How to read a hair product label

A hair care aisle holds two legal categories side by side, and nothing about the packaging separates them. Some of what is on that shelf is a drug. Most of it is a cosmetic. The rules, the claims and the amount of information you get are different in each case.

Telling them apart is the single most useful skill for this category, and it takes one glance.

The three second test: is there a drug facts panel

If a product contains an approved over-the-counter drug active, it must carry a drug facts panel. That panel names the active ingredient and its strength.

A panel means: there is an active with an approved use, a defined concentration range, and pre-cleared wording for what it can claim. Anti-dandruff shampoos are here. So is minoxidil.

No panel means: it is a cosmetic. It may still work, and conditioning agents genuinely improve how hair looks and behaves. But nothing about its claims has been reviewed, and no concentration is disclosed.

This is the same distinction that makes a sunscreen a drug and a moisturiser not, and it is invisible from the front of a pack, where both types use identical photography and identical adjectives.

What you get when it is a drug

Concentration, which is remarkable on a shelf where nothing else has it.

Pyrithione zinc is permitted “0.3 to 2 percent when formulated to be applied and then washed off after brief exposure”. Coal tar is permitted at 0.5 to 5 percent, and its rule goes further: where a coal tar solution or fraction is used, the labelling must state the identity and concentration of that source and the concentration of coal tar in the finished product.

Two numbers, both compulsory, because a 5 percent solution and 5 percent tar are not the same thing.

You also get constrained wording. The labelling regulation prescribes how these products may identify themselves and what they may claim: a “dandruff (insert product form)” statement of identity, and indications limited to relieving or controlling the named conditions.

So when an anti-dandruff shampoo sounds boring, that is the rule working.

What the regulation says about the other shelf

There is one category where FDA has published its view of the claims, and it is worth knowing because it covers a large part of the aisle.

For over-the-counter products sold for external use as hair growers or hair loss prevention, the regulation names the usual ingredients, Biotin and dexpanthenol among them, and concludes: “all labeling claims for OTC hair grower and hair loss prevention drug products for external use are either false, misleading, or unsupported by scientific data”.

Minoxidil is outside that, because it was approved as a drug rather than sold under a claim.

Note the scope. This is about growth claims on topical products. A conditioner that says it reduces breakage is making a different and often defensible claim, because reducing mechanical damage is something conditioning agents demonstrably do.

Reading the cosmetic part

The ingredient list runs in descending order of quantity down to 1 percent. Below that the order is free. So the first four or five names after water tell you what kind of formula you are holding, and the tail tells you very little.

For a shampoo, the first surfactant is the important one. Sodium lauryl sulfate near the top is a strong cleanser; cocamidopropyl betaine or a glucoside at the top is a milder one.

For a conditioner, look at which silicones are present rather than whether any are. Names beginning with cyclo are usually volatile and evaporate. PEG-modified ones such as dimethicone copolyol are usually water-soluble. Plain dimethicone and Amodimethicone are the water-insoluble ones that condition best and need a stronger wash to remove.

That distinction decides whether you need a clarifying shampoo, and it is on the back of every bottle.

Four things a hair label will not tell you

Concentration, unless it is a drug. The active in an anti-dandruff shampoo is stated. The amount of anything in a conditioner is not.

Whether an ingredient is there for its own sake. Octocrylene in sunscreen is often present to stabilise another filter. Hair formulas do the same thing, and the list records substances rather than purposes.

What it will do to your hair. Porosity, density and damage history vary enormously, and no label is written for you specifically.

Whether it will build up. That depends on what you use to wash it, not on the bottle in your hand.

Where to go next

If your question is about curls, the avoid-list and what survives contact with the evidence is on the curly and coily hair page.

If it is about thinning, the drug and cosmetic line is most of the answer, and that is the hair loss page.