What damages collagen? High sugar consumption: a diet high in sugar increases the rate of glycation, a process Ina whereby sugar in the blood attaches to proteins to form new molecules called advanced glycation end products (AGEs). AGEs damage a adjacent proteins and can make collagen dry, brittle, and weak. Smoking: many of the chemicals present in tobacco smoke damage both collagen and elastin in the skin. Nicotine also narrows the blood vessels in the outer layers of the skin, which reduces the delivery of nutrients and oxygen to the skin, compromising skin health.