Procedures range from manual exercises to stretching devices and surgical procedures, with reports of successes and failures around the world. While some of these are known to be outright hoaxes, other techniques seem to have some measure of success.

Very little legitimate scientific research has been done on penile enlargement, so any claims of significant and permanent enlargement can be biased or anecdotal. Conversely, there is an element of risk to most all of the procedures, with negative outcomes ranging from the tearing of skin and scarring, to permanent loss of sexual function. Due to the speculative nature of any hope for "improvement" and the many known cases of permanent injury involved in this endeavor, many medical professionals are skeptical of the subject.

At present there is no consensus in the scientific community of any non-surgical technique that permanently increases either the thickness or length of the erect penis that already falls into the normal range (4.5" to 7").

Surgical techniques used for penis lengthening (enhancement phalloplasty) and penis widening (girth enhancement) have been in the urologic literature for many years. In a study conducted at St. Peter's Andrology Centre and Institute of Urology in London, it was determined that most patients who underwent penis-lengthening surgery were unsatisfied with the results. (September 2006).

Approximately one-third to one-half of the penis is inside the body, and is internally attached to the undersurface of the pubic bone. Penis lengthening involves the release of the fundiform ligament and the suspensory ligament that attaches the two erectile bodies to the pubic bone (ligamentolysis). The suspensory ligament makes the penis arch under the pubic bone. Release of this ligament allows the penis to protrude on a straighter path, further outward to give a longer physical appearance. With the penis on stretch, the ligament is divided close to the pubic bone until all midline attachments have been freed. Once these ligaments have been cut, part of the penile shaft (usually held within the body) drops forward and extends out, enlarging the penis by 2–3 cm (0.78–1.18 in.). After surgery, part of the postoperative treatment includes stretching of the penis to prevent the severed suspensory ligament from healing shorter than it was previously. The article "Penile Suspensory Ligament Division for Penile Augmentation: Indications and Results" discussed the subject. According to Nim Christopher, a urologist at St. Peter's Andrology Center in London, among men who have had the surgery, "the dissatisfaction rate was in excess of 70 percent".

Real penile lengthening (i.e., lengthening of corporal bodies vs. ligamentolysis) is not a routine or safe procedure because of high risk of losing the ability to have an erection. It can only safely be done during implantation of penile prostheses in patients with erectile dysfunction or Peyronie's disease[citation needed]. The world's leading urologists specializing in the field of penis enlargement surgery use only ligamentolysis, liposuction of the pubic area, and skin redistribution. They state clearly that surgeons can only expose the penis more outside the body with especially visible results in obese patients and ones with different deformities of penile skin where the penis is layered.

A further method is to replace the two corpora cavernosa with inflatable penile implants. This is performed primarily as a therapeutic surgery for men suffering from complete impotence; an implanted pump in the groin or scrotum can be manipulated by hand to fill these cylinders from an implanted reservoir in order to achieve an erection. The replacement cylinders are normally sized to be direct replacements for the corpus cavernosa, but larger ones can be implanted.

One advantage to this surgery is that an erection can be created whenever desired, for as long as is desired and as firm as desired. However, this surgical procedure can never be reversed.

Rather than attempt to change the actual size of the penis, one may make it appear bigger, by trimming the pubic hair or by losing weight.

"Penis enlargement pills", "penis patches" or ointments are commonly offered over the Internet. This is one of the most common topics for spam email messages. Analyses performed by Flora Research of California and by the University of Maryland have uncovered harmful contaminants in a number of "penis enlargement" pills. Contaminants found included mold, yeast, dangerous E. coli bacteria, pesticides, and lead. Dr. Michael Donnenberg of the University of Maryland has described herbal pills marketed as having "heavy fecal contamination", possibly from animals grazing near the plants harvested for herbal ingredients.