Under the ACA, you estimate your income for the year when signing up for a health insurance plan via the exchange. If you are eligible for a subsidy, it is calculated based on this estimated income, and your monthly premium is then calculated with the subsidy taken into account. If at the end of the year it turns out your income was higher than you thought, you must repay the excess subsidy, and if your income was lower than you thought, you can receive a credit for the subsidy you should have received.
Self-employed individuals can deduct health insurance premiums as an "adjustment to income" on line 29 of the 1040.
My question is, does the premium tax credit repayment as described above count as a deductible "health insurance premium"? For instance, suppose as a self-employed individual I paid $1200 for health insurance premiums over the course of the year, but then at the end of the year it turns out my subsidy was in excess, and I now owe an additional $300 in premium tax credit repayment. On line 29 of my 1040 (self-employed health insurance deduction), can I enter $1500, or only $1200? Or, conversely, if it turns out I'm eligible to get $300 back because I was eligible for more of a subsidy than I thought, must I deduct only $900?
EDIT: I want to clarify something. Some of the answers below appear to be referring to the general-purpose medical expenses deduction. This is available to all taxpayers, applies to a wide range of medical expenses, applies only to expenses over 10% of AGI, is an itemized deduction, is reported on Schedule A with the rest of the itemized deductions, and thus can only be taken if you itemize deductions. The deduction I am referring to (described here) is for self-employed people only, is not subject to the 10% limit, applies only to insurance premiums, is an adjustment to income (not an ordinary deduction), is taken directly on Form 1040, and hence can be taken even if you don't itemize deductions. I am specifically asking about this self-employment adjustment to income for health insurance premiums, not about the general deduction for medical expenses.