The NHL Players’ Association has approved a rule to prevent teams from using vitamin supplements during the pre-season.
The league has banned the use of the mineral supplements in training camp.
The union has also said players should only take them during the regular season.
The NHLPA is expected to vote on the rule Thursday.
It will also prohibit the use during a game of vitamin supplements in the playoffs and in the Stanley Cup Final.
The rule was first approved by the union in June.
In its ruling, the union said it had determined that it was necessary to take such steps because of the significant health risks associated with vitamin supplements.
Players and fans have been asked to take vitamin supplements throughout the season.
The league is using the term “preseason” to refer to the practice of supplementing players with vitamin pills during the first two weeks of the regular campaign.
The union said that while there are several supplements in use, most players use only a small number of them during training camp, during the season, and during the Stanley Final.
In recent years, the use has increased to the point where it has become a common practice in the sport.
In a previous ruling, NHL players were required to take two vitamin pills daily for health reasons.
The rule was updated in 2012 to remove the requirement.
The new rule would also make it illegal for teams to give supplements to players during a pre-game break.
The NBA and MLB have similar rules.
The NBA has prohibited the use or distribution of vitamin pills and other nutritional supplements during pre- and post-game rest periods, and has said players shouldn’t take them before games.