Ever wondered what rules professional stylist live by when it comes to hair health? We chatted to an expert in the industry about her haircare no-nos.

Renee Vallender is the founder of The Straightening Salon, created from her own search for a fuss-free hair solution. As a first-time mum with little time to spare and a head of frizzy “Hagrid hair,” she discovered the power of permanent straightening – and never looked back. Thirteen years on, what started as a personal fix has grown into a business dedicated to helping other women feel confident, save time and enjoy smooth, easy-to-manage hair every day.

As someone who’s spent years both in and behind the chair helping women to tame their unruly hair, I’ve learnt the value of products that truly work and the damage caused by those that don’t.

Here are five things I’d never put on my own hair and that I always recommend my clients avoid too:

Shampoos containing sulphates

Sulphates like sodium lauryl sulphate (SLS) and sodium laureth sulphate (SLES) are detergents that strip away your hair’s natural oils. Yes, they make shampoo foam up beautifully, but they can also leave hair dry and brittle, disrupt your scalp’s natural microbiome and damage hair follicles over time.

At my salon, this is our number-one ingredient to avoid, because sulphates can quickly strip away the results of smoothing and straightening treatments.

I only use sulphate-free shampoos because they still cleanse effectively but leave hair softer, more hydrated and healthier overall.

Heavy, non-water-soluble silicones

Not all silicones are necessarily bad, but heavy, non-water-soluble ones like dimethicone or amodimethicone can build up on the hair, creating a surface shine while suffocating the strand underneath.

Over time, silicones can lock moisture out, leaving hair dry and dull. So reach for products with water-soluble silicones or else avoid them altogether.

Synthetic fragrances

Many synthetic fragrances contain phthalates and parabens, which may irritate the scalp and act as hormone disruptors. Instead, I choose products labelled “phthalate-free” and “paraben-free.”

You can still enjoy a beautiful fragrance, just make sure it’s formulated to be non-toxic and safe. This applies not only to haircare, but to body washes, perfumes and other fragranced products you use often.

Excessive dry shampoo

Dry shampoo can be a life-saver between wash days, but overuse can clog hair follicles and irritate the scalp. It can also lead to a build-up that slows down your hair growth, causes flaking and leaves locks looking dull.

I limit dry shampoo use to one or two days max before a full cleanse. It’s enough to refresh without sacrificing scalp and hair health.

“Miracle” oils that only coat the hair

If an oil contains non-water-soluble silicones, it’s likely just coating your hair for instant shine without actually nourishing it. Over time, this prevents real hydration from penetrating the hair shaft.

That said, not all silicones are the enemy, and when paired with nourishing oils, a volatile silicone like cyclopentasiloxane can actually help. It spreads the “good stuff” evenly throughout the hair, then evaporates without causing buildup.

I also steer clear of pantry oils like coconut or olive oil, which can be heavy and difficult to wash out.

One of the most important parts of hair care isn’t just what you use, but what you avoid. By steering clear of the nasties mentioned above, you’ll help keep your hair healthier and stronger in the long run. Your strands (and your scalp) will thank you for it.

Have you ever learnt the hard way what NOT to use on your hair? Let us know below!