Phytosphingosine

What it is

Phytosphingosine is not a ceramide but the backbone half of one. A ceramide is the reaction product of a sphingoid base and a fatty acid, and phytosphingosine is the base that the P stands for in Ceramide NP, AP and EOP. It occurs naturally in the stratum corneum both in free form and as part of the major fraction of ceramides, and it is abundant in plants and fungi, which is where cosmetic supply comes from. On an ingredient list it usually appears beside the ceramides it is related to rather than alone.

How it shows up on a label

What it does well

• Antimicrobial and anti-inflammatory in studies addressing acne

  Laboratory and small clinical work on phytosphingosine reported antimicrobial activity against the bacterium implicated in acne, and improvement when it was used in skin care for the condition. The limitation is worth stating: that work was carried out on a manufacturer's own material and published in a cosmetic-science journal, so it is a starting point rather than an independent confirmation. A separate review of antibiotic resistance lists phytosphingosine among the molecules with little resistance potential being explored for acne.

  Limited evidence

• Drives keratinocyte differentiation in laboratory models

  In human keratinocytes, phytosphingosine activated the PPAR transcription factors that govern barrier maintenance, increased production of the cornified envelope roughly 1.8-fold against controls, raised the differentiation markers involucrin, loricrin and keratin 1, and cut DNA synthesis to a fifth of control levels. These are cell and mouse experiments describing a mechanism, not a measured result on human skin.

  Limited evidence

Worth knowing

• Toxic to cells at high concentrations

  Researchers working on phytosphingosine note that it and its close derivatives show strong toxicity to cells at high concentrations, which is why much of the laboratory work has gone into modified versions intended to keep the activity and lose that effect. This is an observation about concentrated material in culture, well above anything a mask contains, and it is context for reading the literature rather than a caution about the ingredient on a pack.

  Matters most toAnyone reading the primary literature on this ingredient.

• Less settled than the ceramides beside it

  The CIR has assessed several phytosphingosine derivatives, among them caprooyl phytosphingosine, but its ceramides report does not cover the free base, so this ingredient has no safety conclusion of its own from that panel in the way the ceramides listed next to it do. The efficacy literature is small and largely preclinical. Nothing here suggests a problem; there is simply less to go on.

  Matters most toAnyone weighing this ingredient against the better-documented ceramides.

Where the EU stands

Sources (4)

Every link goes to the original: a journal, a PubMed record or an EU document.

1. [1]
   Anti-microbial and -inflammatory activity and efficacy of phytosphingosine: an in vitro and in vivo study addressing acne vulgaris

   International Journal of Cosmetic Science · 2007 · doi:10.1111/j.1467-2494.2007.00378.x

   Reported antimicrobial and anti-inflammatory activity for phytosphingosine in acne, in work carried out on the producer's own material rather than independently.

2. [2]
   Antibiotic resistance to Propionobacterium acnes: worldwide scenario, diagnosis and management

   Expert Review of Anti-infective Therapy · 2015 · doi:10.1586/14787210.2015.1040765

   A review of antibiotic resistance in acne lists phytosphingosine among the novel molecules with little resistance potential, alongside octadecenedioic acid, lauric acid, retapamulin and resveratrol.

3. [3]
   Phytosphingosine stimulates the differentiation of human keratinocytes and inhibits TPA-induced inflammatory epidermal hyperplasia in hairless mouse skin

   Molecular Medicine · 2006 · doi:10.2119/2006-00001.Kim

   Phytosphingosine activated PPAR signalling in keratinocytes, raised differentiation markers and increased cornified envelope production about 1.8-fold against controls.

4. [4]
   Phytosphingosine derivatives ameliorate skin inflammation by inhibiting NF-kappaB and JAK/STAT signaling in keratinocytes and mice

   Journal of Investigative Dermatology · 2014 · doi:10.1038/jid.2013.453

   Records that phytosphingosine and its acetylated derivatives are part of the skin's own defences but show strong toxicity at high concentrations, which is why modified versions were developed.