Silica and vitamin C are the two most important nutrients needed to rebuild the collagen and elastin in the tendons and ligaments. In addition gelatin will provide the amino acids needed for the collagen and elastin.
Collagen and elastin consist of silica, vitamin C, sulfur, glycine, proline, hydroxyproline, lysine, hydroxylysine and utilize traces of copper and zinc as catalysts for their formation.
Nettle leaf is a great source of silica, vitamin C, sulfur, copper, zinc, amino acids and also helps with reducing inflammation.
What about irish moss for gelatin? Is there a vegan sub?
Irish moss is a mucopolysaccharide source, which will give it the same gelling properties of gelatin, but it does not have the amino acid profile of gelatin. Gelatin is made from connective tissue and thus consists of the amino acids needed for the production of connective tissue. Even though you will get glycine, lysine and proline in Irish moss the amounts are rather small. If you want to avoid the gelatin I would get these individual amino acids as supplements.