Buy the Garnier Fructis Sleek & Shine Anti-Frizz Hair Serum.

It does the everyday job the Olaplex does, for a quarter of the price, with years of proof behind it.

What was compared

1. Four times the serum for a quarter of the price
Garnier runs about $2.55 per fluid ounce against Olaplex's $10.67, and the bottle is bigger, 5.1oz versus 3oz. For daily smoothing and shine, that price gap buys nothing extra.
2. A track record Olaplex No.9 hasn't earned yet
Garnier holds a 4.6 star rating across over 45,000 reviews built up over years of real use. Olaplex No.9 reviewers are split, some say it left hair drier or did nothing they could feel despite the bond claims.
3. Frizz control that survives a humid day, tested
Garnier is tested to hold frizz up to 72 hours even at 97% humidity, a specific bar Olaplex never states for No.9. Reviewers with coarse or very dry hair also say No.9 alone is not rich enough, leaving thicker hair still frizzy.
4. Fewer chemicals to worry about, proven not promised
Garnier is certified paraben, phthalate and DMDM hydantoin free, Leaping Bunny cruelty-free certified, and ships in a 100% recycled bottle. Olaplex only claims vegan, with no matching certifications listed on its own page.
5. Yes, it protects hotter tools. Skip it anyway.
Olaplex claims heat protection to 450F, a real number Garnier does not print. But most blow dryers and irons never reach that ceiling, and reviewers already use ordinary anti-frizz serums like this one as their heat guard. Unless you flat iron at max heat daily, you will not feel the difference.