Hi mate. It’s good that you reached out to us, because using testosterone at 18 is a serious mistake, as it can cause long-term and possibly even irreversible consequences for your body.
There is no way to avoid shutting down your natural testosterone production, whether you’re 18 or an adult man. The difference is that in an adult, the reproductive hormonal system is already fully developed, and after using steroids we aim to restore natural testosterone production back to its original levels. In your case, there’s nothing to restore it back to yet because the system is still developing, and interfering with it can disrupt the system itself and prevent it from fully developing.