How to know the body needs collagen supplements?

A: Basically, after the age of 25, the body begins to reduce collagen biosynthesis. Then from this stage it may be necessary to supplement collagen. Some obvious signs to be able to replenish collagen in time: 
- Unsmooth skin 
- Appearance of wrinkles and spots, freckles. 
- Hair is frizzy and prone to breakage. 
- Fingernails are weak and break easily.