Dryness & Irritation

Sensitive & Redness

Y Theorem Repair Serum NAC Y²

The original serum to enhance total skin health.

Reparative collection Bestsellers
Sale price €260.00 Regular price
Regular price €260.00


The inspiration for 111SKIN, Dr Yannis originally developed a super serum to aid post-surgical scar healing. Word spread quickly about this powerful formula and its incredible ability to fade discolouration, visibly reduce wrinkles, repair stressed skin, protect against sun damage and environmental aggressors.

Only a small amount of this rich serum is needed to enjoy the effect. You can expect rejuvenated, nourished, plump skin and it will come to the rescue if your skin’s been exposed to extreme conditions such as the ski slope or safari sun.

An all round superhero, our Y Theorem Repair Serum NAC Y² will thoroughly and reliably rescue your skin and bring it back to life.


Word of mouth. When Dr Yannis began giving his special formula (known then as “Dramatic Healing Serum”) to his post-surgery patients, he was satisfied knowing that thanks to his groundbreaking NAC Y²™ formula, their scars would be dramatically improved. What he didn’t expect was for his patients to keep asking for more. The formula was so effective at creating a firmer, stronger, repaired complexion it became a key part of their facial skincare regimen. Dr Yannis realised quickly that he could help a lot more people to feel amazing in their own skin. He developed his healing balm into Y Theorem Repair Serum NAC Y² - and the rest is history.


Repairs, regenerates and protects. Science-backed healing. Tested in space - one of the most extreme ageing environments for the skin.


Aqua/Water/Eau, Glycerin, Sorbitol, Isopropyl Myristate, Aloe Barbadensis (Aloe Vera) Leaf Juice, Calendula Officinalis Extract, Alcohol, Aesculus Hippocastanum (Horse Chestnut/Marron) Seed Extract, Sodium Ascorbyl Phosphate, Acetyl Cysteine, Yeast Extract, Butylene Glycol, Disodium EDTA, Carbomer, Sodium Hydroxide, Sodium Benzoate, Potassium Sorbate, Ethylhexylglycerin, Phenoxyethanol, Citric Acid, Parfum/Fragrance.


The key ingredient NAC Y²™️, evolved out of Dr. Yannis’ collaboration with European biochemical engineers testing an ingredient called NAC on astronauts in Space, an extreme environment where skin ages more rapidly. The results were astounding.

This revolutionary ingredient complex is scientifically proven to promote glutathione production and encourage cellular renewal to visibly repair the skin and target the signs of premature ageing.

Dr. Yannis used this complex to develop his first ever formula, the Dramatic Healing Serum, the forerunner to our Y Theorem Repair Serum NAC Y²™.

The NAC Y²™️ complex is at the heart of all of the products in the Reparative collection.

  • NAC Y²™️

    Stimulates effectiveness of the most powerful intracellular antioxidant: Glutathione along with two additional ingredients: Escin which boosts circulation and oxygen capacity which are essential for healing and Vitamin C, an antioxidant vital for creating collagen

  • Vitamin C

    A potent antioxidant vital for synthesising collagen in the skin. It also works on pigmentation, fights free radicals and repairs and protects against UV damage.

  • Liquorice Root

    A potent botanical tyrosinase inhibitor that brightens, tones and reduces hyperpigmentation.


After cleansing, distribute 1-2 pumps between your fingertips and apply to your face and neck in an upward motion.
If used as part of a 111SKIN regimen, follow with 111SKIN Y Theorem Day Cream NAC Y² or Y Theorem Day Cream Light NAC Y².


What is NAC Y²™?

A trio of actives with superior antioxidant capabilities that harness the power of Glutathione, Vitamin C and Escin.

Is this suitable for all skin types and ages?

Yes. The formula provides the optimum conditions for enhanced collagen, elastin and hyaluronic acid production which benefits all skin types and ages.

Can I use this serum after clinical treatments such as micro-needling?

Originally created to treat trauma after surgery, this serum is the perfect partner for nourishing the skin, and accelerating repair following clinical treatments.

Will this balance redness in the skin?

The restorative effects of the Repair Serum can aid in reducing redness and soothing irritated skin, by providing it with reparative ingredients.