Injecting hyaluronic acid can normally last 6-12 months, but how long it can last is related to the type of hyaluronic acid and post-filling care. 1. The type of hyaluronic acid: hyaluronic acid can be divided into small molecule, medium molecule and large molecule hyaluronic acid, different types of hyaluronic acid, maintain the effect of different length of time. Generally speaking, large molecule hyaluronic acid maintains a longer time and has a better effect of filling and shaping, while small molecule hyaluronic acid maintains a shorter time. 2. Post-filling care: scientific care after filling also affects the maintenance time of hyaluronic acid injection. If you don’t pay attention to the cleaning and drying of the injection site after filling, the improper mechanical rubbing or friction on the filling site in daily life will have certain influence on the maintenance time of hyaluronic acid injection. The duration of hyaluronic acid injection varies from person to person, because hyaluronic acid filling is an invasive operation, which requires a high level of professional and technical skills of the operator, if you need to maintain good results need to be injected on a regular basis, it is recommended to go to a regular hospital for treatment, operated by professional doctors.