Peptides

Tetrapeptide-21

Reviewed by Emma · Last updated 18 Aug 2026

Also known as: SpecPed® SC-Tetra21

Signal peptide for collagen and hyaluronic acid

Best For Skin Types

All

Addresses

ageing, loss of firmness, dehydration, fine lines

What Is Tetrapeptide-21?

Tetrapeptide-21 is a four-amino-acid peptide that acts as a signal to stimulate the production of both collagen and hyaluronic acid in the skin. This dual action addresses both structural firmness and hydration simultaneously.

By boosting the skin's natural production of these essential components, this peptide helps restore a more youthful, plump appearance while improving skin resilience and elasticity.

How It Works

Tetrapeptide-21 is a synthetic peptide made up of the amino acids glutamic acid, glycine, and lysine. The sequence was derived from extra cellular matrix (ECM) proteins. It acts as a signal peptide to fool the skin into thinking it has to repair and regenerate ECM proteins. When combined with butylene glycol, glycerin, and water, it is known by the trade name SpecPed® SC-Tetra21. The manufacturer of SpecPed® SC-Tetra21 claims it helps prevent wrinkles and other signs of ageing by boosting proteins in skin’s extracellular matrix. It’s said to also boost skin’s architectural scaffolding as well as its hyaluronic acid content, which should have a visible impact on skin texture and resilience. The recommended usage level for tetrapeptide-21 is between 0.5-5%.

Clinical Evidence & References

References:

  • UL Prospector, Website, Accessed February 2025 View Study
  • European Commission, Website, Accessed February 2025 View Study
  • Current Protein and Peptide Science, Oct 2021, pages 716 – 728
  • European Journal of Pharmaceutical Sciences, November 2018, Pages 137-144
  • Cosmetics, May 2017, pages 1-14

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