Medical Beat: What are T/E ratios? And why do cutoff limits vary for testosterone?

Source: mmajunkie
by Dr. Johnny Benjamin


Following UFC 146 headliner Alistair Overeem's failed drug test, my inbox is full of questions regarding T/E ratios and the like.

So maybe it's time for a quick physiology primer for you fight junkies.

Testosterone (T) is the naturally occurring male hormone produced primarily in the testes. Epitestosterone (E) is an inactive form of testosterone that may serve as a storage substance or precursor that gets converted to active T.

Most men have a ratio of T to E of 1:1, which means normal men have equal amounts of T and E in their blood. There is some normal ethnic and time of day variation in the normal T/E ratio (as low as 0.7:1 and as high as 1.3:1).

Statistics reveal that a ratio of up to 3.7:1 will capture 95 percent of all normal men, and a ratio of up to 5:1 will capture greater than 99 percent of all men. That's why the World Anti-Doping Agency (WADA) allows up to 4:1 (so its test is at least 95 percent accurate) and the Nevada State Athletic Commission, the NCAA and some others allow up to 6:1 (for 99 percent accuracy). The whole goal is to not label someone a cheater when he or she isn't. (Very, very rarely, some people are just freakishly high, but they have a ratio of less than 6:1).



Overeem, of course, had an eye-poppin' 14:1 ratio.

T/E ratios are used in performance-enhancing-drug (PED) monitoring because taking an external (exogenous) source of T will not effect the E levels in the blood. E stays the same, but T climbs because of the injection, and the T/E ratio follows suit and climbs.

The half-life of T is only eight hours. So every eight hours, half of the T you took is washed out of your blood. Therefore, if a cheater knows when he is likely to be tested (i.e. post-fight), he doesn't need to be a genius to know when to stop taking ("cycle off") to test lower than 6:1 or 4:1. Twenty-four hours is three half-lives, and virtually none of the extra T is left in your system to get you busted.

T abuse is making a resurgence because of therapeutic-use exemptions (TUE for TRT). Also, it naturally occurs in men's blood – unlike other anabolic steroids that at any level are unnatural (not made within the body) and must be masked in an attempt to beat the test. Cheaters don't have to mask T, so they don't worry about testing positive for a masking agent. They just need enough time for their bodies to get rid of it naturally.

If you don't know when the test is coming, you cannot adequately plan or time when to stop taking a PED like T. This, of course, is the rationale for random testing.

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