7 best nail supplements that actually work, tested by 160 people

We’ve been testing products for over 100 years at the Good Housekeeping Institute, so we have a lot of testing experience and know-how to fall back on. From the best collagen supplements to the best retinol and hair growth serums, our team of experts rigorously test each product against its claims.

Our beauty tester, Juliet Heaton, has a master’s degree in cosmetic science and has led our skincare, makeup and haircare testing for over two years. For the nail supplement category, she analysed each product’s ingredients lists, checking their makeup could actually deliver on their claims. She then sent samples of each product out to our testing panel to review for 12 weeks before giving detailed feedback on how effective they were.

Our lifestyle writer, Madeleine Evans, then analysed all the data and feedback, writing up the pros and cons of each product, informed by our panellists’ experiences and results.

What vitamins help strengthen nails?

It’s helpful to know what vitamins and minerals you may be lacking, so you can try incorporating more of them into your diet.

If your nails keep splitting, you could be low on iron, biotin, collagen and vitamins A and C. These nutrients build up nail strength and maintain growth at a normal level.

If you notice white spots on your nails, you’re likely not getting enough zinc or calcium, used for cell production and bone strength respectively.

Do nail vitamins really work?

Despite the enthusiastic claims made by marketing teams, bloggers and Instagram influencers, nail supplements aren’t regulated by an independent medical body. This can make it tricky to know which brands are genuine and which are overstating claims in a bid for your hard-earned cash.

Put simply, supplements will only make a difference to your nail health if you are already lacking the vitamins they contain. This is because your body can only process and absorb a certain amount of any vitamin.

In many cases, vitamins can help, but it’s important to be clear that supplements aren’t a miracle cure. If your brittle nails are caused by something other than a vitamin deficiency, you're unlikely to notice any change. If in doubt, head to your GP for a quick blood test.

What vitamin am I lacking if my nails are weak?

Dr Amy Vower, NHS GP and hair restoration doctor at Hair GP, explains that a lack of iron can be a common culprit. ‘Low iron can cause brittle or spoon-shaped nails, alongside tiredness and hair shedding,’ she says.

‘However, in most people, weak/brittle nails aren't a vitamin deficiency at all; the most common causes are external things such as frequent hand-washing, water exposure, polish, gels, acrylics and simple ageing,’ she adds.

What’s the best time to take nail supplements?

‘Timing matters far less than consistency,’ says Dr Amy. So you’re best finding a time when you’re most likely to remember to take them consistently, whether it’s at breakfast or in the evening.

‘If you take them with food, then it can reduce the chance of nausea and help absorb fat-soluble vitamins, like vitamin D. Supplements that are water soluble can be taken at any time of day,’ she explains.

‘If your supplement contains iron, then avoid taking it with any caffeine or dairy products (or replacements like oat or soy milk), as these can block the iron absorption.’