This question was answered in both of the replies you already received. Out of pocket medical expenses for 2025 can be entered for 2025. Whether those expenses have any effect on your tax due or refund is questionable, because first you have to meet the 7.5% of AGI threshold for medical expenses, and also meet the threshold to itemize deductions.
I hope we are not misunderstanding your question. You have mentioned "going back three years" more than once in these posts. Are you asking if you can go back three years and put the past three years of out of pocket health insurance premiums on your upcoming 2025 return? If that is what you are asking, the answer is NO. Only medical expenses paid in 2025 can be entered on a 2025 tax return.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
