Cr 24/kg is 27.2 (creatinine clearance). Normal is up to 24. Worried about hyperfiltration, not abnormally muscular. 4 months ago serum creatinine was. 88 and BUN 12. Weight is 195lbs 22% bodyfat.

Hyper-filtration? I do not understand what you mean by "Cr 24/kg" Perhaps one of the nephrologists at HealthTap does but creatinine clearance is a volume per minute measurement and normal value for a 23 year old white male is 90 to 140ml/min and 110 to 170ml/min in black males. Based on your weight, age, and creatinine your clearance is approximately 163ml/min which is excellent (there's no such thing as too high)
Stop worrying, Joe. Get over the idea that "normal range" is healthy range. It's actually the usual value for people who are the doctor. You're young and probably fitter than you give yourself credit for. Forget the "hyperfiltration" stuff you read about and give thanks for good health.