A 40-year-old scientist backed by Boris Yeltsin, Mr Sadykov is the master alchemist of 'red mercury', a substance one British nuclear expert believes can produce a nuclear bomb no heavier - and smaller - than a watermelon. Others consider it a hoax, a cover for money laundering or plutonium contraband.
'Red Mercury makes it possible to do things only charlatans could pretend to do before,' boasts Mr Sadykov, whose private firm, Promekologia, was given exclusive rights last year by Mr Yeltsin to produce, buy and sell stuff his security ministry calls a phantom.
Reported applications of the cherry-red gel range from nuclear bombs to bewitching perfumes. It is also sold as an ingredient in anti-radar coating, self-targeting warheads and oil- well anti-coagulants.
With a nuclear archipelago comprising 189 separate facilities, Russia spawns countless scams and scares - eg, the 'elipton', the secret and, the military says, non-existent weapon Vladimir Zhirinovsky wants to give Bosnia's Serbs, and the 'atomic pistol' he threatened France with earlier this month.
Red mercury keeps better company. 'I'm pretty well convinced it exists,' says Dr Frank Barnaby, a former scientist at Aldermaston, Britain's nuclear weapons laboratory. 'It's an enormous conspiracy, if all the people I have spoken to are lying.' Most bomb makers are more sceptical. 'This is the unicorn of modern science,' says Vic Hogsett, analyst at America's nuclear research centre, Los Alamos. 'You can put your hand on a Kalashnikov, you can touch plutonium. With red mercury there just doesn't seem to be anything there.'
But there is enough smoke, and at least one body - a Briton left smeared with a black slime containing mercury - to suggest some sort of fire.
How or where Mr Sadykov found red mercury he won't say. All the same, he convinced a Californian company, API International, to sign a contract for dollars 24bn ( pounds 16bn) for 84 tons of the miracle gel. He claims a string of other deals, too. 'I'm already a millionaire. In 10 years I'll be a zillionaire.'
There is little sign of any such prosperity at Promekologia's headquarters, a row of spartan offices off a dingy ninth-floor hallway. They are modest premises for the premier trader of a product priced at dollars 300 a gram - 22 times more expensive than gold.
Many rooms are empty. Alexander Popov, a chemical engineer, sits at a rickety wooden table and explains why few people have seen red mercury: 'As we used to say in the Soviet Union, the less you know the better.' The entrance to Promekologia has a heavy steel door; other doors are welded shut; gruff security guards impersonate James Bond villains.
Mr Sadykov, who also has a scruffy office in Moscow, declines to provide samples of his product: 'We tell everyone, 'You want to see it? Buy it.' '
Numerous sightings of the substance have been reported. Touts have been arrested in Sweden, Finland, Italy, Germany, Switzerland and Bulgaria. A Czech journalist says he brought some in Vladivostok. Russian police say they arrested Kazakh smugglers in Omsk with a five-kilo consignment.
The most gruesome episode occurred in South Africa, where the sales director for Thor Chemicals was found stuffed into the boot of a BMW, his dismembered body daubed with a thick, black substance.
'The legend goes back a long way,' says Dr Hogsett. 'Run each story to ground and you end up with the same thing - nothing. Call it Red Mercury, call it a Big Mac, whatever you want. I call it a scam.' A security ministry report to Russia's parliament said red mercury was underworld jargon, 'like the word cabbage for money'.
But Mr Sadykov's deal with API in California is real, as is the order signed by Mr Yeltsin. Mr Sadykov shows off a signed contract and a photocopy of the Kremlin decree; and he has a letter from the San Fernando Valley Chamber of Commerce that speaks highly of API and its boss, J C Godinez. Here, however, the trail goes cold. The hunt for API's headquarters leads to a garage. The letter of recommendation is disowned by the man who signed it, chamber of commerce vice-president Albert Carreora, who has since retired to a houseboat in the Philippines. He says that he was tricked.
Dr Barnaby says he used to be a sceptic, too. He first heard of red mercury in 1985 after the arrest of a South African smuggler in Greece. What changed his mind was a recent trip to Russia for a Channel 4 documentary. 'Even if 95 reports out of 100 are fraudulent, there is a residue that is not.'
In red mercury's more lethal form as a trigger for nuclear reactions, it is said to be an antimony mercury oxide. It starts out as a powder and is synthesised under intense radiation and pressure into a malleable gel. Legend credits the technique to Soviet military researchers in the 1960s, and says it has since been perfected at a laboratory in the Siberian city of Krasnoyarsk.
'Some brilliant minds have come up with a new element in the Mendeleyev table,' former vice-president Alexander Rutskoi told parliament last year. 'They are sending abroad this substance which does not exist in nature.' He won an investigation into why Mr Yeltsin had smiled on Promekologia, the presidential order was cancelled and the affair was swamped by the drama of tanks in the streets of Moscow.
When a new constitution last December granted Mr Yeltsin sweeping powers, the public prosecutor dropped his inquiries, and last month he told Tass news agency: 'It has been established that none of the enterprise or research institutes has ever synthesised or made a product with the qualities or characteristics attributed to red mercury.'
Scientists at the Academy of Sciences in Moscow have a collection of so-called 'red mercury' potions. Fakes from around the world range from the worrying (depleted reactor fuel and low-grade uranium) to the laughable (mercury tinged with brick dust and an empty bottle painted with nail polish).
But Promekologia presses on: 'This is a revolution, a triumph. This will be Russia's salvation,' says Mr Sadykov.