Skip to main content Link Menu Expand (external link) Document Search Copy Copied

How Much Benzyl Benzoate is Required to Stay in Solution?

In planning stages


Benzyl benzoate (BB) is a solvent in most HRT injectable recipes. It helps to absorb the hormone powder and blend it with the carrier oil. We are unable to find data that can help us determine just how much BB is needed to hold estradiol and testosterone esters in solution.

Par Pharmaceuticals uses 43% BB by weight in their 40mg/mL estradiol valerate and 23% BB in their 20mg/mL.1

For now it’s not worth the time to redo the work that Par Pharmaceuticals has done. However it may not be fair to say that the concentrations they’re using for EV also apply to other hormone esters like EEn. Make vials of 40mg/mL EEn at concentrations of 0%, 14%, 28%, and 43% BB. Use temperature fluctuations to attempt to get them to fall out of solution.

References and Notes