Does FDA have an Upper Limit for potassium? 

CRN Member query:

"...I have a regulatory question regarding allowable potassium amounts that I'm hoping CRN can help me sort out. I've seen some wording about FDA regulations and potassium amounts not to exceed 99 mg, but I can't find anything about it in the 21 CFR. In fact, there are several examples of much higher K amounts used throughout the CFR, which makes me even more confused.

Hoping you might be able to link me with someone who can add some clarity on this topic? As always, greatly appreciate any help and time you can provide! Looking forward to some insight..."

CRN responds:

"The upper limit of 99 mg per dose for potassium is specific to OTC drugs—FDA has not actually ruled or commented on potassium in dietary supplements. However, in practice, manufacturers have followed this limit due to the safety concerns expressed by the agency (and the requirement to label OTC products with a warning statement if they contain more than 100 mg potassium/serving) and the similar concerns for OTC drugs and supplements. CRN raised the issue in its comments to FDA back in 2014, related to the revision of the nutrition and supplement facts labeling.

This same issue is addressed in the ODS (NIH) recently updated Potassium Fact Sheet.

Bottom line is that FDA has not ruled on a limit for potassium in supplements—or any other nutrient for that matter, as FDA does not set maximums for supplements. But due to the nature of the safety concern, which presumably would apply to supplements and OTC drugs equally, it would be prudent for manufacturers to stick with the less than 100 mg limit or consider the warning statement for liability reasons."