Which ingredients should be kept in or left out of a formula has become a huge conversation in beauty in the past year, with experts hotly debating the merits or issues of individual ingredients in papers and magazines on a near daily basis.

Ammonia is one that’s been called into question. Detractors have suggested it permanently damages hair, while those defending it have said it helps to open the hair cuticle and therefore distribute colour like no other ingredient can.

As with all things beauty, it helps to be informed before you make a decision about whether to continue to use it or to cut it out. Here are some key things about ammonia that may help you to decide.

What does ammonia do?

In short, it helps colour to penetrate the hair shaft. Hair is acidic, and it takes an alkaline like ammonia to lift the cuticle and allow the colour to ‘take.’

But what damage could it be doing?

The issue with ammonia is that it can weaken and irreparably damage the hair. Yes, there’s some degree of damage whatever you do to hair, but repeatedly applying ammonia does definitely compromise it. There’s also a potential issue with ammonia irritating skin, which is why a patch test should always be carried out.

If I choose to avoid ammonia, what are my alternatives?

Innovations are happening in the hair colour world all the time, so don’t worry if you decide that you want to use something else. Try the Schwarzkopf Essensity Color Product Range which is ammonia-free and comes in an impressive 58 shades.

Equally, there are plenty of in-salon keratin treatments now that work wonders on damaged hair, so book in for one of them – and use a hair mask regularly at home – if you want to keep using ammonia but would like to offset some of the damage.

If you want some highlights but would like a hairdresser to ronly apply pre-lightener and colour where absolutely necessary, opt for balayage, which is hand painted and allows for a greater degree of control.