"Lab analysis of the product known as 'Neo-Viagra' . . . did detect the presence of sildenafil," said Yasar Yaman, Asia-Pacific director for Pfizer's global security team. "Sildenafil is the active ingredient in Viagra, however this is a different formulation to the sildenafil found in authentic Pfizer tablets."
Pfizer couldn't say whether the medicine would work or if it was safe because it had not conducted any clinical trials, and the reporter was not successful in convincing any male acquaintances to try it.
But the fact that Neo-Viagra, made by the state-owned Korea Oriental Instant Medicinal Centre, is being marketed as an "herbal medicine" when it contains the synthetic drug sildenafil, "poses a threat to patient health and safety," Yaman said.
After testing the medicine, Pfizer said it was "currently reviewing" whether to take any action against the North Korean manufacturers for patent or copyright infringement.
Neo-Viagra is sold in North Korea and surrounding areas - it has been spotted for sale in northeastern China - for between US$12 and US$15 for a box of three vials.
The box, which features a photo of trees around a lake, claims to "immediately revive sexual ability (15 to 30 minutes)" for men and women. It also claims to be effective for back, shoulder and knee pain; relieving paralysis; and alleviating "kidney malfunction, sciatic neuralgia, high blood pressure and brain artery hardening".
"This product has been officially recognised in many countries for its excellent effect in immediately increasing stamina and it is believed to be better than American Sildenafil (Viagra)," the information sheet inside the packet says.
The box even has customer reviews on the back. A 35-year-old man, identified as Woo, raved about the product: "I was able to have a cute baby after using 10 boxes of this medicine, whereas all I had before was dead sperm."
While the claims are almost certainly exaggerated, not all of North Korea's boasts are empty, said Lee Hye Kyung, who worked as a pharmacist at a hospital in North Korea and is now licensed to practice in South Korea.
"Don't underestimate North Korea," Lee said. "The only real difference between pharmacists in North and South is infrastructure - in the North they don't have electricity or raw ingredients, but their technical skills are good."
Indeed, North Korea's pharmaceutical factories have largely ground to a halt along with the rest of the industrial sector, and many pharmaceutical products are imported from China to be sold in the markets. Medicines for chronic outbreaks are donated by humanitarian organisations, such as the drugs that are imported from South Korea to treat multi-drug resistant tuberculosis.
When it comes to Neo-Viagra, although its packaging is entirely in Korean, it appears to be a product made for export.
Neo-Viagra and other medicines - among them Kumdang, which when injected can purportedly cure MERS and avian flu - are not prescribed for domestic use but are used to earn foreign currency, said Kim Jung Ryong, a South Korean doctor who worked in the inter-Korean industrial park on the northern side of the border for seven years, until 2012.
Websites based in China and Russia have been selling Kumdang; Neo-Viagra; Tetrodocain, which purports to treat an array of diseases including tuberculosis and HIV; and Chonghwal, which is said to do the same job as Viagra.
This is a source of pride as well as cash, said Kim. "For North Korea, the propaganda effect is as important as making profits," he said. "A new drug invented in North Korea using North Korean technology can boost pride among people if it is promoted as being effective against serious illnesses."
But for cash-strapped North Korea, the importance of finding new sources of revenue should never be discounted.
Over the years, North Korea has been nabbed counterfeiting everything from Marlboros to Benjamins. In the mid-2000s, it was making imitation Viagra in authentic-looking boxes, although the pills were round and white instead of blue and diamond-shaped.
After several high-profile busts of methamphetamine shipments and US$100 "supernote" trade in the mid-2000s, North Korea appears to have cleaned up its act. This is not necessarily because North Korea is no longer involved in illicit activities, but more likely because it has diversified into new areas, said Sheena Chestnut Greitens, an expert on North Korea's illicit activities.
"They're highly creative and highly adaptable. They're always developing new layers of business," said Greitens, who is affiliated with the Brookings Institution. "If one of their businesses gets busted, they've already been testing others."
By experimenting with new money-making schemes, North Korea has been able to skirt new layers of sanctions aimed at cutting off its ability to finance its nuclear and missile programmes.
If one of their businesses gets busted, they've already been testing others
North Korea is marketing Neo-Viagra as an herbal product even though it contains a synthetic pharmaceutical. But it could become a new and valuable source of revenue.
"If this stuff works, and even if they're only selling it across the border to China, that could be very appealing to Chinese consumers," Greitens said. Chinese consumers have been known to flock to all sorts of purportedly aphrodisiac products, from ginseng and caterpillar fungus to deer or ox penis.
While each area of business in itself won't solve North Korea's economic problems, together they added up.
"I think it's by having this cluster of activities and abilities that has helped them as sanctions have been applied," Greitens said. "With the newest round of sanctions, my guess is that they're doing the same thing: looking for ways to navigate around them."
As it navigates, North Korea is also refining its products. Regular visitors to Pyongyang say the packet used to carry a warning: See your doctor for an erection lasting more than 24 hours. That, at least, has now disappeared.
