The novel devices comprise a housing that preferably contains a preloaded, conventional syringe with medication. Both trained and untrained users may administer an injection safely and conveniently to themselves or others in myriad settings. The disclosed devices rely on the user's manual action to insert the needle. Only after the needle is fully inserted is the medicament delivered, resulting in a safer injection. After use, the devices include a locking mechanism that locks a spring-loaded sheath in place around the needle for protection. As a common syringe is utilized, engineering and production issues of automatic injectors' custom syringe assemblies are avoided.
