The biological efficacy of alcohols of various chain lengths (i.e., with different numbers of carbon atoms) often displays a so-called cutoff effect (24–27). For the shorter alcohols, the alcohols' potency increases with increasing chain length. Beyond a certain chain length, further increases in length have less effect on potency, and may even reduce it. A cutoff effect is observed in a variety of systems: Alcohols with chain lengths ≤ 6 increase the formation of the photoactivated form of rhodopsin in 1-palmitoyl-2-oleylphosphatidylcholine lipid vesicles, whereas longer alcohols decrease its formation (5). In Xenopus oocytes, ethanol through 1-butanol potentiate nicotinic acetylcholine receptor currents, whereas longer alcohols inhibit them (28). The antimicrobial activity for a range of microbes peaks at alcohol chain lengths varying between 7 and 16 carbons depending on the organism (29), and the anesthetic effect on tadpoles reaches a maximum at 1-dodecanol and 1-tridecanol, with longer alcohols being inactive (9).