4 ms·I don’t think we can call 4-5k IU’s of D3 a day ‘megadosing.’ megadosing is more like 50-100k at a time.by jeanofthedead 3y agoI don’t think we can call 4-5k IU’s of D3 a day ‘megadosing.’ megadosing is more like 50-100k at a time.