Valid concern.
The best way to avoid "degradation" from temperature with peptides & hgh is to change it gradually.
For example, if the hGH is in the freezer... place from there to the fridge for a couple days to gradually thaw. Then, from fridge to room temperature and give it enough time at room temp to match your bac water temp (if that's at room temp). You want your bac at room temp anyway. Then, when both powder and bac are at same temp, mix/reconstitute.
It's when the powder and the bac water are at significantly different temperatures where instability occurs, like cloudy mix. That cloudiness should subside anyway, but yes, possible some degradation may occur.