As an author on sexual enhancement, I am often asked whether penis enlargement is for real. And many readers who send feedback already suggest an answer: it's a hoax.

The surprising news is: it's not a hoax. Penis enlargement is for real.

Look at it from an anatomical perspective. Erectile tissue is extremely flexible. It can be enlarged to about triple its size within less than a minute, when an erection occurs. The erectile tissue of the penis, the corpora cavernosa and the corpus spongiosum, consist of cells with flexible membranes; these cells fill with blood in the event of an erection.

The trick in any sensible penis enlargement program is to stretch these cell membranes in a manner that is of a more lasting nature than the stretching that occurs during an erection.

Also, as the membranes of penile tissue cells are highly flexible, the aim in enlargement programs is to expand the maximum stretching capacity of penile tissue cells. Such programs then result in a larger penis (both longer and larger in circumference) in the flaccid as well as the erect state.

Think of the membranes of erectile tissue cells as being made of a special kind of rubber. The technical specifications for this kind of rubber would be that it is elastic to about three times its non-inflated size. The rubber will usually retract to its original size. However, if regularly flexed to its limits, the retraction will become less than 100 percent (enlargement in the flaccid state).

For industrial rubber, these effects would be the effects of wear and tear. And indeed, people who aim to increase penis size through penis exercise programs as they are sold on the Internet, too, risk factors of wear and tear, such as reduced erectile capability. (I think this is a high price to pay for a penis that looks larger in the flaccid state.)

Penile tissue growth (without wear and tear) depends largely on the testosterone-producing Leydig cells in the testicles. Athletes that use anabolic steroids (exogenous synthetic testosterone) shut down the activities of the Leydig cells in their testicles.

I do think that this is not sufficiently emphasized by anti-doping campaigns: athletes who dope with testosterone and anabolic steroids will cause their penises to become as small as their thumbs or little fingers, and unfortunately, if exogenous testosterone or anabolic steroids are taken for some time, the loss in size can be permanent.

On the other hand, tongkat ali stimulates the Leydig cells to produce more testosterone than they otherwise wood. Because tongkat ali stimulates the body's own testosterone production in the Leydig cells of the testicles, the testicles and surrounding tissue will grow in size. (During puberty, it's a spur in Leydig cell activity, which causes a boy's sexual organs to become the size of a man's. Furthermore, testosterone over-production endocrine disorders during adolescence cause oversized male genitalia.)

However, most of the tongkat ali sold in the US is grossly underdosed and will have little effect in any of the above-mentioned three departments.

While a large number of men may consider increased penile and testicular size a benefit in its own right, the mass gain also influences sexual function, especially erections and ejaculations. The erectile and ejaculatory support of tongkat ali is, so it appears, a direct consequence of the increased size of male accessory sexual structures.

Critical organs in ejaculations, as well as erection firmness, are the levator ani muscles of the pelvic floor. These muscles can be trained through Kegel exercises (an essential part of commercial penis enlargement programs), which, however, are very time-consuming for limited results. It has been shown in a scientific study that tongkat ali can cause a substantial increase in the size of these muscles in particular (an off-shot of the increased activity of testicular Leydig cells).

The following is a link to a scientific article published in the Archives of Pharmacological Research in October 2001.

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve &db=pubmed&dopt=Abstract&list_uids=11693547

Please note that the scientific name of tongkat ali is Eurycoma longifolia jack.

I do want to emphasize three findings of the study that can be accessed through the above link:

1. the statistic size increase of the levator ani muscles was "significant".

2. the dosages used were 200, 400, or 800 mg of extract per kg of body weight; this means that for a man of 80 kg, the equivalent dosage would be 16, 32, or 64 gram of extract per day.

3. the tongkat ali extract was used for a full 12 weeks (3 months) without interruption.

Even for the lowest dosage used in the above-cited animal model (200 mg per day per kg of body weight, or 16 gram of extract per day for an adult man), a full bottle of most commercial tongkat ali extracts wouldn't even provide enough for a single dosage.

Because tongkat ali isn't exactly a cheap herbal (as it is harvested in remote jungles), under-dosing is very common for the producers and distributors of commercial tongkat ali products.

Traditional usage in Indonesia is about 50 gram of root, boiled for half an hour. This would be equivalent to 1 gram of 1: 50 extract.

The lowest dose used in the above study was 200 mg of extract per kg of body weight, which would mean 16 gram of extract per day for a 80-kg man. Assuming a 1:50 extract, this would translate into 800 gram of root in a single dosage.