Liners (10) are adapted for use with a prosthetic or orthotic device, and provide a barrier and/or interface between a residual limb and a prosthetic socket, or between an orthotic device and the site of application. The prosthetic and orthotic liners include at least one antiperspirant (30), and methods of forming the same in an efficient, reliable manner. The liners (10) may include aluminum-based antiperspirants such as Aluminum Zirconium Tetrachlorohydrex Glycine. The antiperspirants (30) may be provided as a powder or anhydride, may first be constituted in a silicone-oil, and mixed under vacuum. The antiperspirant-oil mixture can be combined with silicone components and mixed under vacuum. The resulting complete mixture is then cast and cured into a silicone elastomer liner (10) with antiperspirant (30) dispersed and/or embedded.