Radiesse is a gel made up of calcium hydroxylapatite, water, glycerin and sodium carboxymethylcellulose. The latter composition acts as an umbrella at the injection site to form new tissue, whilst the gel converts into collagen. What is in the box? Radiesse is available in two sterile, latex free syringe sizes, 0,8ml and 1,5ml. The main ingredient is synthetic calcium hydroxyapatite, a popular component that has been used for decades by leading medical experts in the health industry.