Halo is very strong and toxic.. mainly I think of it as something only for pre-contest or before a powerlifting meet. Not really good for bodybuilding. The one time I used it I ran either 15 or 20mg/day for just 3 weeks. I got much much stronger very quickly.. so quickly I was worried about my tendons not keeping up so I dropped it. No size gains at all though, just pure strength. If you're experienced and using it for a meet or a competition it's great, otherwise I'd say stay away from it.