Hair Theory Lab
Hair Theory Lab Serum-in Oil, 95ml
Hair Theory Lab Serum-in Oil, 95ml
Hair awakens to the miracle of light. A restorative oil that reaches the five layers of the cuticle.
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• Authenticity guaranteed.
• Ships direct from Japan in 3-5 days
• Custom duties & tariffs fully handled by us for US customers.
• Track your order via USPS, Royal Mail, Canada Post, Australia Post.
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What it is
[01. Reinforcing each of the 5 layers of the cuticle] (1) Epicuticle layer "Glossy film coating (18-MEA & rice protein*1)": Reconstructs a hydrophobic barrier on the hair surface, protecting shine and manageability. (2) Layer A "Heat-reactive repair (γ-docosalactone*2)": Repairs lifted cuticles with the power of heat, making hair manageable for longer. (3) Exocuticle layer "Moisture veil component (polyquaternium-64*3)": A cationic film locks in moisture at the ends of the hair, leaving it soft and smooth. (4) Endocuticle layer "Lamellar shield (polyquaternium-61)": A nanolamellar layer evenly repairs dry cuticles, increasing adhesion. (5) Inner layer (CMC repair layer) "Ceramide booster (Quaternium-33, 18 & 3 types of ceramides*4)": Reinforces CMC to boost strength and elasticity from within. [02. Light-reflecting formula that creates an angelic halo] The five layers of cuticle are aligned to reflect light evenly and smooth the hair surface. The "angelic halo" reflects light and moves on its own with every movement. [03. Airy texture that provides amazing manageability] A unique golden ratio that is not too heavy but provides firm hold, achieving both lightness and manageability. For a smooth, gliding finish. [04. Heat protect formula] Contains ingredients that protect the cuticle using the heat of a hairdryer. Drying locks in the repair ingredients inside. *1 Cetearamid ethyldiethonium hydrolyzed rice protein (hair conditioning ingredient) *2 Hair conditioning ingredient *3 Hair conditioning ingredient *4 Ceramide AP, Ceramide NG, Ceramide NP (moisturizing ingredients)
Ingredients
How to use
After towel-drying or applying hair milk, apply an appropriate amount to damp hair. It can also be used as a styling product.
We ship internationally from Japan!
Frequently Asked Questions
Are the products you sell authentic?
Authenticity is 100% guaranteed. We source directly from the brand, or from official stores within Japan.
All products are fresh off the shelves and never outdated.
What are your shipping rates?
On orders under US$75, shipping is a flat US$20 to the United States and US$10 to all other countries.
Orders of US$75 or more ship free, applied automatically at checkout. Your exact shipping cost is shown before you pay.
How long does delivery take?
These estimates are for International Airmail (Tracked) and include 3 to 5 business days of processing in Japan.
- United States: 12 to 15 business days
- Canada, United Kingdom, France, Germany: 9 to 12 business days
- Australia, New Zealand, Denmark, Finland, India, Indonesia, Italy, Netherlands, Spain, Sweden, Switzerland: 10 to 13 business days
- China, Hong Kong, Malaysia, Singapore, South Korea, Taiwan, Thailand, Vietnam: 8 to 10 business days
- Rest of the world: 11 to 18 business days
Actual delivery can be affected by customs clearance, seasonal congestion, or carrier delays in the destination country, all of which are outside our control.
Do you offer express shipping?
Yes. As of 22 July 2026, we offer International Express Mail through Japan Post. The cost is based on order weight and is calculated automatically at checkout.
Will I pay customs or import fees?
US orders: No. As of July 1, 2026, all US orders ship DDP (duties delivered prepaid), meaning we prepay all import duties on our end. Nothing is due at your door.
Orders outside the US: Possibly. Duties and import taxes are set by your local customs authority and are not collected at checkout, so any charges on delivery are your responsibility.
We're working on rolling out prepaid duties for more countries soon.