Amino acidConditionally essential amino acid

Proline

Also known as L-proline

Proline is a conditionally essential amino acid the body normally makes on its own. It is a major building block of collagen and gives that protein its structural strength, so it is important for skin, joints, and wound healing.

Classification
Conditionally essential amino acid
Type
Amino acid
Grounded in the IOM/NASEM Dietary Reference Intakes and reputable nutrition science.

Why it matters

What it does in your body

  • Major component of collagen
  • Skin, tendon, and cartilage structure
  • Wound healing and tissue repair
  • Building block of protein

Intake guidance

How much you need

There is no daily requirement, because the body synthesizes proline and dietary protein supplies more. Needs can rise during wound healing or heavy tissue repair, when it is considered conditionally essential.

What affects it

What affects your intake

Collagen demand

Because proline is abundant in collagen, needs increase when building or repairing skin, tendons, and cartilage.

Vitamin C pairing

Turning proline into stable collagen requires vitamin C, so both matter for connective tissue.

Diet source

Bone broth, gelatin, dairy, and meat are rich sources.

In practice

Good to know

Good to know: proline works hand in hand with vitamin C to build collagen, which is why both are marketed for skin and joint health. Collagen and gelatin supplements are essentially concentrated proline and glycine. For most people a normal diet supplies plenty, and the limiting factor for collagen is usually vitamin C, not proline.

Where to get it

Best food sources

Bone broth and gelatin, 1 cup or 1 tbsphigh
Meat, 3 ozhigh
Cheese and dairy, 1 oz or 1 cupmoderate
Eggs, 1 largemoderate
Wheat and soy, 1 cup cookedmoderate

The bottom line

Proline is a self-made collagen building block topped up by protein and collagen-rich foods. Pair it with vitamin C for connective tissue rather than seeking proline alone.

Track proline automatically

Proline is one of the 92 nutrients Vora reads from a photo of your meal, so you can see where you stand without weighing or logging by hand.

Sources and method

The classification, roles, and guidance on this page come from the references below, drawing on the Institute of Medicine (now the National Academies) Dietary Reference Intakes and reputable nutrition science.

  • Institute of Medicine (2005), Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids
  • Linus Pauling Institute, Micronutrient Information Center

This page is for general education, not medical advice. Reference intakes are population averages for healthy people and do not replace guidance from your doctor or a registered dietitian, especially if you are pregnant, managing a health condition, or considering supplements.