Polynucleotides

Sodium DNA is fragmented deoxyribonucleic acid, usually derived from salmon or trout milt, prepared as a sodium salt. It is more commonly known in aesthetics as polynucleotides.

What it is not

The name causes reasonable confusion, so worth stating plainly.

These fragments do not enter your cells, do not become part of your genome, and do not alter your DNA in any way. They are short chains of nucleotides that the body breaks down and treats as raw material and as signalling molecules, in much the same way it treats any other biological polymer.

Why fish

Salmon and trout DNA is used because its nucleotide sequence has high homology with human DNA, meaning the building blocks are closely comparable. Fish milt is also an abundant byproduct of an existing industry, and the material is purified to remove proteins that would otherwise cause an immune response.

The proposed mechanism

Two effects are usually described.

Polynucleotides are strongly hydrophilic, forming a gel that holds water within tissue. That much is straightforward physical chemistry.

Biologically, they are proposed to act on fibroblasts, the cells responsible for producing collagen and elastin, through purinergic receptors that respond to nucleotides and their breakdown products. Research in this area has reported effects on fibroblast proliferation and on extracellular matrix production.

Injectable versus topical, which is the important distinction

Polynucleotides have become widely used as an injectable treatment in aesthetics, delivered directly into the dermis. There is a reasonable and growing evidence base there, including work in wound healing and tissue repair as well as cosmetic applications.

Topical application is a different proposition and the evidence does not transfer.

Polynucleotides are large molecules. The stratum corneum is specifically structured to exclude molecules of that size, and whether meaningful quantities of intact polynucleotide reach the dermis from a serum is not established.

This matters because the two are frequently discussed as though they were the same treatment in different formats. They are not. A topical polynucleotide product may well do useful things at the surface, holding water and supporting the barrier. Claiming the benefits demonstrated by injection is a different matter.

Not vegan

Sodium DNA is derived from fish. Worth knowing if that matters to you, and relevant to anyone avoiding animal-derived ingredients on ethical or religious grounds.

Fish allergy

The material is purified to remove proteins, and protein is what drives fish allergy. Residual protein content in cosmetic-grade material is very low. Anyone with a severe fish allergy should still take medical advice before use.