BUENOS AIRES—The "menu" of options, sent every other week via WhatsApp, arrived like it always did, Josefina (not her real name) recalls. Only this time there was something that caught her eye besides the constantly increasing prices. "Tuci," it said.

Josefina's dealer was offering a new drug, one she'd never heard of before. And at 1,500 Argentine peso (46 euros) per gram, Tuci was the priciest of the lot. Surprised — and also curious — resent the list to a group of WhatsApp contacts. She wanted to see what her friends thought.

"Let's buy it. Come on, let's try it," one of them replied. "It can't be Tuci. It's too cheap," wrote another before adding: "You get 50 doses from one gram. It's nothing considering what the drug's really worth." That was the specialist opinion.

Tuci may be a new option in Argentina, but not elsewhere. In Europe it's known as the "cocaine of the rich," used by stars, models and politicians, according to a 2012 report in the Colombian weekly Semana. In other countries the drug goes by the name 2C-B. It is a synthetic version of a mind-altering substance developed in the United States in 1974. Its developer, Alexander Shulgin, called it pink cocaine.

In Argentina, it is consumed discreetly, and in exclusive circles. As far as Clarín could gather by taking to users, Tuci arrived about five or six years ago. It was initially linked to Colombian criminal elements, and consumed at electronic music clubs in the districts of Palermo and waterfront areas. People who were high on the drug caught the attention of other club goers, who wanted to try it themselves. If the interested person was a regular on the nightclub circuit and trusted, a meeting was arranged the following week.

At that time a gram cost 1,000 pesos (31 euros), about three-and-a-half times the cost of standard cocaine. Today it goes for twice that, making it the most expensive drug on the market. Normally it's bought outside discotheques. Last January, Government Decree 722/1991 included it on the list of the country's illegal substances. So far, though, police forces have reported just one pink cocaine bust — nearly three years ago, in Quiaca, Jujuy.

In Buenos Aires, Tuci is snorted, while in Colombia and Europe it is taken orally.

The word Tuci is short for tucibi (a phonetic spelling of 2C-B), which is also the alias (Alejandro Tucibí) of a drug pin known in Colombia as the "Pablo Escobar of synthetic drugs." He is said to have traveled to Europe in the decade after 2000, attracted by its electronic music bashes, and supposedly met two chemists there who introduced him to a drug they made for Colombians and the rich. He returned to Medellín with the recipe and began producing and selling the drug at electronic music parties.

The business spread to Cali and Bogota, and in time provoked a war between cartels seeking its formula. According to Semana, one of the crimes related to the fight over 2C-B was the 2012 killing, in Buenos Aires, of the Colombian paramilitary and drug-gang assassin Jairo Saldarriaga.

Tuci is reputedly under Colombian control in Buenos Aires. The drug is thought to arrive from Cali in western Colombia. But a Colombian NGO, Échele Cabeza, thinks the substance sold here is something else, that it may not really be 2C-B. "In 95% of cases they're fakes, adulterated substances, replacements and mixes of mind-turning substances that are very dangerous," the group told Clarín. "Most likely the mix includes Sildenafil (viagra) to increase stimulation. But that as raises the risk of tachycardia and heart attacks."

Tomás Pérez Ponisio, a member of PAF!, a civil association that works on drug-related social problems, says he used Tuci just once, at a party in Mar del Plata. He was offered it twice more. "It must be available... because you can get anything in Argentina. But it's not widespread like other drugs. We have had very few experiences reported to our webpage, and considering how they tell us they consumed it and the price paid for it, it wouldn't be 2C-B."

In Buenos Aires, Tuci is snorted, while in Colombia and Europe it is taken orally. The doses also vary greatly. In Argentina users buy it by the gram, which in other countries can last for various nights or be shared among a group.

"It is a drug to be taken in small doses," says Carolina Ahumada of PAF! "We're not used to that in Argentina." She says that taking it like cocaine or other drugs could be a problem. "There is a lack of information," she adds. "People don't know how to take it. In any case the Tuci we find in Argentina seems to be at a knock-down price."

A Colombian drug dealer currently jailed in Buenos Aires agreed to talk to Clarín. He admits he took Tuci in Bogota and says he found out about its arrival in Argentina while in jail. "Selling Tuci in Argentina is not good business for Colombians," he said. "Those who do it make us bring more than two kilograms per trip. Colombian drug dealers have never worked in small time dealing. This is only worth it if they stretch the drug with other products. There are people from my country who allow themselves the luxury of ordering some for their personal use, or ask relatives or friends traveling here to bring the odd 10 or 20 grams. Just to enjoy the "the original.""