Most of our lipid products are supplied neat (i.e., they are not dissolved in a solvent) and will appear as an oily liquid coating the inside of the vial. Lipids will typically need to be dissolved in order to recover the material from the vial. Add an appropriate amount of solvent (solubility information will be provided on the datasheet for the specific lipid you purchased) to the vial, vortex briefly, and then retrieve the resulting solution for use (or aliquot for later use if desired).
Note: lipids that are supplied neat are pure substances, and can be treated exactly as you would solids for purposes of molar concentration calculations etc. Please contact our technical support for more product-specific recommendations regarding reconstitution of individual compounds.