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Enzyte: Effective or Not?

Tessa Kayser

October 4, 2009




The purpose of this paper is to determine whether or not Enzyte would actually work to improve male libido and sexual performance by researching the product and its ingredients.


What is Enzyte?

Enzyte is a male enhancement pill produced by Berkeley Nutraceuticals that claims to help men “reach peak sexual enhancement” by using herbal ingredients that are believed to “improve blood flow and circulation as well as enhance physical performance, including sexual stamina” (  The official website ( states that taking Enzyte as a daily supplement “can give you a lifetime of the strongest, most powerful erections imaginable.”  Additionally, the company offers a no-questions-asked return policy for any unopened packages.


What is the rationale behind Enzyte?

The rationale behind this product is relatively simple: increased blood flow in the penis will cause an erection, so herbs that are thought to increase blood flow will aid in creating better erections.  Some of the main ingredients, such as gingko biloba, are herbs that are believed to improve blood circulation.  Although the Enzyte website does offer descriptions of the main ingredients and their relevance to sexual enhancement, there is no concrete evidence provided by clinical trials specific to the product.


Who is providing this information and why?

Many websites presenting information about Enzyte are online stores for male enhancement products or for general nutritional supplements, so it is likely that they are presenting this information in order to make money off of it.  Herbal supplements are not regulated by the FDA or any other government agency like over-the-counter and prescription drugs, so any herbal supplements can be sold  “as long as they don’t make any health claims or say they cure a condition” (AARP).  Additionally, many websites offer success stories and testimonials – some of which are dramatizations rather than actual testimonials – but anecdotal evidence alone is not sufficient to determine if it is actually effective.


Does it work?

It is difficult to determine whether or not Enzyte is effective without in-depth research because vendor websites claim that it works wonders, whereas many herbal supplement blogs claim that the product is a scam or that it is not as effective as other similar products.  There have been no Enzyte-specific clinical trials, but there have been some unaffiliated human and animal trials using individual ingredients in the product.  Although researching individual ingredients does show some promising results, there is no evidence showing that the combination in Enzyte is more effective than taking any of the ingredients alone.  Also, do not assume that just because it is on the market, it is safe.  Because Enzyte is categorized as an herbal remedy, its manufacturers do not need to get approval from anyone before marketing the product.


Information gathered from internet searches

The company was sued in 2006

Enzyte was advertised as a penis enlargement pill and consumers were automatically billed without their consent for monthly shipments if they accepted the “risk-free” 30-day trial pack before a class action lawsuit for fraudulent business practices was filed against the pharmaceutical company that makes this product.  Attorneys General from 17 states alleged that “the defendants, in their advertisements, made claims about the effectiveness of their products that were not supported by reliable, competent scientific evidence” (  After settling for $2.5 million, the penis enlarging claim was removed from its labels and the company was required to provide restitution to consumers who were clandestinely billed.  Therefore, when searching for information about the product, you should ignore statements about its effectiveness


Internet claims

Most websites in favor of Enzyte agreed that this product is “the number one selling male enhancement pill on the market” (  Many websites also offer explanations about the ingredients and their supposed health benefits.  For example, one website states that “based on the supposed content of the tablets, it is possible that Enzyte may provide some benefit for improving impotence (erectile dysfunction) or for increasing sexual desire” (eMedTV).  This website even makes mild references to scientific studies that have suggested that ginseng, l-arginine, and maca root can improve impotence.  However, there were no citations or names of the studies, so this information should not be taken at face value.


In terms of Enzyte's efficacy, there are mixed reviews.  The website claim that “customers who use this product report that Enzyte results in harder erections, increased sexual stamina, and an increased libido” and that “the proprietary blend of herbal ingredients and amino acids in Enzyte are purported to foster greater blood flow to the penis, and improve overall sexual health.”  It also uses its popularity as evidence of its efficacy: “if it didn’t work, people would stop buying it.”  This statement is convincing, but it should not be taken as evidence because it is a bandwagon fallacy.  Just because “everyone else” is doing something does not mean that it is the correct thing to do.


Another website,, claims that the product is useless and makes the company seem highly unreliable because of its lawsuit.  It goes on to say that “Enzyte doesn't do squat and there is no proof that it does” and suggests that “If you can't get an erection you need to see a doctor and get Viagra.”  This webpage might cause some people to look into buying a different product like VigRx, which appears to be the website's sponsor.  There is even a link to buy VigRx Plus if you scroll down past the Enzyte section.  Although this website does cite Enzyte's lawsuit, it does not provide any testimonials or scientific evidence showing that the product would not work.


An article from the online version of USA Today was more believable because it included quotes from a urologist who said “it makes no sense medically. [...] There's no way that increasing blood flow to the penis, as Enzyte claims to do, will actually increase its size” (USA Today).  However, the article was simply providing a brief introduction to Enzyte and did not go much further than the few quotes from Dr. Kenneth Golberg.


There are also many websites that provide anecdotal evidence to support or oppose Enzyte's claims.  One website that sells Enzyte has a section at the bottom of the page for customer reviews.  There is a wide variety of responses ranging from rave reviews to strong opposition.  For example, one anonymous reviewer said “Enzyte works. Ignore what other people say. It really does,” whereas another said “Enzyte by Berkeley is a totally useless preparation. It not only increases irritability, but raises body temperature enormously” (


In short, until clinical trials are conducted specifically on Enzyte, there will always be opposing views on its efficacy, so you should look at more than just testimonials before deciding to try it.


Why should you try Enzyte?


Enzyte uses “Smiling Bob” as its representative customer in advertisements for the product.  In the holiday commercial, Bob is smiling the entire time because “he got the one thing that every lady likes” (YouTube).  The narrator explains to the audience (using euphemisms, of course) that Bob tried Enzyte and quickly noticed an increase in his penis size and sexual performance and that now all the women in his office are lining up to sleep with him.  The commercial is somewhat clever and would probably convince a lot of men to at least take a look at the product or get a free trial, even though there are no statements saying that it has been proven to work for customers other than the fictitious Smiling Bob.


Other websites try to convince the reader to try Enzyte by prodding at his insecurities.  For example, says that “at $49.95 for a month’s supply, it’s not exactly cheap, but most men would pay almost anything for the confidence that comes with a better sexual experience” and that “unsatisfactory sexual function can contribute to low self-esteem and relationship problems.”  These statements imply that if they take Enzyte, they will have better sex, self-esteem, and relationships, but they are not supported by any hard evidence.  Another website,, claims that “with Enzyte you won't get overnight promises, just proven, natural results that have been trusted for years.”  This claim would probably be convincing to many people, but it does not explain how it works or how it was proven to be effective.


If you really are concerned about your sexual performance, you should talk to your doctor about it to see if your sexual functioning is normal or if you have a more serious problem like erectile dysfunction.  If you thought your sexual performance was at least decent before seeing commercials for Enzyte, you probably don't need the pills.


How it works

According to, Enzyte is made of ingredients that “have been proven in clinical studies and human experience to increase blood flow to the penis, which is what creates and maintains an erection” (Free Press Release).  Similarly, explains that “all of the ingredients in Enzyte are associated in some way with having a positive effect on a man's sexual power, endurance or ability to perform” (Does Enzyte Really Work?).









Academic findings on the main ingredients

Enzyte has a large amount of ingredients, so I will only explore the main components that are highlighted on the official website.


Horny Goat Weed                                                                                                                                                   






© 2004 Calvin J. Hamilton


A study conducted by Makarova et al. (2007) aimed to support the use of horny goat weed, also known as Epimedium, as a treatment for male erectile dysfunction.  The study used oral administration on rats and included different dosage groups and two control groups to account for age.  They administered Epimedium suspended in wheat germ oil to active groups (old rats) and olive oil to control groups (old and young rats) and found that there was a significant increase in the frequency of intercourse and ejaculations in rats who were given Epimedium for ten days.  This study found that when suspended in wheat germ oil, horny goat weed extract “enhanced sexual potency in normal young rats and in aged rats significantly.”  The behavioral measures were in accordance with Guideline on Experimental (Pre-clinical) Studying of New Pharmacological Substances (2005) and standard procedure for sexual behavior studies in rats.  This study provides scientific evidence showing that horny goat weed extract may be used to improve sexual potency; however, it might not have the same effect on humans and it might not have the same effect when mixed with other herbal extracts, so it is better viewed as a promising remedy that requires more testing.


Korean Red Ginseng


Hong et al. (2002) conducted a double-blind study on 45 patients to determine the efficacy of Korean red ginseng in treating erectile dysfunction and found that it has the potential to be an alternative treatment for the condition.  In this study, one group was given 2700mg of red ginseng daily and the other was given a placebo.  Neither of the groups knew what treatment they were receiving, so there was no bias in the survey responses.  The measures included “the International Index of Erectile Function, RigiScan (UroHealth Systems, Laguna Niguel, California), hormonal levels and penile duplex ultrasonography with audiovisual sexual stimulation.”  This was a crossover study, which means it included 8 weeks of treatment, 2 weeks of non-treatment, and 8 more weeks of treatment.  The preliminary findings supported the belief that Korean ginseng can be used to treat erectile dysfunction.  However, the study was only conducted on subjects clinically diagnosed with erectile dysfunction, so it does not necessarily account for men who simply want to improve their erections.  The researchers noted at the end of the paper that “studies of specific ingredients of this herb and longer treatment duration are necessary.”  Further research would also be necessary to determine if this herb would be effective in men without erectile dysfunction.


Ginkgo biloba

Jl Staub, July 16, 2008


Dr. Alan Cohen wrote a brief paper in 1996 about the effects of Ginkgo biloba extract on 5 patients with antidepressant-induced sexual dysfunction, or ASD.  At the end of 24 weeks, the effects of ASD were reversed with a daily dosage of 240mg of Ginkgo biloba extract and all 5 patients decided to continue treatment after the trial was completed.  However, the number of subjects was very low and there were no control groups, so further studies would be required to determine whether or not Ginkgo biloba is a suitable alternative treatment for ASD.  Also, because this study only included patients with ASD, it is uncertain as to whether or not this herbal remedy would work for improving sexual performance for individuals with normal sexual functioning.


Another study on Ginkgo biloba conducted on rats by Yeh et al. (2007) found that there was a significant increase in testosterone in rats who were given Ginkgo biloba in concentrations of 1000 μg/ml.  The study also found that Ginkgo biloba “significantly enhanced male copulatory behavior in rats” when they were given a dose of 50 mg of Ginkgo per kilogram of body weight.  The measures in this study were standard for copulatory behavior in rats and the four different groups were given different amounts of Ginkgo biloba extract (10, 50, or 100 mg/kg/day and a control group that was given distilled water).  This study is more relevant to the efficacy of Ginkgo biloba in Enzyte because the rats used in the study were sexually experienced and did not have any form of sexual dysfunction. 


Tribulus terrestris Extract

Forest and Kim Starr


The effect of Tribulus terrestris on sexual behavior was studied by Gauthaman et al. (2003) by administering different dosages of Tribulus to male rats.  The goal of the study was to “scientifically validate the claim of [Tribulus terrestris] as an aphrodisiac.”  Forty male rats were given oral doses of Tribulus at different concentrations (except for the control group) over a period of 8 weeks and the rats' weight and sexual behavior (using standard measures for copulatory behavior) were observed and recorded.  The researchers found that compared to the control group, weight gain and sexual improvement were significantly higher, which validates the claim that Tribulus is an aphrodisiac.  They believe that the herb increases the amount of androgens (hormones, such as testosterone, that aid in development of male characteristics), which cause more nitric oxide (a chemical closely tied to physiology of the penis) to be released, thereby improving sexual performance. 


In terms of Enzyte, this study would suggest that the Tribulus terrestris in the product would actually work to improve sexual behavior.  However, Dr. Arif Adimoelja wrote a brief paper in 2002 on his finding that many herbs, including Tribulus, might not contain their active ingredients if grown in the wrong type of soil.  He found that Tribulus “grown on different soils does not consistently produce the active component Protodioscin,” which is the aphrodisiac ingredient in Tribulus.  This means that if the Tribulus in your Enzyte pills are not grown in the appropriate soil, the active chemical in it will not be present and the herb will not have any effect on you.  This could be a reason why some customers claim that they had great success with the product and others complain that they didn't notice any difference.  These findings might also account for inconsistencies in the efficacy of Ginkgo biloba and ginseng.




In 1987, Knowles et al. published a paper concluding that l-arginine causes more nitric oxide to be created and released in the body.  This is significant to the discussion about Enzyte because as found in a 1997 study by Dr. Arthur L. Burnett, nitric oxide “is clearly understood to have major importance in mediating penile erections.”  Nitric oxide is ultimately an “effector of corporeal smooth muscle relaxation,” which allows an erection to occur.  However, the Knowles et al. study showed that “oral administration of l-arginine in high doses seems to cause significant subjective improvement in sexual function in men with organic [erectile dysfunction] only if they have decreased [nitric oxide] excretion or production,” meaning that men who have normal levels of nitric oxide production will not be affected by the l-arginine in Enzyte.  This study also showed that “the haemodynamics of the corpus cavernosum were not affected by oral l-arginine at the dosage used,” meaning that the quality of  erections was not affected by the l-arginine.  Therefore, this component of Enzyte might be ineffective unless the consumer already has erectile dysfunction and low levels of nitric oxide.



If you are considering trying Enzyte, you should talk to your doctor first to see if there would be any health risks or if you even need to use it in the first place.  Because the scientific literature relevant to this topic is very limited and narrowly focused, it is difficult to say whether or not Enzyte would be effective in its concentrations and combinations of herbal ingredients.  It is also difficult to determine if it would be better to just take ginseng or horny goat weed or any other component of the product by itself to save money and avoid any unnecessary chemicals.  Further research is required to say if this product works like it's advertised, but if you really think that you could benefit from it, the scientific evidence supporting some of the ingredients makes it plausible enough to at least get a free trial.






Enzyte: The Once-Daily Tablet for Natural Male Enhancement. Retrieved from


Herbal Supplements: Are They Safe? Retrieved from


Does Enzyte Really Work? (2008). Retrieved from


Does Enzyte Work? (April 9, 2009). Retrieved from


Enzyte by Berkeley Premium Nutraceuticals. Retrieved from


Sexual Function. Retrieved from


Enzyte. Retrieved from


Does Enzyte Really Work? Retrieved from


“Smiling Bob” Not Smiling Anymore. (March 2, 2006). Retrieved from


Enzyte Christmas – Smiling Bob. Retrieved from


Rubin, R. (2002). Why is this man smiling? It's not Viagra. USA Today. Retrieved from


Enzyte Scam and Lawsuit Information. Retrieved from


Enjoy natural male enhancement with Enzyte! Retrieved from


Does Enzyte Work? Retrieved from


Does Enzyte Work? Retrieved from




Adimoelja, A. (2000). Phytochemicals and the breakthrough of traditional herbs in the management of sexual dysfunctions. International Journal of Andrology, 23(2), 82-84.


Kalamegam Gauthaman, Adaikan P. Ganesan, R. N. V. Prasad. The Journal of Alternative and Complementary Medicine. April 2003, 9(2): 257-265.


Yeh, K., Pub, H., Kaphlec, K., Lina, S., Wuc, L., Linc, J., and Tsai, Y. (2008). Ginkgo biloba extract enhances male copulatory behavior and reduces serum prolactin levels in rats. Hormones and Behavior. 53(1), 225-231.


Cohen, A. J. Brief Report: Long Term Safety And Efficacy Of Ginkgo Biloba Extract In The Treatment Of Anti- Depressant-Induced Sexual Dysfunction. Retrieved from


Hong B, Ji YH, Hong JH, Nam KY, Ahn TY. (2002). A double-blind crossover study evaluating the efficacy of korean red ginseng in patients with erectile dysfunction: a preliminary report. J Urol. 168(5), 2070-3


Makarova, M. et al. (2007). Effect of lipid-based suspension of Epimedium koreanum Nakai extract on sexual behavior in rats. Journal of Ethnopharmacology. 114(3), 412-416.


Burnett, A. (1997). Nitric Oxide in the Penis: Physiology and Pathology. Journal of Urology. 157(1), 320-324.


Knowles, R. G., Palacios, M., Palmer, R. M., and Moncada, S. (1989).Formation of nitric oxide from L-arginine in the central nervous system: a transduction mechanism for stimulation of the soluble guanylate cyclase. Proceedings of the National Academy of Sciences of the USA. 86, 5159-5162





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