PropeL and Prostate Cancer

Q. Dear Dr. Dean,

I have prostate cancer. Is it OK to take PropeL? Have there been any studies to this end? I know the conventional medical industry does not recommend testosterone based products if you have prostate cancer. I want to increase my energy and enhance my sex life. I look forward to your reply.

ROB, Maroochydore QLD, Australia

A. Dear Rob,

The short answer, is: Yes, you can safely take PropeL, despite your having prostate cancer.

As you imply, conventional medicine discourages the use of testosterone for those diagnosed with or at risk for prostate cancer. For decades, the medical establishment erroneously (I believe) conjectured that testosterone replacement therapy increased one’s risk of prostate cancer. In a recent book, Testosterone for Life, by Harvard-based urologist Abraham Morgentaler, M.D., FACS, Dr. Morgentaler convincingly demonstrates this theory to be mistaken. Contrary to the notion that restoring testosterone to youthful levels is somehow risky, Dr. Morgentaler meticulously shows that those with low testosterone (and often, high estrogen) are the ones at risk for prostate cancer.

That being said, the ingredients in PropeL—principally, acetyl-L-carnitine (ALC), propionyl-L-carnitine (PLC), and alpha-lipoic acid (ALA)—do not affect testosterone levels, but act by different mechanisms. Both acetyl-L-carnitine (ALC) and propionyl-L-carnitine (PLC) are natural substances that boost our energy by acting as sources of their parent compound, carnitine, an amino acid. Carnitine facilitates the transport of fatty acid molecules across the mitochondrial membranes. Without these fuel molecules, our mitochondria (the cells’ chemical “powerhouses”) would cease functioning—and so would we. Carnitine levels tend to decline with age, so maintaining a healthy supply of this compound is a good idea.

For energy metabolism, ALC is more important than PLC, because ALC acts as a delivery system for both carnitine molecules and acetyl groups.

ALC improves memory and other cognitive functions in people with mild cognitive impairment and early Alzheimer’s disease, exerts a neuroprotective effect, thereby inhibiting the peripheral neuropathy that often accompany diabetes, and ALC helps to prevent age-related glycation, which degrades the proteins in our eyes’ lenses.

Cardioprotective properties have been attributed to ALC, and to PLC as well. PLC, in particular, may be helpful in treating such cardiovascular disorders as congestive heart failure, angina pectoris, and intermittent claudication (pain upon walking, owing to peripheral arterial disease).

ALC and PLC tend to have an indirect pro-oxidant effect because of their enhancement of cellular energy metabolism, the primary source of free radicals in our bodies. This tendency can be offset, however, by the potent antioxidant lipoic acid, which should therefore always be taken along with ALC and PLC. [See “Can Acetyl L-Carnitine and Lipoic Acid Slow the Aging Process?” (October 2004).]

To evaluate a combination of ALC and PLC on subjective energy production and revitalization of sexual potency, Italian researchers conducted a double-blind, trial comparing propionyl-L-carnitine and acetyl-L-carnitine versus testosterone undecanoate (a form of oral testosterone that is available in Europe).1 They recruited 150 generally healthy men, aged 60–74 (average 64), whose chief complaints were those typical of older men who feel that they’re “slowing down” in various ways. These symptoms include decreased libido, partial to complete impotence, depressed mood, and a reduced ability to concentrate, as well as irritability and fatigue. All the men had very low serum testosterone levels.

The men were divided into several groups: Group 1 received 160 mg/day of testosterone; and Group 2 received 2 g/day of PLC and 2 g/day of ALC. The men were examined at the beginning of the trial and again at 3 months and 6 months, after which the treatments were halted; the final examination was performed 6 months later. A number of variables were measured, including Total PSA, Nocturnal penile tumescence (NPT), and Total and Free Testosterone.

Both groups showed similar, significant increases in the Nocturnal Penile Tumescence at 3 months, and these improvements were maintained at 6 months. After 6 more months without treatment, however, the NPT had reverted to baseline values in both groups. Although the pattern between groups was similar, the PLC/ALC group had significantly better results: whereas the total duration of NPT increased by 48% in the testosterone group, it increased by 88% in the PLC/ALC group!

As expected, testosterone treatment increased both total and free testosterone levels in Group 1. In Group 2, by contrast, treatment with PLC/ALC produced no changes in any of the hormone levels—meaning no undesirable consequences from any such changes.

PLC/ALC Outperforms Testosterone

The researchers also evaluated the men’s sexual function, using the International Index of Erectile Function (IIEF), a standardized set of questionnaires in five categories. The categories and the results observed were:

  1. Erectile function – Both testosterone and PLC/ALC produced significant improvement at 3 months, with further improvement at 6 months. The improvement with PLC/ALC was significantly better than that with testosterone at both time points.

  2. Satisfaction with sexual intercourse – With both treatments, there was significant improvement at 6 months.

  3. Orgasm – There was no improvement with testosterone, but PLC/ALC produced significant improvement at 3 months, with further improvement at 6 months.

  4. Sexual desire – Both treatments produced significant improvement at 3 months, but no further improvement at 6 months.

  5. General sexual well-being – There was no improvement with testosterone, but PLC/ALC produced significant improvement at 3 months, with no further improvement at 6 months.

Depression and Fatigue Are Both Improved

The researchers also evaluated the men’s mood, using a standardized test called the Hamilton Depression and Melancholia Scale. Both treatment regimens produced significant mood improvement at 3 months, with no further improvement at 6 months. At both time points, the scores for the PLC/ALC group were significantly lower—meaning better mood—than those for the testosterone group.

Finally, the researchers also measured the men’s fatigue level, again using a standardized test. The fatigue scores dropped significantly—meaning more energy—for both groups at both time points, by roughly the same amounts.

In summary, the combined carnitine derivatives, PLC and ALC, produced improvements in virtually all the measures used in this study, and greater improvements than testosterone in nocturnal penile tumescence, in three of the five measures of erectile function (per the IIEF questionnaires), and in mood—all without altering hormonal ­levels.

PLC/ALC Enhances Benefits of Sildenafil

The prosexual benefits of PLC and ALC are further supported by the results of another recent study by the same research group, this one on 96 men (average age 61) who had undergone a prostatectomy.2 Many men experience post-prostatectomy erectile difficulties and find help in products such as Viagra (sildenafil). The researchers surmised that PLC and ALC would enhance sildenafil’s efficacy in restoring or improving sexual activity after the operation, and they found that this was true. The men who took PLC/ALC (2 g/day of each) in addition to sildenafil for 4 months had significantly better results in virtually all areas of sexual function than the men who took only sildenafil.

Another Italian research group studied the effects of PLC in combination with sildenafil in 40 diabetic men (average age 64) who suffered from impotence, which is a common consequence of that disease.3 In this 6-month study, the men who took PLC (2 g/day) plus sildenafil (twice weekly) had significantly better results in virtually all respects than the men who took only sildenafil (twice weekly).

So whether the orthodox physicians are right, or “free radicals” like me, and Drs. Jonathan Wright and Abraham Morgentaler are right, you can still take a PLC/ALC product with confidence, as the results that you will obtain are independent of your testosterone levels.

Ward Dean, M.D.


  1. Cavallini G, Caracciolo S, Vitali G, Modenini F, Biagiotti G. Carnitine versus androgen administration in the treatment of sexual dysfunction, depressed mood, and fatigue associated with male aging. Urology 2004;63:641-6.
  2. Cavallini G, Modenini F, Vitali G, Koverech A. Acetyl-L-carnitine plus propionyl-L-carnitine improve efficacy of sildenafil in treatment of erectile dysfunction after bilateral nerve-sparing radical retropubic prostatectomy. Urology 2005;66:1080-5.
  3. Gentile V, Vicini P, Prigiotti G, Koverech A, Di Silverio F. Preliminary observations on the use of propionyl-L-carnitine in combination with sildenafil in patients with erectile dysfunction and diabetes. Curr Med Res Opin. 2004;20:1377-84.

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