You can enter these expenses in TurboTax Online here:
- Navigate to Federal > Deductions & Credits > Medical Expenses > Start or Edit
- Enter all the expenses you have as you go through the categories
- On the screen "Tell us about any other medical expenses" you can enter the cost of the supplements
Note that in order to claim medical expenses you must itemize deductions and only the expenses over 7.5% of your AGI are deductible.
If you are unable to get to the medical expense entry after following these steps, I would suggest clearing your cookies and cache to start (How to clear your cache).