The authors developed a novel treatment using thioglycolic acid (TGA) to chemically soften pincer nails. The objective was to describe a new treatment method for pincer nails by applying TGA to soften the nail and then fix it in the correct position. A total of 104 patients (nine men and 95 women; mean age, 56 years) with 106 pincer nails underwent our treatment. A small hole was made on the markedly incurvated side of the pincer nail, and a super-elastic wire was inserted into the hole and bent backwards; 5% TGA was then applied for 6–7 h prior to reduction. Favorable reduction was achieved in 66% of patients within 1 day of the procedure, in 30% within 2–4 days and in 4% 5 days or more later. No patient required surgery. No post-procedure infection, rash, continuous pain or nail cut out was evident. In eight cases, recurrences of nail deformity were observed within the 1-year follow-up period. Our novel method, which consists of administrating TGA via a hole in the nail plate, is a useful treatment for pincer nails.