The old and universal dosage of creatine is 5 grams per day. Today, however, this has been refined, and even 10 grams per day can be a useful dose for people with a lot of muscle mass or a high level of activity, for example. On the other hand, benefits have been found even with doses of less than 5 grams. The optimal dosage is therefore individual. For example, research has shown that vegans have smaller creatine stores than usual, so using creatine as a supplement can be more beneficial than usual and grounds for a larger dose. However, a good rule of thumb for the "maximum" dose is approx. own weight/100, i.e. 6g per day for a 60kg person and 10g per day for a 100kg person. Since creatine packs fluid into the muscles, it is recommended to take care of sufficient water intake when using creatine.
When using creatine, we often talk about a "loading period". This refers to how to take a larger amount for the first 5-7 days so that the body's creatine levels rise to the optimal level as quickly as possible. Usually, a suitable dosage during the charging period is approx. 5 times the normal dosage. So, for example, 5g maintenance dose for 25g. During the loading period, the dose should be divided into parts throughout the day, because a large amount at once can cause stomach ache or nausea for some. The loading period is not mandatory, as the body's creatine levels rise to optimal before long even with a normal maintenance dose.