Curcumin dietary supplements containing curcumin root extract are another form of curcumin intake. Supplement labels will indicate different percentages of curcumin extract. Independent quality control and quality assurance laboratories test and inspect the product to verify these claims and endorse the label as directed by the manufacturer of the product. Some curcumin dietary supplement formulations may also contain other extracts, such as black pepper extract (piperine) or proprietary mixtures containing vegetable gums, or other lipid preparations, in an attempt to improve the bioavailability of curcumin. In particular, research has shown that curcumin can be used as a topical agent in formulations of collagen films, lotions, sponges and bandages to promote healthy skin.