Age or injury-related skeletal muscle atrophy can often induce a host of metabolic diseases. Nutritional interventions have previously been examined in an attempt to identify strategies to minimize skeletal muscle atrophy (1). Recent work has shown that n-3 polyunsaturated fatty acid (n-3 PUFA) supplementation amplifies the anabolic response of human skeletal muscle to amino acid infusion (2). The molecular mechanisms detailing exactly how n-3 PUFA supplementation achieves an increase in the muscle protein synthetic response are yet to be elucidated. The aim of this study was to examine the expression of nutrient-sensitive anabolic signalling proteins at baseline and the time course of any changes over 4 weeks of n-3 PUFA supplementation. Healthy, male humans, (n=10), aged 21 ± 3yrs; body mass 76 ± 5kg (means + SD), consumed 5g.d-1 of fish oil capsules (3500mg eicosapentaenoic acid [EPA]: 900 mg docosahexaenoic acid [DHA]) for 4 weeks. Muscle biopsies were obtained from the vastus lateralis in the fasted state at baseline (-2 and 0 weeks) then at 1, 2 and 4 weeks of n-3 PUFA supplementation. Western blot with zero replicates was performed for assessment of changes in expression of total mammalian target of rapamycin (mTOR), eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), focal adhesion kinase (FAK) and p70S6 kinase (p70S6K). Using a paired T-test it was identified that total mTOR, 4E-BP1, FAK and p70S6K were unchanged between -2 and 0 weeks. Using a single factor (week of supplementation) repeated-measures ANOVA we observed a significant main effect of week for fold change in mTOR (P<0.05), and FAK (P<0.05), but no effect for fold change in p70S6K or 4E-BP1. However, post-hoc comparisons using Bonferroni corrections were unable to detect individual differences between weeks for fold change in mTOR or FAK during the supplementation period. The peak fold change (mean ± SD) was 3.2 ± 2.8 for mTOR (0-2 weeks) and 3.9 ± 4.8 for FAK (0-4 weeks). These data indicate that consumption of 5g.d-1 of fish-oil capsules for 4 weeks may promote an increase in the content of mTOR and FAK. Given that both mTOR and FAK are also known to be sensitive to muscle contraction (3), future research investigating the interaction between exercise, n-3 PUFA supplementation and muscle protein synthesis is warranted.