trained males. Int J Sport Nutr Exerc Metab. 10:208-15.
4 Rogerson, S., et al. (2007). The effect of five weeks of tribulus terrestris supplementation on muscle strength and body composition during preseason training in elite rugby league players. J Str Cond Res. 21:348-53.
5 Neychev, V.K., et al. (2005). The aphrodisiac herb tribulus does not influence the androgen production in young men. J Ethnopharmacol. 101:319-23.
6 Jameel, J.K., et al. (2004). Gynecomastia and the plant product “tribulus terrestris.” Breast. 13:428-30.
©,2013 Jerry Brainum. Any reprinting in any type of media, including electronic and foreign is expressly prohibited.