B12 BASE THINNER Vitamin Pearl Serum

ONE/SIZE B12 Base Thinner is two products in one bottle: a pearlescent mixing medium you drop into foundation, and a skincare serum you can wear on its own. ONE/SIZE describes vegan crushed pearls that create instant luminosity, backed by a conditioning base of vitamins, hydrators and ceramides. It is oil-free and, per the brand, will not clog pores.

Use as	Foundation mixer or standalone serum
Finish	Pearlescent, luminous
Vitamins	B12 · C · E
Hydrators	Beta glucan · hyaluronic acid
Barrier support	Ceramides · adenosine
Callouts	Oil-free · vegan · gluten-free · cruelty-free

What it actually does

• Thins out heavy foundation. Mixed into a liquid or cream base it dilutes the coverage, so a full-coverage foundation can be dialled down to whatever sheerness you want.
• Adds light to the finish. The vegan crushed pearls are what give the mix its luminosity — glow built into the base rather than dusted on afterwards.
• Extends makeup wear. ONE/SIZE credits the fortifying ingredients with keeping makeup in place longer than it would sit on bare skin.
• Vitamins B12, C and E. The brand lists these as conditioning the skin and defending against environmental stress.
• Beta glucan and hyaluronic acid. Named by ONE/SIZE for delivering intense hydration toward plumper, bouncier-looking skin.
• Ceramides plus adenosine. The brand positions these as limiting moisture loss and softening the appearance of lines and wrinkles.
• Oil-free and non-pore-clogging. Stated by the brand, which matters when you are mixing something extra into a base you wear all day.

ONE/SIZE reports that all testers in its study agreed the serum transforms cream and liquid formulas and adds natural luminosity to makeup. Self-reported results from the brand's own testing; individual experience varies.

Formulated without parabens, formaldehydes and formaldehyde-releasing agents, phthalates, mineral oil, retinyl palmitate, oxybenzone, coal tar, hydroquinone, SLS and SLES sulfates, triclocarban and triclosan, with under one percent synthetic fragrance.

How to use

1. As a mixer: add a little to your liquid or cream complexion product on the back of your hand and blend before applying.
2. Add more to push the coverage sheerer; add less if you only want the glow and not the dilution.
3. On bare skin: wear it alone for immediate radiance, hydration and dimension.
4. Take it past the jawline — the brand suggests the décolletage and anywhere else you want light.
5. Use it daily if you are after the longer-term claims: softer-looking lines and brighter skin over time.

Is it right for you?

Questions

Is it makeup or skincare?

Both, which is the point. ONE/SIZE built it as a mixing medium that also functions as a serum, so it works inside your foundation or directly on clean skin.

How much should I mix in?

Start small and build. The more you add, the sheerer the coverage becomes — so adjust until the base looks the way you want rather than following a fixed ratio.

Will it break me out?

The brand states the formula is oil-free and does not clog pores. As with anything new, patch test on the jaw for a few days if your skin is reactive.

How long does delivery take?

Delivery takes 3 to 21 working days, depending on availability. In-stock items reach you faster; items ordered in for you sit at the longer end. Working days exclude weekends and official holidays.

Which payment methods can I use?

Credit card, debit card, Instapay and mobile wallets. Cash on delivery is not offered.

What if it arrives damaged or expired?

Tell us within 1 day of delivery. Returns cover defective, damaged or expired items only; after verification the refund returns to your original payment method within 15–30 days.