1. Read the INCI list, not the front of the box
UK packaging must carry a full ingredient list in descending order. If biotinoyl tripeptide-1, panthenol or biotin appear right at the end, after the preservatives, there is very little of them in the tube. Scan for the letters prost. Isopropyl cloprostenate, ethyl tafluprostamide, ethylcloprostenolamide, norbimatoprost, dehydrolatanoprost and bimatoprost all contain them, and ethyl tafluprostamide and DDDE are two names for the same compound. Brand marketing is no substitute for reading it — twelve of the fifteen products we ranked contain a prostaglandin, several sold on their peptide content and one on being the hormone-free alternative.
2. Match the format to your eyes
Genuinely prostaglandin-free products are rarer than you would think — in our ranking only The Ordinary, Sweed and Eveline qualify once you count natural sources as well as synthetic analogues. They work more slowly, and there is nothing on the label that needs explaining. Conditioners such as RefectoCil and Long4Lashes strengthen what you already have and cost the least per month. Growth serums is where the prostaglandins sit, and it is a bigger group than the marketing suggests — twelve of our fifteen. Watch the names: several brands sell an analogue serum and a peptide-only version under almost the same label, one product marketed as a gentle conditioner turned out to contain DDDE, and one sold as the hormone-free alternative uses a coral extract that is among the richest natural prostaglandin sources known.
3. Work out the cost per month, not the price
A £30 serum that lasts three months costs about £10 a month. A £98 bottle that lasts two costs £49. That gap is far wider than the difference in results. Because lash serums only hold their results while you keep using them, the monthly figure is the one that matters — and it is what we score on.
4. Patch-test, then be patient
Test on the inner forearm for two nights before it goes anywhere near your lash line. Take lenses out before applying and let the serum dry. Then give it time: six to twelve weeks of nightly use is normal before anything is visible in a photograph. Serums promising a transformation in a fortnight are describing mascara.
5. Buy from a UK seller you can trace
Counterfeit lash serums are common on open marketplaces, and a fake tube has no verified ingredient list at all. Buy from the brand's own UK store or an established retailer, check the packaging carries a responsible person address in the UK or EU, and be sceptical of a price far below everyone else's.
