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Duo Heroes

The Moisture Duo

4.9 | 165 verified reviews — Read what customers say

Theorem Serum Boost + The Grownup Moisturizer

  • Deep multi-layer hydration
  • Clinically proven collagen rebuilding for firmer skin
  • CeraLipids® and Super E to seal moisture in and support your barrier
  • Proprietary fermentation process for skin longevity

$144.00

Free shipping over $45 | Easy returns | Loved by 40,000+ customers

Description

Hydration your skin cannot hold is hydration you paid for and lost. Theorem Serum Boost draws moisture deep into the skin. The Grownup Moisturizer® is what keeps it there. Together they are the reason your skin still feels comfortable at the end of the day.

Mature skin has two problems at once. It makes less of the hyaluronic acid that keeps it plump, and it loses the lipids that hold moisture in. Treating only the first is why a good serum can still leave skin feeling tight by evening.

Theorem handles the delivery. The Grownup Moisturizer® handles the retention. CeraLipids® and Super E reinforce the barrier so hydration is not quietly evaporating all day, which matters more as humidity drops and the seasons turn.

That is how Skincare for Grownups® is meant to work. Not one product doing everything, but two steps doing more together than either does alone.

What's included in the Duo:

Theorem Serum Boost, 30 ml / 1.0 fl. oz.
Hyaluronic Molecular Nutrition and Bio-Intensified Peptide. Small-molecule hyaluronic reaches deeper to replenish the hydration mature skin makes less of on its own, while peptides support firmness underneath.

The Grownup Moisturizer®, 50 ml / 1.7 oz.
CeraLipids®, Super E and HA Peptide Nutrition. The seal. It reinforces the barrier that holds moisture in, so what the serum delivers actually stays put.

Ingredients

FULL INGREDIENT LIST:
Theorem Serum Boost
Water, Glycerin, Propanediol, Sodium Hyaluronate, Betaine, Disodium Edetate, Hydrolyzed Sodium Hyaluronate, Jasminum Sambac (Jasmine) Flower Extract, Crataegus Monogyna Flower Extract, Yeast Extract, Tetradecyl Aminobutyroylvalyaminobutyric Urea Trifluoroacetate, Caprylhydroxamic Acid, Sodium Benzoate, Soy Amino Acids, Melia Azadirachta Leaf Extract, Melia Azadirachta Flower Extract, Amino-Esters-1, Coccinia Indica Fruit Extract, Corallina Officinalis Extract

The Grownup Moisturizer
Water, Butyrospermum Parkii (Shea) Butter, Propanediol, Simmondsia Chinensis (Jojoba) Seed Oil, Polyglyceryl-10 Oleate, Brassica Alcohol, Polyglyceryl-6 Distearate, Heptyl Undecylenate, Methylheptylglycerin, Polyglyceryl-10 Dipalmitate, Glycerin, C13-16 Isoalkane, Glyceryl Oleate, Sodium Hyaluronate, Oryza Sativa (Rice) Bran Oil Extract, Coconut Alkanes, Porphyridium Cruentum Extract, Yeast Extract, Soy Amino Acid, Xanthan Gum, Caprylhydroxamic Acid, Tetradecyl Aminobutyroylvalylaminobutyric Urea Trifluoroacetate, Diheptyl Succinate, Capryloyl Glycerin/Sebacic Acid Copolymer, 1,2-Hexanediol, Caprylyl Glycol

How to Use

Theorem Serum Boost:
Use 1 to 2 dropperfuls on cleansed face & neck 2 times daily. Safe for use around the eye area, pat gently onto lid & undereye. May also be used on the hands and chest.

The Grownup Moisturizer

Apply a small amount on cleansed face, neck & decollete 2 times daily. May also be used on the hands and any other area where there is dryness. Use after serum.

Dermatologist Tested | Patented Tech | Women-Founded | Created in NYC




Key Benefits

Plumps. Firms. Rebuilds.

Our spectrum of HA's quickly work to help make skin (and eyes) behave and look younger through healthier skin that builds itself back up.

Clinical Results

100% of women noticed softer, firmer skin in just four weeks.*
97% said their skin looked 5 years younger — without a single filter.*
100% noticed deeper, lasting hydration, not just surface-level moisture.
100%

*Results seen after 4 weeks, 2x daily in users aged 40–69.

closeup of Theorem Serum Boost
Best Moisturizer for Mature Skin

THE GROWNUP MOISTURIZER®

Patent-pending Youth Enhancing CeraLipids® Lipid Replenishing Formula that Works to get Beneath Skin

GET DEEP MATURE SKIN CARE CREATED IN THE CAIRE LAB

YOUR SKIN WILL DRINK UP THIS RICH POTENT FORMULA

SUPER MOISTURE BOOST |Tiniest Potent Hyaluronic Acid

FIRMER UPPER |Supercharged GF1 Peptide & Natural Ceramide Mimicking Rice

GO DEEP |Proprietary Fermentation Process

LET'S GO LOOK YOUNGER!

Frequently Asked Questions

Who is the Moisture Duo for?

Skin 40 and over that feels tight, looks dull by evening, or seems to drink up whatever you put on it. If you are already using a serum and still reaching for more moisturizer by the afternoon, the issue is usually retention rather than the serum itself.

Will the moisturizer feel heavy or greasy?

No. It is formulated to absorb rather than sit on the surface, so it layers cleanly over the serum and works under makeup and SPF.

How soon will I notice a difference?

Comfort usually changes first, often within days, because you stop losing moisture as quickly through the day. Hydration and firmness build with consistent use over weeks rather than days. Skincare for Grownups® works by compounding, so results come from using it regularly, not occasionally.

Do I still need a cleanser?

Yes. This duo covers treat and seal, the second and third steps. What you cleanse with matters more than most people think, because a stripping cleanser undoes the barrier work this duo is doing. The Grownup Cleanser™ is a barrier-first balm designed to pair with it.

Can I use this with retinol or my other actives?

Yes. Apply Theorem Serum Boost to clean skin, then the moisturizer. If you use a retinol or a prescription treatment, keep applying it as your provider directs and layer around it as usual.

4.9339 Reviews

I'm 51 and I have had good skin my whole life until perimenopause, when I began getting stubborn acne. Within 2–3 days of using the serum, I noticed my acne beginning to clear up.

— Susan M.

My hygienist had to double-check my date of birth. She couldn't believe I was 60.

— Becky K.

Better than Shiseido and Lancôme serums. I've been using facial serums for 14 years, and Caire's was immediately absorbed by my skin.

— Mayumi Y.


Triple Lift Molecule Mask, Grownup Moisturizer, Theorem Serum Boost Quad Set

Skincare for Grownups®
Full-Size Quad Set

Four products. One complete routine. Built for the skin you have now. Cleanser, Serum, Moisturizer, and Mask — formulated to work together so results compound. Firmer, smoother, more hydrated skin. Faster.

Buy the full set and save $25.

Get the Quad Set