My titanium rings are perfect for those who have sensitive skin because they are nickel free and won't provoke skin allergies. The most common ailment arising from contact with nickel or its compounds is an allergic dermatitis known as "nickel itch" which usually occurs when the skin is moist.
About 10% of the population is allergic to nickel, often found in gold and white gold. For this reason, the European Union imposed a nickel ban in 2000 on all jewelry sold there. The European nickel free standard specifies that items labeled "nickel free" can only contain a maximum of 0.05% nickel.
Both grades of titanium I use are hypoallergenic (physiologically inert) and will not irritate or discolor your skin. In my research I have found no medically documented cases of skin allergies resulting from wearing a titanium ring.
Titanium is judged to be inert and immune to corrosion by all body fluids and tissue, and thus has high bio-compatibility. These hypoallergenic qualities, plus its strength-to-weight ratio, are the reasons titanium is used for medical implants such as hip joint replacements. In fact, more than 2.2 million pounds of titanium devices of every description and function are implanted in patients worldwide every year!
What about color anodized rings?
The anodizing process forms a titanium-oxide layer on the ring’s surface. Titanium-oxide has the same properties as titanium, so it is hypoallergenic as well. In fact, in the medical industry, titanium screws used to secure implants to bone are often color-coded via anodizing for easy identification of the various sizes.