One of the more under-discussed aspects of skin health is its dependence on dietary protein. The skin is, fundamentally, a protein structure — collagen, elastin, keratin, structural proteins of various types account for the bulk of skin tissue. The amount of protein you eat directly affects what your body has available to maintain and repair that structure.

Most adults eat dramatically less protein than is optimal for skin health. The cost shows up in skin quality, healing rate, and the rate at which skin reflects aging.

The headline numbers

The U.S. RDA for protein (0.8g per kg of bodyweight) was set decades ago, based on minimum-to-prevent-deficiency studies. It's not optimal for adults trying to maintain skin, muscle, or any other protein-dependent tissue.

Modern research consensus for adults over 40, particularly those wanting optimal skin and tissue maintenance:

  • 1.4-1.8g protein per kg of bodyweight per day — substantially higher than the RDA.
  • 30-40g per meal across three meals — even distribution matters.
  • Quality protein — complete amino acid profiles, particularly the amino acids that collagen tissues need.

For an 80kg adult, that's 110-145g of protein daily. Most adults eat 50-70g.

The skin-specific amino acids

Collagen has an unusual amino acid composition, dominated by:

  • Glycine — the smallest amino acid, allows collagen's tight triple-helix structure.
  • Proline — particularly hydroxyproline, unique to collagen.
  • Hydroxyproline — required for collagen stability.
  • Hydroxylysine — for cross-linking.

These amino acids are present in most dietary proteins but are particularly concentrated in:

  • Bone broth and slow-cooked meat
  • Skin-on poultry, skin-on fish
  • Connective tissues, tendons, gelatin
  • Hydrolysed collagen peptides (which is why supplemental collagen specifically supports collagen tissues)

Modern Western diets have largely eliminated these protein sources — the meals our great-grandparents ate routinely (offal, slow-cooked tougher cuts, bone broths, gelatinous stews) are now uncommon.

The practical translation

What this looks like in everyday eating:

Breakfast (30-40g protein)

  • 3-egg omelette with cheese (~25g) + small Greek yogurt (~10g) = 35g
  • Cottage cheese (1 cup, ~28g) + egg on the side (~7g) = 35g
  • Smoked salmon (100g, ~20g) + egg (7g) + Greek yogurt (10g) = 37g

Lunch (35-40g protein)

  • Chicken breast (150g, ~38g) on salad with mixed vegetables
  • Tuna salad (1 can ~25g + cheese 8g) on toast
  • Bone broth (8g) + lean meat (150g, ~30g) in stew

Dinner (35-40g protein)

  • Salmon (150g, ~35g) with vegetables and rice
  • Beef (150g, ~38g) with greens
  • Slow-cooked pork shoulder (150g, ~35g) — bonus collagen-specific amino acids

This pattern reliably hits 100-130g/day. Add a protein-rich snack or shake to push toward the upper range.

The collagen-specific edge

Hydrolysed collagen peptides — supplementally — provide concentrated amino acids biased toward what collagen tissues specifically need. While general protein adequacy is the foundation, supplemental collagen acts as a targeted top-up to the amino acid pool that skin and joint tissues draw from.

This is why both can matter. General protein is the foundation; supplemental collagen is the targeted layer.

What happens when protein is inadequate

Protein-deficient skin shows up in:

  • Slow wound healing
  • Loss of skin elasticity faster than expected for age
  • Hair quality and growth rate decline
  • Nail brittleness
  • Slow recovery from injury or surgery
  • General "thin skin" appearance

None of these is dramatic in any single week. Across years, the cumulative cost is substantial — and largely preventable with adequate dietary protein.

A note on RenuYou

RenuYou's collagen layer works best on top of adequate dietary protein. The supplement provides 2g/day of targeted collagen amino acids — useful, but not a substitute for the 30-40g of complete protein that each main meal should provide. Get the protein right first; the supplement amplifies what's already in place.

The honest summary

Skin is made of protein. The amount of protein you eat is the foundation that everything else — supplements, skincare, lifestyle — builds on. Most adults eat half what they should.

Eat 30-40g per meal. Three times a day. Your skin in 20 years will look meaningfully different from your peers' as a result.