The testosterone enanthate is available in various formulations, containing preservatives like benzyl benzoate or benzyl alcohol.
Testosterone enanthate has been designed to gradually release from the depot of the injection site which is intended to be a deep intramuscular injection with a 1-1.25" needle.
In general, all testosterone injections are equal once they cleave from their ester. The rate of release and the excipients (inactive substance or ingredient) used as a preservative can affect its tolerability by the patient.
Allergies to the excipients, such as arachis oil or castor oil, would preclude a patient from using such a preparation.
In Europe, certain brands of testosterone enanthate do contain arachis oil which is a type of peanut-based oil. So, it's important to inform your doctor of any allergies should you be prescribed testosterone injections.
The oily solution that is testosterone enanthate should be injected immediately after suction into the syringe (as recommended by Norma – one of the manufacturers of testosterone enanthate).
This means ensuring that you do not store any remaining contents of the ampoule in another syringe or in a separate vial.
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