Disclosed is a single-stranded oligonucleotide 8 to 24 nucleotides in length capable of reducing an effective amount of a miRNA in vitro or in a non-human cell or non-human organism, wherein said single stranded oligonucleotide comprises: (i) a sequence that is complementary to a sequence of said miRNA (ii) a sequence comprising not more than 4 consecutive 2-deoxyribose nucleoside (DNA) units (iii) a sequence comprising more than 4 consecutive Locked Nucleic Acid (LNA) units (iv) at least 30% of constituent nucleotides as LNA units and (v) at least one internucleoside linkage group comprising a phosphorothioate, subject to the proviso that the single-stranded oligonucleotide does not comprise a core DNA sequence of 3-ctcaca-5 from positions two to seven or from positions three to eight thereof counting from the 3 end of said oligonucleotide.
