I agree with Sea Anglers comments. It is better to eat oily fish.
However, if you really want Shark liver oil capsules, find a naturopath or a kinesiologist as they often "prescribe" them as a remedy! In my pre-diagnosis days I spent more £s than I care to remember trying to find cures for my gait problems, including acupuncture (soothing and mentally supportive,but no physical help) chiropractic treatment (helped my lower back pains, but not my gait problems) and kinesiology ( given various remedies including shark liver oil, none made any improvement) . Then along came Madopar . . . Which does actually work some of the time. . . And is free on the NHS, thank goodness!