Some people experience a sore throat, muscle pains and strong-smelling urine when first using electronic cigarettes. It's possible these symptoms are a result of vaping PG-based e liquid. Because propylene glycol is a humectant (attracts moisture), it can dry your throat and leave it feeling sore. PG may also increase the body's production of lactic acid which could cause the muscle aches that some experience from time to time. Most people find that drinking more fluids helps to flush lactic acid through the body more quickly which often resolves the problem. The sore throat should disappear on its own within a day or two, although increased fluid intake will help with this too. If any of these symptoms persist or you begin to suffer from night sweats, diarrhoea or break out in a rash, you may have an allergy to propylene glycol. We recommend you seek the advice of your GP and switch to a VG-based e-liquid if you suffer from any of the symptoms above.