Label Check
Short answers to ingredient questions, "is this safe" questions, myths worth correcting, and cheap fixes that actually work. Each page opens with the question and a one-line answer, then shows the published evidence behind it, linked.
How this differs from reviews. A review means we bought the product and used it for weeks — that is the only thing we will ever call tested. Label Check is desk research: we have not personally used most of what is discussed here, and we say so on every page. We publish it because these questions get asked constantly and the answers on the first page of results are usually written by someone selling the thing. Each answer also carries an evidence rating, which describes the quality of the published data, not our confidence.
No — ophthalmologists advise against putting bottled castor oil in the eye, because it is not sterile, it can blur vision and trigger irritation, and excess oil can block the meibomian glands and make dry eye worse rather than better.
Most scalp crusting comes from one of a handful of things: seborrhoeic dermatitis, scalp psoriasis, folliculitis, an allergic reaction to a hair product, or the scab cycle from scratching and picking. A medicated shampoo is a reasonable first step for mild, itchy, greasy scale — but painful sores, pustules, hair loss, spreading patches, or crust that will not clear in a few weeks need a doctor, because scalp psoriasis and tinea capitis cannot be treated with a drugstore bottle.
An EWG score rates hazard — whether a substance could cause harm at some dose — not risk, which is whether it will cause harm at the amount actually in your product, so a high score tells you an ingredient has been studied and found capable of harm somewhere, not that the bottle in your hand is dangerous.
Partly — Yuka reads an ingredient list correctly, but it scores ingredients in isolation, and because cosmetic formulas rarely disclose concentrations, it cannot judge the dilution, pH or delivery system that actually determine whether a product irritates you.
Slightly, on the evidence that exists. In the one multicentre randomised trial that compared them head to head in severe dandruff, ketoconazole 2% improved total dandruff severity by 73% at week 4 versus 67% for zinc pyrithione 1%, and recurrence after stopping was significantly lower with ketoconazole. Two cautions: the trial tested the 2% strength, which is prescription-only in the US, and Cochrane graded the zinc pyrithione evidence base as very low quality.
The 2004 study everyone remembers found parabens in 20 breast tumour samples with no healthy tissue to compare against, and its own text said no claim was made that parabens caused those cancers — but regulators have still tightened the rules since, banning five longer-chain parabens in the EU and capping propyl- and butylparaben at 0.14%, so the fair summary is restricted rather than exonerated.
Build-up is physical debris — dead skin, sebum and product residue — that a descaling shampoo can wash off. Dandruff is an inflammatory reaction involving Malassezia yeast, and it needs an antifungal like ketoconazole, zinc pyrithione or selenium sulfide. Salicylic acid clears the scale but leaves the yeast, which is why a build-up shampoo alone tends to work for a week and then stop.
Often, yes — while you are actively flaking. Malassezia, the yeast that drives dandruff, cannot synthesise its own fatty acids and lives by breaking down the lipids around it, so adding oil to an inflamed scalp can supply the organism you are trying to reduce. The evidence is not one-sided: a longitudinal scalp microbiome study found coconut oil shifted dandruff scalps toward a healthier commensal profile. The practical rule is sequence, not prohibition — settle a flare with an antifungal first, and if you oil, favour squalane or MCT over coconut oil.
Better not to. Neomycin, one of Neosporin's three antibiotics, is one of the most common contact allergens in patch testing — around 8.7% of tested patients react — and the allergic rash looks so much like a spreading infection that people respond by applying more. For a clean minor scrape, plain petrolatum keeps the wound moist without the allergen.