Biotin, Zinc, and Selenium: The Real EU Claims Behind “Hair, Skin, and Nails”

“Hair, skin, and nails” is one of the most common supplement categories in the EU market, and almost all of it rests on the same handful of EFSA-authorized claims for three nutrients: biotin, zinc, and selenium. Understanding exactly what each one is authorized to say — and where enforcement has actually caught brands overstepping — is more useful than any general sense of “these ingredients are for beauty.”

What each nutrient is actually authorized to claim

All three follow the same conditional structure as other vitamin and mineral claims: the product must be at least a “source of”the nutrient in question, per the Annex to Regulation (EC) No 1924/2006, before any of the claims below can be used.¹²

Biotin

Authorized claims include “contributes to the maintenance of normal hair,” “normal skin and mucous membranes,” and “normal nails,” among several others covering energy-yielding metabolism, nervous system function, and macronutrient metabolism (Entry IDs 118, 121, 2876, 2877, and related).¹² A secondary compliance source estimates the “source of” threshold at roughly ≥7.5 μg/day, though this should be confirmed against the current Annex XIII nutrient reference values before use.³

Zinc

Authorized claims include “contributes to the maintenance of normal hair” and “normal nails” (Entry ID 412), alongside “normal skin,” DNA synthesis, and several metabolic claims.⁴ The same secondary source estimates roughly ≥1.5 mg/day for the “source of” threshold.³

Selenium

Authorized claims include “contributes to the maintenance of normal hair” and “normal nails” (Entry ID 281), plus thyroid function, immune function, and protection from oxidative stress.¹ Estimated threshold: roughly ≥8.25 μg/day.³

The three together — biotin + zinc + selenium — form such a common combination that it has become the industry-standard hair and nails formula. The reason is precise: each ingredient independently clears its own “source of” threshold, and each independently carries its own authorized hair and nails claim.

Where brands actually get caught

Real enforcement history is more instructive than the claim text itself. In 2019, the UK Advertising Standards Authority upheld a ruling against a hair-supplement brand that had stacked claims for biotin, selenium, zinc, vitamin B6, vitamin B12, and other ingredients into broader assertions than any single authorized claim supports.⁵ The brand's defense — that each ingredient individually carried an authorized claim — did not hold up, because compliance requires using the specific, exact authorized wording for thatnutrient, not combining multiple nutrients' separate authorized claims into a compound marketing statement implying something stronger than any one claim states on its own.⁵

A related trap: proprietary ingredient blends. Multiple EFSA opinions have specifically rejected health claims for named combination products — including one built from keratin, copper, zinc, niacin, pantothenic acid, pyridoxine, and D-biotin submitted for a “maintenance of normal hair” claim, and another combining B-vitamins with pumpkin seed oil for the same purpose.⁶⁷ In both cases, EFSA concluded that a cause-and-effect relationship between the specific combination product and hair maintenance had not been established — even though several of the individual ingredients inside those blends do carry their own authorized claims separately.⁶⁷ An authorized claim belongs to a specific, characterized nutrient at its own condition of use. It does not automatically transfer to a branded blend just because that blend contains the nutrient.

The practical takeaway

For a hair, skin, and nails-positioned formulation, the safest and most defensible claim strategy follows three steps:

1. Confirm each nutrient — biotin, zinc, selenium — individually clears its own “source of” threshold in the actual formulation, verified against the current Annex XIII NRV table.
2. Use each nutrient's specific authorized claim wording — not a combined or paraphrased version implying a broader effect across all three nutrients together.
3. If the product is marketed under a branded blend name, ensure that name and its marketing do not imply the blend itself has a substantiated effect beyond what its individual authorized-claim nutrients state.