The studies showing clenbuterol being anti-catabolic were done in RATS
No study ever done in humans has shown the same results.
Clenbuterol is NOT anti-catabolic and in fact, it's a terrible thing to include in a PCT. In a PCT, your hormones are low and your body is under a lot of stress. Adding in a very harsh stimulant like clen is a terrible idea. It's going to raise cortisol levels even higher and greatly increase your risk of muscle loss.