Nettles in Oil

I know that Nettles is a good herb to use for your hair as a tea, I am curious to know if it is possible to use it as an OIL. I did attempt this about a week ago, but after a few days, there was a strange smell.

When herbs are used as a tea the medicinal constituents are extracted by the water. Whether the same medicinal compounds are extracted by oil is not known, but we would guess no. Water and oil extract compounds of opposite ends of the hydrophilicity (water attracting) scale. Compounds that are extracted by water are hydrophilic and compounds that are extracted by oil are hydrophobic. Very few compounds are extracted by both water and oil.
What is causing the smell? The nettle oil is probably degrading because of fungi or bacteria.