How red light triggers collagen production at the cellular level.

Collagen production peaks in your early 20s and declines roughly 1% per year afterwards. Most anti-ageing skincare addresses that decline from the outside — retinoids exfoliate, peptides mimic collagen fragments, hyaluronic acid plumps water content at the surface. Red light does something different. It doesn't sit on the skin. It reaches the cells that actually make collagen, and it tells them to make more of it.

Collagen and elastin aren't synthesised in your outer skin layer. They're made in the dermis — 1.5 to 3mm beneath the surface — by specialised cells called fibroblasts. Topical creams barely reach them. Most active ingredients, however promising on the label, stop in the epidermis or sit on top of it. Only a handful of interventions reach the fibroblast: ablative lasers, microneedling, retinoic acid in its most potent forms, and red light at 660nm. Of those four, only one is non-invasive, painless, and available as a 10-minute home treatment.

When 660nm photons reach fibroblasts, they're absorbed by cytochrome c oxidase in the mitochondria. Within minutes, ATP output rises 25–40%. Over the following 48–72 hours, the genes coding for Type I and Type III procollagen upregulate. New collagen fibrils are synthesised, cross-linked, and deposited into the extracellular matrix. Repeat the process 4–5 times per week for 8–12 weeks and you get measurable increases in dermal collagen density — with no downtime, no inflammation, and no need for your skin to heal from an injury first.

A 2017 controlled trial in the British Journal of Dermatology measured the effect of daily 10-minute 660nm LED sessions on fine-line depth over 12 weeks. At the 12-week mark, participants showed statistically significant reductions in fine-line depth and surface roughness, and punch biopsies confirmed increased dermal collagen density versus baseline. The effect persisted through a 12-week follow-up period after sessions ceased — suggesting the new collagen was structurally integrated, not a transient response.