Raw egg white contains avidin, which blocks biotin absorption. Sufficient cooking deactivates it, so it's not an issue with hardboiled eggs such as in the context of the OP.
metamorphosis Registered User
How many people eat raw egg whites for brekkie though?!
Well I mentioned it more as an aside, but it can still be there, depending how the eggs are cooked. Frying on a low heat makes nice eggs, but might not be great at deactivating avidin for example.
But yeah it's not a factor in hardboiled eggs anyway.