And not only by the man who today became the greatest Olympian of all time.
Certainly, Michael Phelps and his five gold medals and five world records in Beijing are a convincing endorsement of the LZR.
But perhaps even stronger proof came from Australia's Eamon Sullivan during today's session at the Water Cube.
Already a multiple record breaker in the Speedo suit, Sullivan saw one of his world marks lowered today by Frenchman Alain Bernard who shaved 4/100ths off the Australian's time in the first semi-final of 100m freestyle.
The setback, however, was extremely temporary.
Before Bernard had dried his hair, Sullivan squeezed another incredible swim out of his LZR-enhanced body and stripped a staggering 0.15 seconds off the new mark in the second semi.
Sullivan seems to have the ability to produce world records at will - he's already delivered two in Beijing and will more than likely find another in tomorrow's 100m final.
But would a young man who has had two hip operations, who has dodgy shoulders and is as thin as a whip swim as fast as he does without the LZR.
The answer is almost certainly "No".
He'd still win, but when he shoehorns himself into an LZR, Sullivan is part Tarzan and part Great White.
The LZR is clearly the biggest development in racing swimsuits since they stopped making them out of wool.
In some quarters, however, they are seen as more than a development.
Opponents have described the LZR Racer as "technological doping".
One of them is Forbes Carlisle, the legendary Australian coach who wrote an open letter to swimming officials demanding they reconsider their decision to approve the suit for the Olympic Games.
Whether the Speedo suit conveys an actual physical advantage or a mere psychological "placebo effect", swimming was being severely damaged, Carlile wrote.
Carlile also hit on another issue of concern.
The Speedo swimsuit is expensive, around $500, and you need a new one after every 10 swims, making it difficult for swimming federations who aren't on the free list, but still want to compete.
The secret of the LZR, according to swimmers, is in the groin and abdomen where the suit has an inflexible girdle-like structure meant to hold a swimmer's body in the best position as they move through the water.
Another benefit is seamlessness. The whole suit is "ultra-sonically welded" together, a technique that bonds plastic using sound waves, thus reducing drag.
It also compresses a swimmer's body, so much so that it often takes 30 minutes or more to put it on.
Zimbabwe's Kristy Coventry says suiting-up is so painful on her fingers that they are constantly wrapped in band-aids "I think everyone is wearing the suit now, so we're on kind of a level playing field," said Coventry, who has set three world records in Beijing and today finished second to Australia's Stephanie Rice in the 200m individual medley.
The Dutch Olympic champion Pieter van den Hoogenband, a veteran of four Games and an LZR convert, welcomed the innovation today.
"It's fantastic ... this is a whole new period of time, a whole new level," he said.
"New swimsuits, a new generation - it's unbelievable." Of the 40 swimming medals awarded thus far in China, 37 of them have gone to athletes wearing the LZR Racer.
Since the suit made its debut in February, it's been used to break 61 world records.
Some swimmers, however, believe there are other reasons, like the deeper pool in Beijing.
Normally an Olympic pool is two metres deep. Here it is three, which reduces turbulence that bounces up from the bottom.
There is also another spin-off from the LZR phenomenon - a clamour to claim a role in the suit's development.
Universities from Otago in New Zealand to Iowa in the United States and Nottingham in England have crowed about their involvement.
NASA has also been given some credit.
Speedo says they are mostly right, although NASA's part was merely to provide a wind tunnel for testing.
The company, which started as a knitting mill in Australia in the early 1900s, brought more than 3,000 suits to the Games and have had queues of more than 100 swimmers at a time keen to be fitted out.
The public has its chance to do the same when the LZR Racer goes on sale after the Beijing Games, but even the makers aren't expecting it to overtake their famous budgie smugglers.
