No. 0.5 Scalp Longevity Treatment - Traitement cuir chevelu

Great product

I was recommended by my sister regarding this product and I’m glad I trusted her recommendation. No more dryness on my scalp. Just what the doctor ordered!

Feels great on my scalp

One of the biggest strengths of this treatment is its focus on scalp health as the foundation of hair health. Many products prioritize shine or softness of the hair itself, but OLAPLEX No. 0.5 shifts attention to the environment where hair grows. With continued use, the scalp feels more balanced—less dry, less irritated, and noticeably calmer. For those who struggle with itchiness or tightness, this can be a significant improvement. It doesn’t feel like a harsh or medicated solution; instead, it works gradually to restore comfort.

WORKS— BUT AT WHAT COST???

Take my word on this as someone who normally doesn’t mind conventionally “bad” smells…. this product smells awful. The scent is a bizarre mix of acrylic paint and a musty, almost geriatric odor, and the worst part is that it lingers for nearly 24 hours. It’s not a quick “apply and it fades” situation… it sticks around. You can try to mask it with nice-smelling oils, but since this product is only effective if you’re using it daily or every other day, the trade-off just isn’t worth it. You basically end up walking around with the faint smell of this stuff on a consistent basis. Even if you’re single, imagine this: someone you find attractive accidentally getting a whiff of your scalp with this in… Your hair is actually freshly washed, completely clean… but because you applied this serum, it smells like acrylic paint and nursing home air. Completely unacceptable in 2026. In my experience, I’ve gotten the same — if not better — results with minoxidil, so I won’t be repurchasing this. I’m going to try a peptide serum instead for hydration. I want to add that the bottle is tiny for the price, and considering the awful smell and the amount you get, it’s simply not worth it. This formulation honestly feels lazy. Simply unacceptable.

horrible smell

smells horrible!!!! worst smelling product like stale eggs and rotting fruit.

Smells Awful

it wreaks! put my cat on edge trying to figure out the disturbing smell, as well as myself. I thought mine had gone bad until I read the other reviews. smells absolutely awful.

Invest in your haircare

I have been using for over six months… my hair is stronger. Excellent for menopause women’s and hair coloring ! Good investment

Intolerable smell

This product smells awful. Like the yeast byproducts of making beer or worse. I literally couldn’t sleep after trying it for an overnight treatment, it was that strong and that bad. I was really stunned because everything else I’ve tried from Olaplex has a pretty mild pleasant/neutral scent (No. 3, 4, 5, 5 leave-in, 6, 7, 8, 9). Returning this; even if it somehow provides good benefit to the scalp there is no way I could tolerate that smell ever again. The bottle even suggests you could use it as part of your styling routine— go out in public after applying that?! Absolutely not. Anyway, I do not normally write reviews but I wanted to provide this PSA to y’all— do not waste your money on this one. Will stick with my other Olaplex faves; I do highly recommend No. 4, 5, 5 leave-in, 7, and 9.

Not recommended if you have sensitive scalp

I wouldn’t buy this again. It gave me a very dry and itchy scalp. I was using it a couple of times so my skin got used to it, but it got worse :(. I had to stop using it all together and wasted my 40 dollars

Why this smell so bad as a old cheese. It's my first time using this but for this price unless should smell a little bit better

Pleased

I bought this product when it first came out. I use it once a week, the night before I wash my hair. I have noticed there is less hair in my drain after washing my hair. Also noticed more little hair growths. Only downsize is the product smell. It is not a pleasant smell.

Odeur

Odeur horrible je n'arrive pas à passer outre

Scalp treatment

Great product. Very soothing on my scalp. Does not leave my hair looking or feeling oily.