Good point. The Wiki article on SHBG says 3β-androstanediol has the same binding affinity as DHT. So free levels may be relatively low.I think you’d need to know its binding affinity to SHBG to be able to guess at that. E.g. if it had very high SHBG affinity (much more than estradiol), then it’s less likely to have more free molecules. I wasn’t able to figure it out with a quick search.