Road2HardCoreIron

I’ve warned many to stop this practice:

Preloading testosterone into a plastic syringe is not recommended because the oil-based carrier can degrade the plastic over time, potentially contaminating the hormone solution. Manufacturers use glass vials for long-term storage because they are the most stable material for holding injectable medications.
The primary risks of preloading testosterone into a plastic syringe for more than a brief period include:
Contamination from leached chemicals. Testosterone for injection is typically suspended in an oil-based carrier, and long-term contact with oil can degrade the plastic of the syringe. Chemicals from the plastic, such as phthalates, can leach into the oil solution. Phthalates are known endocrine disruptors and have been linked to reduced testosterone levels.
Loss of potency. The degradation of the plastic and the leaching of chemicals can compromise the stability and sterility of the testosterone solution over time, reducing its effectiveness.
Compromised sterility. Once drawn from the vial, the medication is no longer in a closed, sterile system. The longer it is stored in a syringe, the greater the risk of bacterial contamination. Reusing syringes is particularly dangerous and can lead to serious infections.
Plunger absorption. The oil in the testosterone can cause the rubber plunger of the syringe to swell or degrade, potentially absorbing part of the medication. This can lead to an inaccurate dose when the injection is finally administered.
Official guidelines and best practices
Medical professionals, health organizations, and product manufacturers advise against preloading for storage, recommending instead to draw and inject the medication immediately. The U.S. Food and Drug Administration (FDA) has issued warnings against pre-filling syringes for storage due to risks of contamination and loss of potency. The manufacturer's instructions for any injectable medication, including testosterone, should always be followed to ensure its safety and effectiveness.