"Usnic acid is a naturally occurring chemical typically found in the Unsnea laevis Nylander (a lichen) native to the Venezuelan Andes mountains1 where the lichen is used by primitive endogenous farmers as an antibiotic. And, not surprisingly, the drug and medical community has been studying the substance for 20 years or so for possible use in a variety of applications.
Most recently, usnic acid, when applied topically, has been found to be quite useful in treating intravaginal genital warts (human papillomavirus lesions),2 being almost 100% effective at destroying the warts when used in conjunction with zinc sulfate. While this is utterly fascinating to the readership, and probably even more so to our promiscuous readers, usnic acid has some other characteristics and uses that I'm sure you'll find a bit more worrisome and more appropriate for a "Consumer Watchdawg" article.
Usnic acid has rather profound antimycobacterial effects against tuberculosis-type organisms3 and its antimitotic (read "stops cell division in its tracks") effects on a cornucopia of biological systems—including humans4—are dangerously intriguing. And yes, much to Duchaine's credit, usnic acid exhibits the characteristics of 2,4-dinitrophenonel (oxidative phosphorylation), at least in vitro against mouse liver mitochondria,5 as it probably penetrates the inner mitochondrial membrane through its lipophilic characteristics.
And since we're speaking of mice and not men (although we can extrapolate the data to men, as mice and men are both mammalian systems), usnic acid has been shown to increase clastogenic (chromosome or gene breaking) action in mouse femur (bone) cells,6 something that I know we all want to avoid unless we're looking forward to osteoporosis, bone cancers, and hip replacement surgery in the near future.
It was also shown in the same study to be a mitodepressive agent, possibly interfering with RNA biosynthesis and causing a marked decrease in "baby erythrocytes" (pre-red blood cells). It's believed that this effect of usnic acid is on the "spindle apparatus" (cell architecture, so to speak) which would put it in a similar category to the noted anticancer drug, Taxol!
Plasma usnic acid levels showed a triexponential elimination with a mean +/- SD terminal half-life of 10.7 +/- 4.6 hr. Peak plasma level (cmax) of 32.5 +/- 6.8 micrograms/ml was achieved in 12.2 +/- 3.8 hr (tmax). Mean absolute bioavailability of usnic acid following oral administration was 77.8%.9 In other words, the body absorbs it rather well, and it hangs around for a long time.
Due to the long half-life and excellent bioavailability of oral usnic acid, it's almost inevitable that no matter what's printed on the warning label on the bottle, someone will overdose and really hurt themselves with this chemical. Also, usnic acid, once inside your bloodstream, is highly protein-bound at a level of approximately 99.2%. Tissue distribution studies of usnic acid undertaken in rats showed that usnic acid was well distributed into well-perfused organs.10 The tissue
lasma ratio in lungs was exceptionally high, which might be advantageous if you have drug-resistant tuberculosis, but this particular property wouldn't help anybody trying to lose fat. In fact, it's readily evident that usnic acid, because it collects in well-perfused organs (heart, liver, kidney, brain, etc.), will most likely manifest symptoms of overdose in these organs. Swell, huh?"