It's a liquid rocket engine fuel that Kim Jong-un and his team of scientists depend on.
Without Unsymmetrical di-methyl-hydrazine (UDMH), North Korea's leader wouldn't be able to fire off his new generation of missiles.
UDHM is the fuel in the propellant combination used to launch the Hwasong-12 intermediate-range ballistic missile (IRBM) and Hwasong-14 intercontinental ballistic missile (ICBM).
Now a revealing analysis by 38 North indicates several production sites where Pyongyang could be making UDHM instead of relying on overseas sources.
While most analysts agree North Korea has the scientific and industrial capability to produce UDMH, none have found direct evidence supporting this conclusion.
The development of the Hwasong-12 IRBM and Hwasong-14 ICBM missiles and tightening sanctions have seen demand for the vital product increase.
The 38 North analysis looks at several areas where the regime could be producing the fuel with other areas also identified as other potential manufacturing sites.
Written by Joseph S Bermudez Jr, the analysis notes production of the fuel could be taking place at the February 8 Vinalon Complex in Hungnam.
According to Bermudez this complex "contains production lines for both chlorine and ammonia, chemicals used in the production of hydrazine, the presence of waste water ponds, and recent construction activities within the complex".
Another site, the July 27 Factory (or the Aoji-ri Chemical Complex) is identified as another potential factory.
"These requirements for UDMH were likely initially satisfied by acquisition of limited quantities from abroad," Bermudez writes.
"Increasing demands during the past 10 years, however, have likely led to both the acquisition of additional quantities of UDMH where possible and the acquisition or development of technology."
Research Associate at California's James Martin Centre for Nonproliferation Studies Shea Cotton said the 38 North analysis is part of on an ongoing "debate" on North Korea's missile capabilities and this part focuses on whether North Korea can make its own rocket fuel (UDMH).
Cotton said the debate has been going on for some time but has gained traction in recent weeks following a September article in the New York Times by journalist David Sanger, which discussed whether North Korea could make its own fuel.
Cotton's own boss, Jeffery Lewis, argued Pyongyang could make its own fuel and surveyed scientific papers published by North Koreans, several of which specifically dealt with UDMH storage and production.
"It appears that this article from 38 North is agreeing with Jeffrey's piece and also suggests other possible production sights," Cotton said.
However, he said it wasn't always easy to identify if a facility could make UDHM.
"The thing with UDMH production is that the production facilities required to make it look a lot any other chemical production facility," he said.
"So it's hard to know if you've found one just by looking at satellite pictures. In this piece from 38 North it looks like they found a few potential sights."
Cotton said even if such sites existed it didn't necessarily mean North Korea was gearing up for more missile tests.
"It just means that they have the means to produce their own rocket fuel, and probably a lot of it too," he said.
"It also means we won't be able to halt their program just by turning off the spigot.
"The unfortunate truth this program is that it's a very sophisticate program which the North Koreans have laboured over for years now.
"They've meticulously built up their production capacity and are constantly improving their program. There isn't an easy fix for this program and the existence of facilities like this proves it."
Nuclear disarmament campaigner John Hallam agreed this didn't mean a new missile test was imminent.
"The existence of extensive facilities for UDMH production does however indicate that the DPRK prioritises it highly and doesn't want to be reliant on outside suppliers," he said.
Hallam said there has been talk in recent days with some arguing the DPRK missile program could be "strangled" by cutting off UDMH, but this doesn't appear to be the case at all.
"In fact I imagine that with three or four UDMH production facilities, the DPRK might even be looking to export some production," he said.
"I still assume there will, sometime, be either a nuke test or a missile test, and maybe the rumoured end to end test is still on the agenda. But it's been awfully quiet lately - that may be just Kim's way of trying to take the temperature down."