It’s good to be hard, and hard to be good …

Propionyl-L-carnitine, arginine, and niacin
can help make you a better man 

The greatest pleasure of life is love. — Euripides

We’ve frequently heard that love is at the core of human existence. However, imagine zeroing in on Earth, having come a very vast distance across space and time. As a creature from a dark solar system, you don’t have eyes in the usual sense. Thus, a principal source of your knowledge about life on the blue-green-white jewel planet—toward which you are heading—is derived from radio programming with its incessant ads for sexual enhancement supplements …

    • Be all the man that you can be
    • Boost testosterone by 50%
    • Go big and strong all night long
    • Increased virility and heighten sexual desire
    • Perform for hours, multiple times
    • Increase male sex hormones levels and stamina
    • Dramatically increase control
    • Increase the size of your penis
    • Have stronger and more intense orgasms
    • Strengthen your erections and enhance libido
    • Before I was a 2; now I’m a 10!
    • Clinically proven and doctor recommended!
    • Works naturally with your body and causes no side effects
    • Effective within 10–30 minutes

Notice that in this list, love is not mentioned even once.

What Do Extraterrestrials Understand About Earthling Men?

Back on the sphere known as Earth, the bombardment doesn’t stop, with a conjoined slogan that proclaims it is now possible for you to unite your libido with your erections, thus self-creating a new type of superman. And everything is science-based, according to the ads. What is an ET to think?

What does sexual activity have to do with health?

Listening to the radio makes it seem that we are far more advanced than seemed possible just a short while ago. Yet, the Niagra Falls-type male sexual function drugs—phosphodiesterase type 5 inhibitors (PDE5i)—which especially target erectile dysfunction (ED), have a long way to go, not to mention a lot of side effects. And many of their counterparts in the nutritional supplement field remain relatively underexplored. What’s the real deal, a terrestrial wants to know? And furthermore, as the doctor endorsement in the bulleted list implies, what does sexual activity have to do with health? And, what about love?

Measuring Sexual Performance

In a group of 54 men (between the ages of 35 and 75) who showed up for treatment at an ED clinic at Sapienza University of Rome—and who hadn’t used any other ED treatments—researchers carried out a single-blind, one-arm study (not a joke) to evaluate the effects of a 3-month supplementation with propionyl-L-carnitine (PLC), L-arginine and niacin on their sexual performance.1

All subjects were given the short-international index of erectile function (IIEF) questionnaire, at startup and 3 months afterward. Consisting of 6-items—questions 1–5 and 15—IIEF hones in on the frequency of erections during intercourse (q1), whether the erections sufficed for penetration (q2), whether intercourse was attempted and successful (q3), whether erections were maintained after penetration (q4), whether erections were maintained to completion of intercourse (q5), and how each subject rated his confidence that he could get and keep his erection (q15).

Also measured were global assessment questions (GAQs) and routine laboratory testing. Of the 54 subjects who began the study, 50 completed. Following 3 months of treatment, a statistically significant improvement in total and single items of the IIEF was found.

Beyond Penile Rigidity

Analyses on the GAQs revealed that treatment clearly improved erections in 40% of cases, with partial response occurring in up to 77% of the subjects. These preliminary findings indicate that the favorable cardiovascular effects of supplements might partially explain enhanced male sexual function, and accordingly be useful for both the treatment and prevention of ED. What is especially interesting is that this study demonstrated considerable interest by the subjects toward nutritional supplementation—as a first-line or adjunctive treatment to PDE5i’s—that goes beyond the measurable increment in penile rigidity.

Sex and Health

ED is acknowledged as a widespread health problem. It is associated with atherosclerosis, and its prevalence is higher in patients with diabetes, metabolic syndrome, dyslipidemia, obesity, and among those who smoke and exhibit sedentary behavior. Altogether, these conditions also represent risk factors for myocardial ischemia (restricted blood flow to the heart).

While the quality of life of those with diabetes and ED has been dramatically improved by PDE5i treatments, the benefit is largely because of their effectiveness as symptomatic agents. It is not because they slowdown, abolish, or reverse the underlying causes of ED.

The effects of PDE5i’s have only been reproduced in clinical trial settings and seldom achieved in real-life situations. This may be, according to the researchers, due to the unaffordable cost of such regimen schemes or, more likely, due to the persistence and progression of the same risk factors that caused ED, i.e. diabetes, hypertension and atherosclerosis. For this reason, there is a desperate need of etiological treatments that identify the causes, treat the underlying diseases, and also are proven to be effective in symptomatic relieve of ED. Nutritional supplements may be able to provide such a balance, where drugs have failed.

The Biology of an Erection

An erection occurs when the smooth muscle cells of the penile arteries relax, allowing an increased, rapid flow of blood into the penis. This causes it to enlarge and become tumescent. Imagine an inflated balloon: filled with air, it’s turgid and stiff. When the amount of air is reduced, the balloon becomes limp, or flaccid.

The erectile process is under strict biological control, generally occurring—during waking hours—only in response to a sexual stimulus. But what is the signal that starts the entire mechanism? With sexual excitement, the natural process by which the body’s amino acid L-arginine undergoes a chemical reaction that releases nitric oxide (NO) is accelerated, setting a complex chain of events into motion. Nitric oxide stimulates guanylyl cyclase, a protein, to produce cyclic guanosine monophosphate (cGMP), a small molecule present in the smooth muscle cells. cGMP induces relaxation of the cells, allowing an inflow of blood to the corpus cavernosum, the spongy tissue of the penis. Engorged with blood, the tissue stiffens and produces an erection.

Have you ever wondered why erections don’t last long? In part, they’re time-limited because smooth muscle cells possess a protein called phosphodiesterase (PDE), which steadily breaks down cGMP, making it inactive. When cGMP levels fall, the muscle cells lose their relaxation and can no longer accommodate the abundant blood flow necessary for erection. As a result, blood recedes from the tissue, and flaccidity ensues. Interestingly, many men have fairly active PDE levels in the corpus cavernosum. This is bad news if achieving an erection is your goal, because the smooth muscle cells can’t relax, thereby short-circuiting the erectile process. As PDE5i’s, Niagra-type drugs counteract PDE function, elevating cGMP levels, which results in smooth muscle cell relaxation, and—voila! An erection.

L-Arginine Boosts Erectability

So now you can understand why the NO-cGMP pathway is the target of the most widely used pro-erectile drugs. But these drugs do not increase NO. L-arginine, the precursor amino acid from which NO is generated, can enhance activation of this pathway thus facilitating erections. In a double-blind placebo-controlled study, testing L-arginine versus placebo in men with ED, subjective improvement was reported by 31% of men taking L-arginine as compared to 12% of men taking placebo.2 Hence, as a single intervention, L-arginine is effective, doubling the placebo effect. Yet, it is not sufficient to be considered as a single line of intervention of the symptomatic treatment of ED, at least if one is not already healthy. But on clinical grounds, L-arginine supplementation was able to lessen the endothelial dysfunction associated with hyper­cholesterolemia and coronary heart disease3 and prevent hypertension induced by sodium chloride loading.4

In humans, the administration of L-arginine significantly lowered blood pressure in salt-sensitive hypertensive individuals,5 as well as normotensives.6 Also, it has been found that the NO-cGMP pathway is impaired in diabetic men, when endothelial dysfunction is caused by oxidative stress.7 This type of dysfunction may diminish the response to even the best of the PDE5i drugs, which once again are not without side effects, some quite serious.

Dietary supplementation is associated 
with a lower anxiety of possible 
additional adverse effects.

Nevertheless, the researchers of the Sapienza University of Rome study concur that PDE5i nonresponders may be able to respond to PDE5i’s when combined with antioxidant therapy that improves cardiovascular function, such as PLC. Such a combination constitutes symptomatic relieve of ED accompanied by a curative treatment of the endothelial dysfunction that caused impotence.

Propionyl-L-Carnitine Improves Cardiovascular Disease and ED

Recently, additional studies confirmed the value of the therapeutic association of carnitines such as PLC and PDE5i.8 PLC is a naturally occurring derivative of carnitine that plays an important role in the metabolism of both carbohydrates and lipids, leading to an increase of ATP (the universal energy coenzyme) generation. PLC, however, is not only a metabolic supplement; it is also a potent antiradical agent and thus protects tissues from oxidative damage.

An emerging thought is that all cardiovascular disease patients may benefit from carnitine use, given that these diseases are highly associated with ED. Indeed, they often share its pathophysiologic mechanisms.

Lastly, in atherosclerosis, coronary, carotid and peri­pheral arterial diseases frequently coexist. Curiously, in atherosclerosis, while low-density lipoprotein cholesterol (LDL-C) reduction with statins has consistently shown reduction in major cardiovascular events and mortality, treatment of LDL-C with statins prevents only a small number of cardiovascular events. Furthermore, epidemiological studies have shown a strong inverse relationship between coronary heart disease risk and high-density lipoprotein cholesterol (HDL-C), independent of high or low levels of LDL-C.9 This relationship persists in patients who have been treated with statins, providing a rationale for additional or even replacement approaches to improve HDL levels.

Niacin Improves Cardiovascular Disease and ED

Nicotinic acid (aka niacin) has been shown to raise HDL-C by approximately 20% to 25% and is the most effective clinically available supplement or drug for HDL-C elevation, besting even statins.10 Once again, there is strong epidemiologic evidence linking the risk of ED to a variety of diseases, including coronary heart disease, metabolic disorders and endothelial dysfunction. This emphasizes the separation of the symptomatic treatment for ED and treatment of the underlying diseases. Consequently, the nutritional supplement approach is needed, adjunctively at the very least. Because of its duality, in the long run it may prove to be the key solution. It is interesting to note that ED patients often are taking many other medications, which are likely to produce drug interactions. Favorably, dietary supplementation is associated with lower anxiety, resulting from reduced additional adverse effects. In the present report, the researchers have documented that the association of supplement interventions consisting of PLC, niacin, and L-arginine has measurable effects on erectile function and sexual life satisfaction. They may even provide first-line treatment in selected patients, and obviate the need for PDE5is.

The Evolving ET Viewpoint

Back to our imagination again: Once the space-traveling extraterrestrial lands on Earth, the radio ad distortions dissipate as direct communication takes place. Then, in the mind of the ET, Earthmen are not merely pawns of their physiological drives. They are seekers of health—of which sexuality is a proof—and even desirous of love, as perhaps an all-encompassing pleasure. That’s hopeful.

Heart Rate Variability Strengthened by Orgasms

At the School of Social Sciences, University of the West of Scotland, Paisley, UK researchers have found that resting heart rate variability (HRV)—a marker of parasympathetic activity—is a predictor of health and longevity.1 Better erectile function is associated with greater resting HRV, and in both sexes, penile-vaginal intercourse (PVI) is the only sexual behavior consistently associated with indices of better physical and mental health, including greater resting HRV. After all, this is Scotland.

The hypotheses of the researchers was that greater frequency of orgasms attained through PVI—for women without additional simultaneous clitoral stimulation—are associated with greater resting HRV. Countering that hypothesis is the idea that HRV measures might be unrelated to orgasmic frequency from noncoital sexual activities.

One hundred forty-three coitally experienced men and women had their heart rate measured for 5 minutes and reported the frequency of various sexual behaviors and corresponding orgasms in a recent representative month. Using partial correlations and covariance controlling—in probability theory and statistics, covariance is a measure of how much two variables change together—analyses for social desirability responding were used to examine the associations of sexual activities with time and frequency domains of HRV.

In the men, greater resting standard deviation of heart rate was associated with greater PVI orgasm frequency. For women, the same measure of heart rate was associated with any vaginal orgasm. These findings remained after controlling for cohabitation.

Lifetime number of PVI partners was unrelated to resting standard deviation of heart rate (assessed by high frequency power).

Under discussion: That orgasms achieved through PVI enhance HRV, and greater parasympathetic tone favoring the capacity to engage in PVI, and in the case of women, to reach vaginal orgasm. The possibility of healthier people having greater resting HRV and more frequent orgasms specifically through PVI was also considered.


  1. Costa RM, Brody S. Greater resting heart rate variability is associated with orgasms through penile-vaginal intercourse, but not with orgasms from other sources. J Sex Med 2011 Nov 14. doi: 10.1111/j.1743-6109.2011.02541.x. [Epub ahead of print]


  1. Gianfrilli D, Lauretta R, Di Dato C, Graziadio C, Pozza C, De Larichaudy J, Giannetta E, Isidori AM, Lenzi A.Propionyl-L-carnitine, L-arginine and niacin in sexual medicine: a nutraceutical approach for erectile dysfunction. Andrologia2011 Oct 4. doi: 10.1111/j.1439-0272.2011.01234.x. [Epub ahead of print]
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