Recently i've heard a lot of people mentioning TIGI's S Factors smoothing lusterizer and from what I had heard it was the exact thing I had been looking for and it has not disappointed me.
You can apply it into wet or dry hair and leaves it feeling silky smooth and super shiney. The product itself contains a slight shimmer which is not noticeable in your hair, but it's what gives it that lovely shine. It also smells AMAZING, almost like strawberries and cream sweets, yum. I have very oily hair and usually find I have to wash it every other day at least but after using this I have found that by days 3 my hair is not at all greasy and still really soft and clean feeling. I've even put some in my extensions to make them blend with my shiney hair as there was quite an obvious difference.
I absolutely love this and will definitely be buying more when mine runs out. I bought mine for £10 on Ebay but it's available on cheapsmells and feelunique