No, heads up is used to give someone information you think would be helpful to them. The assumption is usually that they don’t know this information, so it’s not a reminder. Here are some examples. I just wanted to give you a heads up that your boss is upset about how the meeting went. Here’s a heads up: if you want to swim safely in the open water you should have a partner. The second one is closer to a reminder, but is still told with the idea that the person might not already know that.

"Heads up" is a colloquial expression which is not quite the same as a reminder. A reminder is telling someone something that they should already know but may have forgotten. A "heads up" is telling someone or warning them about something they may not know.