How to Reconstitute Sermorelin: Dosing Math (mg, mL, IU, Units)

The whole calculation is one division

Concentration in mg per mL equals the milligrams in the vial divided by the milliliters of diluent added. As a purely illustrative example, a 5 mg vial with 5 mL added is 1 mg/mL; the same vial with 2.5 mL added is 2 mg/mL. If the volume added differs from plan, divide the vial's total milligrams by the volume actually added and recalculate.

From milligrams to marks on a U-100 syringe

At 1 mg/mL, 0.20 mL carries 200 mcg. A U-100 barrel divides 1 mL into 100 units, so one unit is 0.01 mL and 0.20 mL is 20 units. At 2 mg/mL the same dose is half the volume, 0.10 mL or 10 units.

These are general arithmetic examples of how a concentration converts to syringe volume marks. They are not concentrations, reconstitution instructions or doses taken from any sermorelin study or label.

By the same general arithmetic, a U-100 barrel divides 1 mL into 100 marks and a U-40 barrel divides the same 1 mL into 40, so the same mark number is a larger volume on the U-40. Sermorelin is a 29-amino-acid GHRH analogue, not growth hormone itself [3], and Geref's marketed strengths were labeled by weight in milligrams [1].

No approved concentration or shelf life today

Geref's manufacturer discontinued it in 2008, and FDA withdrew approval of both Geref applications effective June 18, 2009. In March 2013, FDA determined that Geref was not withdrawn from sale for reasons of safety or effectiveness [1]. Sermorelin sold in the US today is compounded, and FDA does not review the safety, effectiveness or quality of compounded drugs before they are marketed [2].

The doses that were published

The published dosing comes from the pediatric Geref program and a separate older-men physiology study; neither establishes a reconstitution method or a recommended compounded dose.

In the pediatric program, 110 previously untreated prepubertal children with growth hormone deficiency (86 evaluable for efficacy) received 30 micrograms per kg subcutaneously once daily at bedtime for up to a year; mean height velocity rose from 4.1 cm per year at baseline to 8.0 cm per year at 6 months and 7.2 cm per year at 12 months [4].

In a separate study of 10 healthy older men (mean age 68), participants received 0.5 mg and 1 mg of GHRH(1-29) subcutaneously twice daily for 14 days at each dose, in random order, compared with 9 younger men (mean age 26); at the higher dose, 24-hour growth hormone and IGF-I rose to levels not significantly different from the younger men [5].