Reference

Lash science, defined

The peptide and lash-biology terms you will meet across these pages and our labels, in plain language and without the marketing.

Anagen phase: The active phase of the lash growth cycle, when the follicle is producing a new lash and the fibre lengthens. Eyelashes have a comparatively short anagen phase, roughly four to six weeks in most published estimates, which is one reason lashes stay much shorter than the hair on your head.
Appearance-based claim: A statement about how lashes look rather than about a change to the body, for example “lashes appear fuller” instead of “grows lashes”. Cosmetic products in Australia, the EU, the UK and the US must keep their claims appearance-based, and every RUSKI product claim is written this way by design.
Bimatoprost: A prostaglandin analogue first developed as a glaucoma medicine and later approved in some markets as a prescription treatment for sparse lashes. It is a therapeutic drug rather than a cosmetic ingredient, and is associated with side effects such as iris colour change and loss of orbital fat around the eye. RUSKI serums are formulated without it.
Biotin: Also known as vitamin B7, biotin is a nutrient often included in lash and hair products as a conditioning ingredient. Oral biotin only makes a measurable difference in genuine deficiency, and robust evidence that biotin applied topically changes lash appearance is limited, a limitation RUSKI states plainly rather than glossing over.
Biotinoyl Tripeptide-1: An INCI-named peptide that links biotin to a short three-amino-acid chain, used as a conditioning active in lash and hair formulations. It is the peptide behind Croda Widelash and also appears in complexes such as Procapil. Most of the supporting evidence comes from scalp-hair studies rather than lashes specifically, so lash-specific data is limited.
Carrier peptide: A family of cosmetic peptides that carry trace elements, often copper, to help stabilise or deliver them within a formulation. Carrier peptides are one of the peptide types used in skin and hair care; signal peptides are another.
Catagen phase: The brief transitional phase of the lash growth cycle, sitting between active growth and rest, when the follicle stops producing new lash material and begins to shrink. It typically lasts only a couple of weeks.
Cosmetic vs therapeutic claim: A cosmetic claim describes cleansing, conditioning or the appearance of lashes; a therapeutic claim describes treating, preventing or physically changing the body, which moves a product into medicine regulation, the TGA in Australia. Words like “grows” or “repairs” are therapeutic claims, which is why cosmetic lash products cannot make them.
Cyanoacrylate: The fast-setting adhesive chemistry used in professional lash-extension glues to bond each extension to a natural lash. Oil-based products can break these bonds down, which is why extension wearers are advised to choose water-based, oil-free formulas.
Extension-safe: A product described as extension-safe is formulated not to interfere with lash-extension adhesive, generally meaning it is water-based and free of the oils that dissolve cyanoacrylate bonds. Applied to a clean, dry lash line and allowed to dry fully, an extension-safe serum conditions the natural lash without loosening extensions.
Humectant: An ingredient that attracts and holds water, keeping the lash fibre supple and conditioned rather than dry and brittle. Glycerin, panthenol, betaine and sodium hyaluronate are common humectants, and their moisture-binding role is well established in cosmetic science.
Hyaluronic acid / sodium hyaluronate: Hyaluronic acid is a water-binding molecule; sodium hyaluronate is its salt form, which is more stable and used in most formulations. Both act as humectants that hold moisture at the lash line for a conditioned look. The water-binding function is well documented, though lash-specific evidence is limited.
INCI: The International Nomenclature of Cosmetic Ingredients, the standardised naming system used on ingredient lists worldwide, so the same ingredient carries the same name in every country. INCI names can look technical (Sodium Hyaluronate, Myristoyl Pentapeptide-17), but they let you compare products accurately, which is why RUSKI publishes every formula in full INCI form.
Isopropyl cloprostenate: A prostaglandin analogue that appears in some over-the-counter lash serums, at times without being clearly flagged. Like other prostaglandin analogues it is associated with eye-area side effects, and RUSKI serums are formulated without it.
Lash follicle: The small structure in the skin from which an individual lash grows, housing the root of the lash and cycling through growth, transition and rest phases. The follicle is useful for explaining the biology of lashes; note that cosmetic products speak to the appearance of the lash line, not to the follicle itself.
Lash lift: A salon treatment that uses a chemical solution to reshape natural lashes into an upward curl, creating a lifted look for several weeks without extensions. Because the lashes are chemically processed, many people use a conditioning serum afterwards to support the look and feel of their lashes.
Lash shaft: The visible part of the lash, the fibre above the skin, made largely of the protein keratin. Because the shaft is not living tissue, conditioning products work on its surface, smoothing and hydrating the fibre so it looks and feels better rather than altering how it grows.
Myristoyl Pentapeptide-17: An INCI-named conditioning peptide widely used in lash serums (marketed to formulators as SymPeptide XLash), studied for its effect on the measured appearance of lash density. Most of the supporting data is manufacturer consumer-panel testing; independent peer-reviewed evidence in lashes specifically is limited, and RUSKI says so.
Panthenol: Provitamin B5, a humectant and conditioning agent that binds moisture into the lash fibre for a smoother, more flexible surface. Its conditioning role is well documented on hair keratin; direct lash evidence is limited and largely extrapolated from hair science.
Patch test: A small trial of a product on an inconspicuous area of skin, left for a day or two, to check for a reaction before applying it near the eyes. RUSKI recommends a patch test before first use of any lash product, and discontinuing use if irritation occurs.
Peptide: A short chain of amino acids, the building blocks of proteins. In cosmetics, peptides are used as conditioning actives, they are cosmetic ingredients, not medicines, and the honest position is that they can support the appearance of lashes without the drug action of prostaglandin analogues.
Prostaglandin analogue: A class of synthetic compounds related to prostaglandin signalling. Some are used in glaucoma medicines and prescription lash treatments. The class is associated with documented risks including iris pigmentation and changes around the eye; persistence and frequency vary. No prostaglandin analogues appear in the disclosed INCI lists for RUSKI serum formulas.
Signal peptide: A family of cosmetic peptides thought to act as messengers within the skin, used in formulations aimed at the appearance of firmer skin or a fuller-looking hair or lash line, Acetyl Tetrapeptide-3 is one example. Most evidence for lash-line signal peptides comes from supplier studies, often conducted on scalp hair, so lash-specific data is limited.
Telogen phase: The resting phase of the lash growth cycle, when a fully grown lash is no longer active and eventually sheds so a new one can replace it. Because each lash cycles independently, only a portion are shed at any one time, which is normal, and different from unusual lash loss.
Third-party testing: Testing carried out by an independent laboratory rather than the brand itself, so results are not self-reported by the company selling the product. Third-party testing underpins the Ruski Standard: every RUSKI formula is third-party tested, with the report available on request.
Tubing mascara: A mascara that forms flexible polymer “tubes” around each lash rather than a paint-like coat, so it wears without flaking and removes with warm water alone instead of heavy rubbing or oil-based removers. This gentle removal makes tubing formulas popular with extension and lift wearers.