Weak and brittle nails: causes and what helps

Most weak, brittle nails are not a sign of a deficiency or a disease. They are what happens when nails dry out and take repeated knocks — washing up without gloves, cleaning products, alcohol hand gel, gel manicures peeled off at home. The single most effective change is also the dullest: protect your hands. Give it two to three weeks of gloves and hand cream and you will usually see a difference.

That said, not every case is ordinary wear and tear. A minority of brittle nails do reflect what the body is or is not getting, and some need a conversation with a doctor or pharmacist rather than another hand cream. This page separates the two, honestly.

Why do nails go weak? The everyday causes, most common first

Start with water and detergent. Washing up without gloves, cleaning the bathroom without gloves, and using alcohol-based hand sanitiser over and over all strip oils from the nail plate and the skin around it. Nails absorb water and swell, then dry and shrink; do that several times a day and the surface starts to flake and split. This is the most common driver by a wide margin.

Then there is mechanical trauma. If you have ever pulled off a gel nail at home, you know exactly what that does to the top layers of the nail. Picking, tapping, using your nails as tools to open cans or scrape labels — all of it counts. So does filing back and forth rather than in one direction, and aggressive buffing.

Diet comes into the conversation, but with more nuance than it usually gets. A very unbalanced diet, low in several nutrients at once, can show up in skin, hair and nails. Micronutrient deficiencies — biotin included — are known to be able to cause changes in the skin, hair and nails. That is not the same as saying that taking extra biotin fixes brittle nails in someone who already eats well. It does not follow, and the evidence does not support it.

What about stress and screen time? There is no evidence in the information available to us that links stress or hours at a computer directly to brittle nails. If someone tells you your nails split because of your laptop, be sceptical. It sounds plausible and it is not established.

What you can change this week, and how long to give it

Begin with the measures that carry the most impact for the least cost. Wear gloves for washing up, for cleaning and for anything involving detergents. They do not need to be clinical gloves; any pair of rubber gloves will do. Do this consistently for two to three weeks, then compare your nails with how they were.

Moisturise your hands and nails after every contact with water. You do not need expensive products or nail-specific treatments. Consistency matters more than the formula. Keep a hand cream next to the sink and use it — that is the whole intervention.

Keep nails short while they are fragile. File in one direction only, never in a sawing motion, and avoid very coarse files. If you wear gel polish, take a break of a few weeks and have it removed in a salon rather than at home.

Look at your plate. You do not need a special diet. You need to eat varied meals across the day, with enough protein, vegetables, fruit and good-quality fat. A balanced diet is the base; supplements do not replace that base.

What tends not to help, even though everyone recommends it

Plenty of advice about nails circulates with less evidence behind it than people assume. It is worth being blunt about that.

• Taking high-dose biotin for no particular reason. In healthy people, the idea that biotin supplementation improves hair and nails is not supported. Reviews note that individuals with normal levels generally do not benefit.
• Nail hardeners containing formaldehyde, or very astringent products.
• Soaking nails in olive oil, milk or lemon juice. It sounds like a grandmother's remedy, and that is what it is: there is no reason to expect results.
• Buying "hair and nail" supplements without reading the label. Many combine high doses of several vitamins, and more is not always better.

None of this means those gestures are dangerous. It means they cost time and money without addressing what is actually breaking the nail.

Where supplements honestly fit

This is the part that deserves care. The evidence on biotin and nails is emerging, not settled. A systematic review of 18 studies found that biotin supplementation improved hair and nail growth in people with poor biotin status, but the evidence in healthy individuals is limited. In plain terms: if you have a deficiency, supplementation may make a difference; if you do not, it probably will not.

Biotin is a water-soluble vitamin that acts as a coenzyme in several metabolic pathways. Deficiency is rare, but real: micronutrient deficiencies, biotin among them, can cause changes in the skin, hair and nails. That is the honest boundary of the claim, and biotin contributes to the maintenance of normal hair and skin — which is not the same as repairing a broken nail.

There is also a practical point many people never hear. Overuse of supplemental biotin may interfere with laboratory tests that rely on biotin-based immunoassays. If you have blood tests regularly, or if you are investigating a health complaint, it is worth telling your doctor and the laboratory that you take a biotin supplement. It is a simple piece of information that avoids confusing results.

If, after reviewing your routine and your diet, you want to consider a supplement, one option in gummy form is Hair & Nails Gummies from TuttiBear, intended for adults, with biotin among the ingredients. The directions are to chew 2 gummies per day, preferably after a meal. Do not exceed the recommended daily dose. Food supplements should not be used as a substitute for a varied and balanced diet and a healthy lifestyle. Keep out of reach of children. In case of pregnancy, breastfeeding, illness or use of medication, consult a healthcare professional before use. Contains polyols; excessive consumption may produce laxative effects. And remember: biotin may interfere with the results of some laboratory tests, so inform your doctor and the laboratory before having them done.

Those are the authorised statements, and that is as far as it goes. There is no promise here of new nails.

When weak nails stop being an ordinary problem

There are situations where it is worth stopping the self-help and speaking to a doctor or pharmacist. These are the ones that matter:

• One nail changes and the others do not — discolouration, a dark streak, thickening or separation from the nail bed.
• Pain, swelling, redness or discharge around the nail, which may suggest infection.
• Changes in several nails alongside other symptoms — fatigue, hair loss, skin changes, unexplained weight change.
• Nails that have become brittle suddenly, or that split and crumble despite weeks of protecting your hands.
• You are pregnant, breastfeeding, taking medication or managing a long-term condition and are considering a supplement.

None of this is meant to alarm you. It is meant to separate the ordinary case — nails that break because of dryness and use — from the case that deserves an appointment. If you are unsure, the pharmacist is a good first place to ask, no booking needed.

How long before you know whether it is working

Give routine changes at least two to three months before you judge them. Nails grow slowly, and the part you see today was formed weeks ago; a fortnight of gloves will not transform a nail that is already split. If after that time nothing has changed, or things have got worse, then the problem probably was not only the washing-up liquid — and it is worth investigating other causes with a professional.

What to do now: buy a pair of gloves, put a hand cream beside the sink, cut your nails short and give the gel a rest. Then wait. The hard part is not knowing what to do; it is keeping it up long enough to see the difference.