Insoles are foot supports made of various materials (foam, leather, plastic, fiberglass, graphite) that fit inside shoes. Some are flat, some molded; some have gel fillings. By cushioning and helping support the foot, they can help reduce problems associated with bunions, plantar fasciitis, and some other foot conditions. They can also make foot motion more efficient and correct structural imbalances that cause pain in the knees and hips, and they are good shock absorbers when you exercise.
If you have chronic foot (or other lower-body musculoskeletal) pain, a podiatrist or orthopedist may prescribe custom insoles, which involves making casts or perhaps digital scans of your feet—for about $400 to $600. Some medical insurance plans pay for them. But you may instead decide to try over-the-counter (OTC) insoles, which typically cost $40 or less.
Studies show that the nonprescription variety can be as helpful (or nearly as helpful) as custom ones for certain conditions. For instance, in a 2014 study in Musculoskeletal Care, people with plantar heel pain who wore prefabricated orthotics for eight weeks had the same reductions in pain and disability as their counterparts who wore custom orthotics—at considerably lower cost. Another study, in Prosthetics and Orthotics International in 2015, concluded that using any of the three OTC insoles tested “would be beneficial for the treatment, or prevention, of musculoskeletal injuries such as plantar fasciitis.” The American Orthopaedic Foot & Ankle Society endorses OTC inserts for heel pain.