The internet is awash with websites selling everything from pills to penis extenders that claim to increase the length and girth of your manhood. But do these treatments work?
Men's anxiety about penis size has spawned a multi-million-pound global industry in clinically unproven "male enhancement products".
While many men worry their penis is too small, research shows that most men's penises are normal and they needn't be concerned. Professor Kevan Wylie, a sexual medicine consultant, says men with concerns about their penis size should consider talking to a health professional before experimenting with treatments, which are mostly ineffective, expensive and potentially harmful.
"Many men who worry about the size of their penis generally have overall body image issues," he says. "What happens is that they tend to focus their poor body image on their penis.
"Often, counselling can make a real difference to the patient by building self-esteem, correcting distorted views about body image and learning more about what makes people attractive."
Professor Wylie assesses the evidence, effectiveness and safety of different types of penis enlargement products and treatments on the market.
Pills and lotions
These products usually contain vitamins, minerals, herbs or hormones that claim to enlarge the penis. Despite their impressive claims, there's absolutely no clinical evidence that these products work and some may even be harmful. The University of Maryland in the US carried out an analysis on some of these and found traces of lead, pesticides, E. coli bacteria and animal faeces.
"They're a complete waste of time," says Professor Wylie. "Pills and lotions have no proven benefit. If they were effective, they would be on sale at chemists. Using a lotion may help a man become more familiar with his penis, which some men shy away from. So lotions can help a man become more comfortable with his penis but they certainly won't make it any bigger."
Penis pumps involve placing a tube over the penis and then pumping out the air to create a vacuum. The vacuum draws blood into the penis and makes it swell. Vacuum devices are sometimes used in the short-term treatment of impotence. But overusing a penis pump can damage the tissue of the penis, leading to weaker erections.
"There is very little evidence that these devices cause any significant long-term gain in size," says Professor Wylie. "Using a pump for a few minutes a day won't do anything to increase penis size."
This technique involves placing a weight or a small extending frame, sometimes called a traction device, on the flaccid penis to stretch it. Professor Wylie says there is no clinical evidence that using weights will extend the penis, and they may cause permanent damage to the penis. However, better results have been reported with traction devices.
"There is some evidence that traction devices can have some impact, particularly with men who are smaller in size," he says. "Some patients using traction devices for six months have noticed a gain in size of 1-2cm. However, such treatments should not be started without the supervision of a doctor."
Jelqing is an exercise involving repeatedly pulling the flaccid penis using the thumb and index finger, with the aim of increasing erection size. The idea is that the pulling exercises will increase the blood capacity of the penis' erectile tissue, allegedly resulting in increased length and girth of the penis.
"Just like using lotions, this technique can help some men better appreciate the considerable difference in size between a flaccid penis and an erect one, which helps them become more comfortable with their body," says Professor Wylie. "But there is no scientific evidence to suggest jelqing can increase penis size."
Penis girth surgery
Some surgical techniques to increase penis girth involve injecting fat taken from another part of the body into the penis. Some studies have reported increases in circumference of 1.4-4cm. However, studies that followed men up over a longer time suggest disappointing results, with complications including disfigurement, scarring, lumpiness and infection. Another method, still in its experimental stage, involves pulling back the skin of the penis to wrap a tube-like biodegradable frame filled with tissue cells around the shaft.
Professor Wylie says the use of biodegradable frames has had better results than fat injection. "The problem with injecting fat is that over time, the body will re-absorb the fat which can result in a return to the penis' original size," he says.
Penis length surgery
The most common technique involves cutting the ligament that attaches the penis to the pubic bone and performing a skin graft at the base of the penis to allow for the extra length. Professor Wylie says the surgery can result in an average gain in length to the flaccid penis of 2cm, but there will be no change to the size of the erect penis. Furthermore, the erect penis won't point as high as before the operation because the ligament which was cut no longer offers support.
"A lot of men who have this treatment don't truly appreciate this loss of angle," says Professor Wylie. "It can make sex quite uncomfortable. You've got to do a lot more manoeuvring with your partner. The advantage of a 2cm gain in flaccid length is far outweighed by the loss of angle of erection."
As penis enlargement surgery is for cosmetic purposes, it's unlikely to be available on the NHS.
For men with a large gut, liposuction, a surgical procedure to remove fat below the abdomen, can make their penis look larger. Removing excess fat around the pubic area can make a partly buried penis appear more prominent.
Professor Wylie says the cosmetic results are generally considered reasonable by patients. "Liposuction can result in a 2cm gain in length in the short-term, but the fat will return to the pubic area if the patient puts on weight again," he says.
"The procedure can give the patient a confidence boost, but for it to be sustained over the long term, they need to improve their diet and get exercising."
However, like all surgical procedures, liposuction carries the risk of side effects and complications. Find out more about the risks of liposuction.