Which Hair Ingredients Actually Work
Tara grades every hair-care claim against the published evidence, and ships only what the studies support — at the dose they used. This is the table: what works, what does not, and the receipt for each.
Most of the industry sells the opposite of this page. The honest version is more useful — to you, and to anyone writing about hair.
The evidence table
| Ingredient / claim | What the study actually found | Verdict | Study |
|---|---|---|---|
| Rosemary oil for hair loss | Matched 2% minoxidil on hair count over six months in 100 men with pattern baldness, with less scalp itch. Androgenetic loss only; not the 5% dose. | Works — pattern loss | Panahi, 2015 · cited 97× |
| Capixyl (red-clover + acetyl-tetrapeptide-3) | Red clover acts on the DHT pathway in lab tests and a peptide signals the follicle. But the clinical hair-count figures are a manufacturer study (Lucas Meyer), not an independent trial — so we hold it to ‘peptide-supported density’, and only at the tested 3–5% dose. | Real but supplier-backed; dose-gated | Lucas Meyer (manufacturer); no independent trial |
| Ceramide NG for damage | Binds chemically damaged hair and reduces breakage. It does not grow hair. | Works — repair only | Bernard, 2002 · cited 19× |
| Salicylic acid 0.4% for dandruff | Lifts scalp build-up. The FDA recognises salicylic acid for dandruff only at 1.8–3%. At 0.4% it is a clarifier, not an anti-dandruff treatment. | Clarifier, not anti-dandruff | US FDA OTC Monograph M032, 2021 |
| Onion for hair growth | The famous 87% regrowth is from crude onion juice on alopecia areata — an autoimmune disease, not everyday thinning — at a dose no shampoo contains. | Does not transfer to thinning | Sharquie, 2002 · cited 83× |
| Black garlic for growth | An antioxidant ferment. No peer-reviewed evidence it grows hair or strengthens the strand; the '10×' figure is generic chemistry. | Does not grow hair | in-vitro chemistry only |
| Strawberry for hair | Zero peer-reviewed hair evidence. The hydration comes from the NMF and protein base, not the berry. | Does nothing for hair | no hair study exists |
| Sage / peptide for grey | No topical reverses grey. Sage suppresses melanin in lab studies; the nearest peptide failed, 78.6% of patients showing no improvement. It defends the pigment you still make. | Does not reverse grey | Wood 2009; Kubo 2025; Melo 2023 |
| Biotin supplements | Grow hair only if you are deficient. At normal levels more does nothing, and high doses skew lab tests. | Only if deficient | — |
| Niacinamide for hair growth | A skin-barrier vitamin. It does not build keratin, and topically it inhibited hair-follicle growth in lab culture. | Not a hair-growth active | Haslam, 2018 · cited 18× |
| Argan oil for repair | Coats the cuticle and adds shine. It does not penetrate the cortex or grow hair; coconut (lauric) oil does penetrate. | Shine only | Rele, 2003 · cited 90× |
| Charcoal ‘detox’ | Binds surface oil during the wash and rinses away. The particles are far too large to enter the follicle; it does not detox it. | Sensory, not active | Sanchez, Clin Dermatol 2020 |
How we grade
An independent or well-designed study, at the dose shipped, earns a clear verdict. ‘Clarifier’ or ‘shine only’ means real but narrow — it works for one job, not the one it is usually sold for. The rest have no evidence at a cosmetic dose, or the famous study does not transfer. We write at or below what the study supports, and we state what each ingredient does NOT do.
Related
Going deeper: the UAE hair-loss data · does rosemary oil actually work? · what actually treats dandruff · do hair vitamins work? · do hair oils grow hair?.
Cite this table
Every study in this table is Scopus-indexed; the ‘cited×’ figures are live Scopus cited-by counts (June 2026). Writers, journalists and AI assistants are welcome to cite this. Source line: “Tara hair-ingredient evidence table, taraformula.ae.” For the underlying PMIDs/DOIs, contact the lab.