LOS ANGELES — Out of all the talk of picograms, long-term metabolites and adverse findings, there was one pivotal thing that determined whether or not Jon Jones would fight this weekend.

California State Athletic Commission (CSAC) executive officer Andy Foster told MMA Fighting that, after reviewing multiple statements from scientists and experts, there was something that stood out above all the rest, swaying his choice to allow Jones to fight Alexander Gustafsson in the main event of UFC 232 on Saturday in Inglewood, Calif.

It was a single line from a letter written by Dr. Daniel Eichner, the director at Sports Medicine Research and Testing Laboratory (SMRTL), the World Anti-Doping Agency (WADA)-accredited lab in Salt Lake City. That line read: “There is no evidence that DHCMT has been re-administered,” per the document obtained from the commission.

In other words, Eichner found no evidence that Jones took any new prohibited substance that would have triggered adverse findings in multiple drug-test results over the last four months. Eichner, whose lab analyzed Jones’ tests, wrote that the “most likely” cause of the long-term metabolite of the steroid Turinabol (4-chloro-18-nor-17β-hydroxymethyl,17α-methyl-5α-androst-13-en-3α-ol (M3)) still being in Jones’ system was due to “residual levels from a previous exposure.” The low levels of the M3 metabolite were “not indicative of further exposure,” he wrote.

Jones was already suspended in his case with USADA, the UFC’s anti-doping partner, for a positive drug test for Turinabol metabolites stemming from a July 2017 sample collection. CSAC fined Jones $205,000 and revoked his license in February for the violation. If this was the same metabolite from last year cropping up again and no evidence Jones ingested something new since then, Foster felt like he could not make a case against Jones competing.

“That one line was the most important thing in all of these letters,” Foster said. “I looked at all of them. But what I was trying to differentiate was, is this something that is new? Does the evidence point to a new doping violation or is it the same long-term metabolite that I heard can keep reappearing? So when he wrote there’s no new evidence of DHCMT administration, that was a definitive statement.”

So, Foster gave the go-ahead last weekend. Jones could fight Gustafsson at The Forum on Dec. 29 in California for the UFC light heavyweight title. The UFC then uprooted the entire UFC 232 card last Sunday, moving it from Las Vegas to the Los Angeles area. Jones would not be licensed in time by the Nevada Athletic Commission (NAC), which wanted him to come in for a hearing. The NAC allowed Jones to withdraw his license application pending a hearing next month.

There were two last things Foster needed before making it official. Jones had to submit to and pass a steroid test. The former UFC light heavyweight had to take a private jet last Saturday from his home in Albuquerque, N.M., to San Dimas, Calif. There, he had a sample collected and then tested at the non-WADA certified KorvaLabs. The expedited results came back Sunday and found that Jones was clean of active steroids. In addition, CSAC asked Jones to enroll with the Voluntary Anti-Doping Agency (VADA), which has no financial relationship with the UFC, unlike USADA.

All of those things were good enough for the California commission to allow Jones to fight. USADA concurs — Jones is not facing a new UFC anti-doping policy violation. But for many, from Jones’ rival and UFC heavyweight champion Daniel Cormier to countless fans, none of this makes any sense.

There are still many questions, some of which cannot be answered by published, peer-reviewed science. How could a steroid metabolite remain in Jones’ system for 17 months or longer? Does that steroid metabolite — as small as it may be — have any performance-enhancing benefits? And even if it doesn’t, should someone still be allowed to compete with something like that in their system? Jones, for his part, has vehemently denied that he knowingly took any prohibited substances, though he was unable to come up with proof of ingestion of a contaminated supplement.

The most recent published science on oral Turinabol was in 2011, a study done by Russian scientists Tim Sobolevsky and Grigory Rodchenkov. The study estimates that the detection window of the M3 metabolite (the one found in Jones’ system) is 40 to 50 days.

Oliver Catlin, anti-doping expert and president of the Banned Substances Control Group, said the Sobolevsky-Rodchenkov work is “the seminal publication on detection of oral Turinabol.” Catlin said he heard a webcast from Dr. Larry Bowers, the retired former USADA director of science, that stated the longest term Turinabol metabolite “could be as long as six to nine months.”

UFC vice president of athlete health and performance Jeff Novitzky, who has nearly two decades of experience working in anti-doping, and USADA argued this week that the science and testing has advanced since 2011 and it’s difficult to perform administration studies with Turinabol, because it is an illegal drug.

USADA director of science Dr. Matt Fedoruk said in a statement that the agency reviewed the details of more than 20 DHCMT M3 metabolite cases, similar to the one with Jones, where there were sufficient tests and investigations completed, before coming to its conclusion. Novitzky said USADA also was in touch with other sports leagues who had similar cases. And there has been one case like this in the UFC, a recent one involving fighter Grant Dawson, whose potential violation was dismissed by USADA earlier this month.

With Dawson, Novitzky said it was determined that he did not take Turinabol any time recently, but the findings were from the long-term M3 metabolite that had lingered in his system, perhaps for years, long before he was in the UFC. Dawson did not return a request for comment Friday. Regarding the Jones case, Fedoruk said that “determination of the circumstances of ingestion” becomes more difficult when it’s only the long-term metabolite — and no parent or other metabolites — detected.

MMA Fighting reached out to Sobolevsky, who declined to comment on this case.

“I do not think it is a good idea for me to speak publicly on this controversial topic,” Sobolevsky wrote in an e-mail.

Multiple other scientists and anti-doping experts reached also did not want to discuss the situation on the record. An e-mail message sent to Eichner was not returned.

Bowers himself wrote a letter to USADA regarding the Jones case, which was then passed on to the California commission. MMA Fighting obtained the letter via a public records request. Bowers’ conclusions were flimsier than the ones Eichner came to regarding when Jones may have ingested the Turinabol. Bowers concluded that Jones had not ingested anything new from August 2018 to December 2018, but that’s about all.

“In conclusion, I cannot determine with any certainty when, at what dose, or what chlorinated anabolic steroid was ingested that gave rise to the July, 2017 result,” Bowers wrote. “Based on the data provided, I conclude that no DHCMT exposure occurred between August, 2018 and December, 2018. I cannot exclude the possibility that the December 9, 2018 result arose from an exposure before July, 2017.”

The August 2018 mention is significant, because Jones, while under 15-month suspension from the July 2017 positive, was not tested by USADA for about 10 months, from October 2017 to August 2018. Jones was facing a four-year ban as a repeat offender, but that was reduced to 18 months when Jones provided “substantial assistance,” or cooperation in an undisclosed, separate case. The suspension was reduced again to 15 months when arbitrator Richard McLaren determined that Jones did not likely intentionally ingest a prohibited substance.

Jones, 31, tested positive for the metabolite in an in-competition test related to his UFC 214 fight in July 2017. Earlier that month, Jones passed two out-of-competition drug tests. He then passed the one in October 2017. Since then, the M3 metabolite was back in tests done in August 2018 and September 2018, was gone in four tests done between September 2018 and November 2018 and came back in the Dec. 9 sample collection, which ultimately led to the Nevada commission balking on licensing Jones in time for UFC 232.

Novitzky described the inconsistent detection of the metabolite in tests as “pulsing.” Bowers wrote that the “appearance and disappearance” of the metabolite is “not unique to M3 of DHMCT.”

“In this case, the detection of the single long term M3 metabolite at the tail end of the detection window and combined with the aforementioned factors, makes detection challenging – so a pattern of detection in some samples and absence in others is not uncommon,” Fedoruk wrote.

Eichner wrote that since evidence indicates that the ultra-trace metabolite — at the single- or double-digit picogram level — in Jones’ system is “most likely” residuals from a previous exposure, “there is no scientific or medical evidence that the athlete would have an unfair advantage leading up to the competition or for a competition in December 2018.”

Novitzky said there’s a school of thought that perhaps the testing has gotten almost too advanced and that detection of such a small amount might actually be going overboard. WADA certification can be given to any lab that will test at a minimum of 2 ng/ml, which is multiples higher than picograms.

There have been cases in other sports with the execution of strict liability — if there’s a prohibited substance in someone’s system, no matter the level, that athlete should be sanctioned, even if it’s for the same metabolite that previously turned up. Major League Baseball player Cody Stanley has had his career effectively ended due to multiple positive drug tests for the M4 metabolite of Turinabol. MLB treated some of his adverse tests as one violation, but others independently of one another. Stanley was banned for a full, 162-game season in 2016 and has not played since. MLB and USADA are both co-founders of the Partnership for Clean Competition, yet the adjudication processes here seem inconsistent.

“The decision to treat the findings independently in Mr. Stanley’s case would seem justified according to the timeframe of detection indicated in the [Sobolevsky] literature, but perhaps not so if compared with the timeframe of detection suggested to be relevant in Mr. Jones case,” Catlin said.

In another similar case, the NCAA reinstated basketball player Allonzo Trier earlier this year after he was initially suspended after coming to the conclusion that he tested positive for a remnant of the substance he was previously sanctioned for.

There are legitimate reasons to look at this situation with skepticism. The UFC has presented inconsistencies. UFC president Dana White said multiple times earlier this week that the Dec. 9 test was the only one of Jones’ that came back adverse. Novitzky revealed Thursday on Joe Rogan’s podcast that Jones had the M3 metabolite in his system in August and September.

That information was not given to the Nevada commission, which was supposed to be sanctioning UFC 232, until early December. And it was not given to the California commission before its licensing hearing for Jones on Dec. 11. Jones’ license was revoked in California back in February for the July 2017 positive drug test and he needed to go back in front of the commission to get it back. Novitzky admitted Friday that those could have been oversights.

“No, they didn’t,” Novitzky said when asked if CSAC knew Dec. 11. “Nevada knew at that time, but California didn’t. … I mean, hey, in hindsight, maybe [USADA should have told CSAC]. I’m definitely a proponent in as much transparency as possible. Unfortunately, how do you think of every scenario? I think in USADA’s mind, they had no obligation to let Nevada know about this at all. It wasn’t within their jurisdiction. I think out of an abundance of caution, they did it. Could they have given it to [CSAC] as well? I think potentially.”

Had CSAC known earlier this month about the adverse findings, it’s possible there could have been a full hearing on the matter, which the Nevada commission is asking for next month. Ultimately, Foster did eventually rule to allow Jones to compete Saturday after seeking out experts.

One question that may never be answered is just exactly how Jones ended up with a long-term Turinabol metabolite in his system and how long it has been there. Novitzky said it’s likely not due to micro-dosing, because that is more common with endogenous agonists, or drugs native to the body like testosterone. Catlin said he had never heard of micro-dosing Turinabol, but “some people could try to micro-dose just about any doping agent.”

Victor Conte, the former Bay Area Laboratory Co-operative (BALCO) founder infamous for his distributing steroids to athletes, said he has seen cases where an athlete takes testosterone and ends up testing positive for the anabolic steroid nandrolone. Conte attributes that to underground labs and cross contamination.

“Was it a contaminated nutritional supplement that [Jones] bought over the counter?” said Conte, a sports nutritionist who is now working again with athletes as the CEO of Scientific Nutrition for Advanced Conditioning. “Was it a contaminated underground steroid that had been manufactured? You can buy testosterone and test positive for nandrolone, because you get this ultra-trace cross contamination.”

Another wrinkle in all of this is Jones’ other positive drug test for the anti-estrogen agents clomiphene and Letrozol in July 2016. He served a one-year suspension in his USADA case for that violation, which Jones explained as coming from tainted sexual enhancement pills.

Conte said that positive test makes things “highly suspicious,” because of those drugs’ roles as post-cycle therapy for steroid users. Conte said he has been questioning Jones going back to 2015 when lab results came back showing Jones had lower levels of testosterone than he deemed normal.

“That in itself, it’s like what caused that?” Conte said “That’s cause for suspicion. It’s like where there’s smoke, there’s fire.”