Just as a fun idea: by way of warning, I've never tried it.
What one could try would be to attempt to dissolve in as much alcohol as one is willing to use. In your case that is one mL per 20 mg of oxandrolone.
If this is insufficient, as it appears it will be, start adding glycerin. In this case I would try adding an equal volume first. In other words say I'd, as a first test, tried dissolving 100 mg of oxandrolone and being willing to use only that amount of 80% alcohol, therefore used only 5 mL of alcohol.
Now exactly why I'd be so chintzy with the alcohol, I cannot imagine. If I wanted to use 100 mg/day, which is a lot and is more than most use, and I went for 10 mg/mL I'd need only 10 mL alcohol which is one-THIRD of a "drink." And if I divided that into say four doses per day, I'd be having one-TWELFTH of a "drink" each time.
But let's say I am too stubborn and am just dedicated to the proposition that I won't use more alcohol than that.
So in this instance, I first add 5 mL glycerin as well.
This will likely dissolve the remainder. If so, very good.
If not, then it could be left alone, and at least the amount dissolved would be greater and the amount suspended less, and the solution would be much thicker so the settling rate would be much slower, allowing for more accurate dispensing.
Or I could try adding another 5 mL glycerol. (Glycerol = glycerine, btw.)