Not all haircare products are created equal—and while many promise to nourish, strengthen, or add shine, some can actually do more harm than good. From hidden harsh ingredients to formulas that strip your scalp of natural oils, the wrong products can lead to breakage, dryness, buildup, or even hair thinning over time.
From trendy hair serums to viral masks, there’s no shortage of products promising healthier, shinier locks. But according to haircare expert and stylist The Blowout Professor, some of the most popular items on shelves might be doing more harm than good. In a recent video, he revealed the eight worst hair haircare products to avoid—and exactly why they could ‘ruin’ your strands. Here’s what to know before your next wash day.
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1. Redken Quick Blowout Spray
This heat-styling shortcut may do the exact opposite of what you want. “The hair on the very top layer dries way faster than the hair underneath it… What that does is cause a ton of heat damage to the top of the section,” he explains. “That’s exactly the part of your hair that takes the brunt of damage from the sun and styling. This product just makes it worse.”
Why it ruins your hair: Uneven drying forces you to overheat the top layers, causing premature breakage and thinning.
2. Olaplex No. 7 Bonding Oil (When Used Incorrectly)
Yes, even a cult favorite like Olaplex can backfire—if you’re using the wrong version for your hair type.
“A client thought she had fine hair, but she actually had coarse hair… Coarse hair needs loads of heavy oil,” he says. “If you use fine-hair oil on coarse hair, it won’t moisturize at all. And if you use coarse-hair oil on fine hair, it’ll feel greasy.”
Why it ruins your hair: Using an oil that doesn’t match your texture can leave hair dry, split, or oily and weighed down.
3. Serums
It might look like a nourishing miracle in a bottle—but don’t be fooled.
“Serums are actually a specialty product. You are not supposed to rely on them to get healthy hair,” he warns. “Serums just coat the hair to make it look shiny. They don’t actually nourish it like oils do.”
Why it ruins your hair: Serums mask damage instead of fixing it, leading to brittle strands long-term.
4. Bonding Intensive Pre-Shampoo Treatments
This one’s a frequent impulse buy for anyone worried about damage—but it may be completely unnecessary.
“If you don’t lighten your hair or do chemical treatments, your hair does not need repair products,” he says. “Air-dried hair might look dull and frizzy, but that doesn’t mean it’s damaged.”
Why it ruins your hair: Overuse of heavy bond-repair treatments on healthy hair can lead to buildup, dryness, and false diagnosis of damage.
5. Clarifying Shampoos (Used Monthly)
The once-a-month clarifying shampoo rule? He calls it flat-out wrong.
“Some stylists say this because they’ve kind of given up on their clients,” he says. “There’s no way to get your hair clean only once a month. Especially not fine hair—it gets oily fast.”
Why it ruins your hair: Infrequent clarifying leads to product buildup, limp roots, and poor absorption of nourishing products.
6. Intense Hydrating Mask
It may sound like a savior for dry hair—but looks can be deceiving.
“Looking at these, you’d think the intense hydration would have more moisture—but it doesn’t,” he explains. “The weightless version actually restores more moisture, even though it’s lighter.”
Why it ruins your hair: Choosing a heavier mask doesn’t guarantee better hydration—and may leave hair dull and weighed down.
7. All Soft Shampoo (When Used Alone)
This beloved shampoo gets credit it may not deserve.
“People try All Soft and think it’s amazing because it has oil in it. But oil in shampoo isn’t nearly as good,” he explains. “You want your oil separately so you control how much and where it goes.”
Why it ruins your hair: Oil in shampoo can coat your scalp, leading to grease, overwashing, and stripped moisture.
8. Always Relying on Serums Instead of Oils
It’s a common mistake—and one of the most misleading habits in modern hair haircare.
“Serums aren’t even on my chart. That’s because good oils now contain serum ingredients. You get the best of both worlds,” he says. “Serums are completely unnecessary if you’re using the right oil.”
Why it ruins your hair: Serums offer superficial shine but no deep hydration—leaving dry hair untreated beneath the gloss.
