If my garlic has sprouted, can I still use it?

Yes, you can use it. It will not appreciably affect the flavor.

I searched a Dutch site which stated that when they are shriveled or sprouted they are no longer good (to use).
But my own experience is that if you cut out the green inside (and the sprouted part) there is no problem whatsoever.

The cloves that sprouted may be a bit mushy, but the green sprouts are pretty tasty, I mince them and use them in whatever.

I just peel them and use them as normal, and I’m still living to write this. ;) I haven’t noticed much of a change in flavor, although I’ve heard people say that the green sprout is more bitter.

Here’s a link to information about green garlic and garlic scapes. Although it’s not precisely the same thing as what you’re asking about, the green bits of garlic do have culinary uses.

Yes, you can even use the sprouted leaves for cooking. We do it all the time. Not much difference.

At my farmer’s market, they sell garlic shoots in the spring. They are very powerful. It’s different in flavor, but not that different. I used it in humus once, and it was a little too powerful for me.

So, yes, you can use it. Just be careful for when the cloves go soft or moldy or brown. If the shoot has grown too much, it takes all the good out of the clove.