What are the ingredients used to make hyaluronic acid fillers like Restylane and Juverderm?

The Juvederm website has lots of information you may find helpful. There is detailed product information as well as clinical studies you can review. HA fillers sometimes have lidocaine added for comfort during treatment.

Thanks for your question. Dermal fillers will provide more significant benefit in two different ways. First, these formulations only contain hyaluronic acid, water, and lidocaine in some cases, which is a numbing medication that makes the treatment more comfortable. Second, these treatments also work deep into the dermal structure so that they can smooth away lines and wrinkles from the inside out. The procedures also last for many months, making them more convenient than topical solutions that need to be applied once or twice a day. Schedule your treatment with a board-certified cosmetic dermatologist that specializes in injectable treatments to ensure an optimal outcome.

The only "chemical" contained in most hyaluronic acid fillers is lidocaine which is a numbing agent added to decrease the discomfort of the injection.  Not all of the HA fillers contain lidocaine but the ones that do are more common and are usually preferred.  Otherwise the only ingredients in fillers are hyaluronic acid and water.  Hyaluronic acid is a naturally occurring substance in the body, found in the highest concentrations in skin, connective tissue, and eyes.  Its main function is to retain water to keep tissues well lubricated and moist.  Because it is a naturally occurring substance, it is felt to be safe for oral, topical, and injectable use.  Hope this helps!