# 111SKIN Y Theorem Repair Light Serum NAC Y2 for combination skin

**Lovi Fit: Average fit for combination skin.**
Combination Skin Fit: High · Effectiveness: High · Safety: High.

Page: https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin

The Lovi Fit is the same in every country; only the stores and prices differ, and the ones here are for the Netherlands.

Brand: [111SKIN](https://lovi.care/skincare/nl/brands/111skin)
Category: [Serums and treatments](https://lovi.care/skincare/nl/best/serums)

This fit is calculated for the concerns frequently associated with combination skin: an oily T-zone, enlarged pores, and dry cheeks. For scores based on a full skin profile (12D face scan, goals, preferences), use the Lovi app.

Works for combination skin; other serums fit it better.

## Why this fit

- Offers moderate benefits for your combination skin, as niacinamide and acetyl cysteine work to enhance barrier resilience and reduce blemishes, though it does not specifically target oily shine.
- Glycerin and aloe barbadensis extract provide general hydration and soothing effects, which are supportive for your skin type.
- The product is safe for your combination skin, with no risks of irritation due to the absence of prohibited or harsh ingredients.

## Fit by skin type

- [Oily skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/oily-skin): Average
- [Dry skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/dry-skin): Average
- [Combination skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin): Average (this page)
- [Sensitive skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/sensitive-skin): Average
- [Acne-prone skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/acne-prone-skin): Average
- [Skin with dark spots](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/dark-spots): Average
- [Mature skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/mature-skin): Average
- [Dry sensitive skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/dry-sensitive-skin): Average
- [Oily acne-prone skin](https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/oily-acne-prone-skin): Average

## Key ingredients

Nac Y2, Niacinamide, Calendula Officinalis Extract, Aloe Barbadensis Extract, Acetyl Cysteine

## What the research says

- Topical N-acetylcysteine plus doxycycline achieved significantly greater improvements in total lesion count, inflammatory lesion count, IGA, GAGS, and CADI scores compared to benzoyl peroxide plus doxycycline in 40 patients with moderate acne vulgaris. ([Dermatology Practical & Conceptual, 2026](https://pubmed.ncbi.nlm.nih.gov/42190184/))
- Topical genistein and N-acetyl cysteine prevent ultraviolet-induced photoaging signaling pathways in human skin in vivo by inhibiting specific kinase activities and antioxidant mechanisms without acting as sunscreens. ([The Journal of Investigative Dermatology, 2003](https://pubmed.ncbi.nlm.nih.gov/12713590/))
- A single application of a moisturizing fluid containing hyaluronic acid 1%, glycerin 5%, and Centella asiatica stem cells extract significantly increased skin hydration by 29% and reduced transepidermal water loss at 24 hours compared to baseline and an untreated control site in twenty healthy women. ([Clinical, Cosmetic and Investigational Dermatology, 2017](https://pubmed.ncbi.nlm.nih.gov/28860834/))
- Glutathione amino acid precursors effectively increase cellular glutathione levels, reducing oxidative stress, ATP depletion, and DNA damage in human keratinocytes, clinical subjects, and ex vivo skin compared to controls. ([Journal of the European Academy of Dermatology and Venereology, 2024](https://pubmed.ncbi.nlm.nih.gov/38189670/))
- Topical glutathione improves hyperpigmentation, reduces ultraviolet-induced erythema and wrinkles, decreases transepidermal water loss, and enhances antioxidant capacity. ([The Journal of Clinical and Aesthetic Dermatology, 2025](https://pubmed.ncbi.nlm.nih.gov/41416233/))
- RayGel reduced skin reaction severity with a lower average score of 93.7 compared to 123.3 for the placebo group in patients undergoing whole breast external-beam irradiation. ([American Journal of Surgery, 2005](https://pubmed.ncbi.nlm.nih.gov/15862509/))
- Topical post-laser application of human adipocyte-derived mesenchymal stem cell media combined with niacinamide significantly improved wrinkle index, melanin index, patient satisfaction, and investigator esthetic improvement scores compared to vehicle cream in patients with aging skin. ([Journal of Cosmetic Dermatology, 2021](https://pubmed.ncbi.nlm.nih.gov/33103316/))
- Topical nicotinamide prevented solar-simulated UV-induced immunosuppression in healthy volunteers, and men experienced immunosuppression at solar-simulated UV doses three times lower than those required for women. ([The Journal of Investigative Dermatology, 2008](https://pubmed.ncbi.nlm.nih.gov/17882270/))
- Topical 5% niacinamide applied twice daily for 12 weeks reduced fine lines and wrinkles, hyperpigmented spots, red blotchiness, and skin sallowness, and improved skin elasticity compared to vehicle control in 50 female white subjects with facial photoaging. ([Dermatologic Surgery, 2005](https://pubmed.ncbi.nlm.nih.gov/16029679/))
- Topical application of Calendula officinalis extract cream significantly improved skin hydration and firmness (reflected in significant changes in R0 and R6 parameters) in 21 healthy human volunteers compared to a base cream. ([Acta Poloniae Pharmaceutica, 2011](https://pubmed.ncbi.nlm.nih.gov/21928714/))
- Treatment with standardized extract of Calendula officinalis L. led to a shorter epithelization time and faster healing speed compared to mineral oil in patients with acute skin loss wounds of the hand and fingers healing by secondary intention. ([Tissue Barriers, 2022](https://pubmed.ncbi.nlm.nih.gov/34674610/))
- Topical administration of Calendula provides weak evidence of effectiveness in acute and chronic wounds compared to standard treatments based on a narrative review of available trials. ([Wounds, 2008](https://pubmed.ncbi.nlm.nih.gov/25941793/))
- A cream combining propolis, tea tree oil, and Aloe vera reduced erythema scars, acne severity index, and total lesion count better than erythromycin cream in sixty patients with mild to moderate acne vulgaris compared to placebo. ([Clinical Pharmacology, 2018](https://pubmed.ncbi.nlm.nih.gov/30588129/))
- Topical aloe vera gel significantly accelerated split-thickness skin graft donor-site healing compared to placebo in 12 patients, but showed no significant difference in pain relief. ([Plastic and Reconstructive Surgery, 2018](https://pubmed.ncbi.nlm.nih.gov/29649056/))
- Topical application of Aloe vera cream reduced postoperative pain at rest and during defecation, accelerated wound healing at two weeks, and decreased analgesic requirements in patients after open hemorrhoidectomy compared to placebo. ([Journal of Alternative and Complementary Medicine, 2010](https://pubmed.ncbi.nlm.nih.gov/20569031/))
- Topical application of alpha-tocopherol, l-ascorbic acid, alpha-lipoic acid, glutathione ethylester, and N-acetylcysteine decreased UVB-radiation-induced cell death, apoptosis, and lipid peroxidation in ex vivo pig skin explants compared to untreated controls. ([Radiation Research, 2003](https://pubmed.ncbi.nlm.nih.gov/12537526/))
- Topical vitamin C, vitamin E, and acetylcysteine showed similar effects on the healing of experimentally created corneal wounds in rabbits, with no statistically significant differences compared to each other. ([Indian Journal of Ophthalmology, 2020](https://pubmed.ncbi.nlm.nih.gov/33229673/))
- Topical 3% N-acetylcysteine and dexpanthenol creams improved wound healing rates compared to no treatment in rats, showing comparable efficacy to each other. ([International Surgery, 2015](https://pubmed.ncbi.nlm.nih.gov/25583306/))

## Why other serums fit combination skin better

- Niacinamide and ferulic acid incorporated in a stable multiple emulsion successfully reduced melanin, sebum, and skin erythema while improving skin elasticity and hydration in human skin compared to a placebo. ([BioMed Research International, 2022](https://pubmed.ncbi.nlm.nih.gov/35342760/))

## What reviewers say

Users with oily, combination, or humid-climate skin praise the serum's lightweight, water-like texture for providing deep hydration without greasiness, often noting significant improvements in redness, inflammation, and post-procedure healing. A notable portion of reviewers feel the extremely high price point is unjustified, citing strong fragrance and a lack of dramatic anti-aging results as key drawbacks compared to more affordable alternatives.

- Liked: Lightweight & fast-absorbing (mostly mentioned)
- Disliked: Extremely expensive (mostly mentioned)
- Liked: Hydrating & plumping (often mentioned)
- Liked: Soothing & healing (often mentioned)
- Liked: Good for oily skin (sometimes noted)
- Disliked: Lack of visible results (sometimes noted)
- Disliked: Strong fragrance (sometimes noted)
- Disliked: Potential irritation (rarely noted)

## How to apply

- Use your serum as part of your PM routine. Start using it 3 times a week and move to daily use if your skin likes it.
- Apply the serum after cleansing and toner, and right before your moisturizer.
- Gently press 2-3 drops of the serum into your skin and wait a minute ⏳for it to soak in.
- Apply the serum on clean and dry skin since your skin is not sensitive.
- Always do a patch test before using the serum for the first time, and avoid the eye area .
- Video: https://storage.pora.ai/c879dda8655a61c19d3d8c9ebad6b06d.mp4

## Questions and answers

### How well does Y Theorem Repair Light Serum work for combination skin?

This serum offers moderate benefits for your combination skin, as niacinamide and acetyl cysteine help strengthen your skin barrier and reduce blemishes. However, to work best for this skin type, a treatment of this kind also needs ingredients that control oily shine and balance oiliness.
Sources: [Dermatology Practical & Conceptual, 2026](https://pubmed.ncbi.nlm.nih.gov/42190184/), [The Journal of Investigative Dermatology, 2003](https://pubmed.ncbi.nlm.nih.gov/12713590/)

### Which ingredients make this serum a good fit for combination skin?

Niacinamide and acetyl cysteine make this serum a good fit by helping strengthen your skin and calm blemishes. Glycerin and aloe vera also provide gentle hydration that supports your skin type. A product of this type needs ingredients like niacinamide and zinc PCA to manage oily shine and balance combination skin.
Sources: [Clinical, Cosmetic and Investigational Dermatology, 2017](https://pubmed.ncbi.nlm.nih.gov/28860834/), [Dermatology Practical & Conceptual, 2026](https://pubmed.ncbi.nlm.nih.gov/42190184/)

### What does Nac Y2 do for combination skin?

Nac Y2 acts as an antioxidant and anti-inflammatory agent, helping to protect and calm combination skin. It is supported by various studies and reviews for its topical applications in dermatology.
Sources: [Indian Journal of Dermatology, Venereology and Leprology, 2018](https://pubmed.ncbi.nlm.nih.gov/30246706/), [The Journal of Dermatology, 2025](https://pubmed.ncbi.nlm.nih.gov/38923010/)

### What does Niacinamide do for combination skin?

Niacinamide helps balance oily areas by reducing excess shine and pore size while keeping dry patches hydrated and smooth. It also works to calm redness and even out skin tone, making it very suitable for combination skin.
Sources: [The British Journal of Dermatology, 2002](https://pubmed.ncbi.nlm.nih.gov/12100180/), [Antioxidants, 2021](https://pubmed.ncbi.nlm.nih.gov/34439563/)

### Where does this serum go in a skincare routine for combination skin?

This treatment goes in the evening routine after cleansing and toning, and before moisturizing. Combination skin works best with products that control oily shine while providing hydration and soothing care.

### Can I use it with retinol, and in what order?

You can use this treatment alongside retinol by applying the retinol first, letting it absorb, and then following with this serum. This product is safe for your combination skin, with no risks of irritation due to the absence of harsh ingredients.

### How often should I use this serum?

You can use this treatment in your evening routine, as planned in your routine steps. To better suit your combination skin, this type of product also needs ingredients that help control oily shine.

### Can it clog pores, cause breakouts or purging for combination skin?

This serum is unlikely to cause irritation or breakouts on your combination skin, as it is free of harsh ingredients and contains niacinamide and acetyl cysteine to help reduce blemishes. However, because it does not target oily shine, combination skin often needs added oil-absorbing ingredients and lightweight, non-greasy hydrators to fully balance dry and oily areas.
Sources: [Dermatology Practical & Conceptual, 2026](https://pubmed.ncbi.nlm.nih.gov/42190184/)

### Is this serum fragrance-free and alcohol-free?

It contains fragrance (benzyl alcohol and parfum) and drying alcohol (alcohol).

## Alternatives for combination skin

- [Beauty of Joseon Propolis + Niacinamide Glow Serum](https://lovi.care/skincare/nl/p/beauty-of-joseon/propolis-niacinamide-glow-serum/for/combination-skin) — Superior fit — €10.20 at Amazon
- [Neogen Dermalogy Real Niacinamide 15% Firming Serum](https://lovi.care/skincare/nl/p/neogen-dermalogy/real-niacinamide-15-firming-serum/for/combination-skin) — Superior fit — €35.80 at Amazon
- [Augustinus Bader The Serum](https://lovi.care/skincare/nl/p/augustinus-bader/the-serum/for/combination-skin) — Superior fit — €474.90 at Amazon

## Pairs well with

- Cleanser: [Dr. Althea Amino Acid Gentle Bubble Cleanser](https://lovi.care/skincare/nl/p/dr-althea/amino-acid-gentle-bubble-cleanser/for/combination-skin) — Superior fit — €16.50 at Amazon
- Hydrating Toner: [Paula's Choice Pore-Reducing Toner](https://lovi.care/skincare/nl/p/paula-s-choice/skin-balancing-pore-reducing-toner/for/combination-skin) — Superior fit — €36.00 at Amazon
- Moisturizer: [SKIN1004 Centella Cream](https://lovi.care/skincare/nl/p/skin1004/centella-cream/for/combination-skin) — Superior fit — €19.20 at Amazon

## Where to buy

No store in Netherlands has a checked price for this product, so the page shows none.

## Ingredients

Water, Glycerin, Alcohol, Benzyl Alcohol, Aloe Barbadensis Extract, Calendula Officinalis Extract, Carbomer, Sodium Hydroxide, Aesculus Hippocastanum Extract, Sodium Ascorbyl Phosphate, Panthenol, Niacinamide, Thiamin, Riboflavin, Pyridoxine, Cyanocobalamin, Glycyrrhiza Glabra Root Extract Licorice Root Extract, Prunus Armeniaca Kernel Oil Apricot Kernel Oil, Acetyl Cysteine, Parfum
## About the Lovi Fit

Lovi: Unbiased, science-based skincare AI trained on real user outcomes.

Lovi calculates every fit score from the full ingredient list with brand-independent rules its dermatologists and cosmetic chemists build and review, and personalizes every pick with AI trained on the real results of millions of users. Lovi trains its fit score models on a proprietary dataset built from more than 10,000 expert-labeled products and more than 100,000 simulated examples, following an internally consistent methodology presented at Cosmoprof, AMWC, and Skin of Color Update. Levels from best to worst: Superior, High, Average, Low, Caution, Warning.

Behind this fit score: Nadia Kapleva, MS (Co-founder, Medical Director); Alexey Shagraev, PhD (Co-founder, CEO and CTO); Dr. Sofía Perea Pérez, MD, MSc (Medical Board); Aishani Shah, MD (Medical Board); Asya Zubkova, MS (Medical Board); Hanna Kurets, MD (Medical Board, Medical Advisor); Elina Nazarenko, MD (Medical Board); Victoria Derkova, MS (Medical Board).

Page built Nov 8, 2026.

More from Lovi: https://lovi.care/skincare/llms.txt

## This page in other countries

- United States: https://lovi.care/skincare/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- United Kingdom: https://lovi.care/skincare/uk/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Ireland: https://lovi.care/skincare/ie/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Germany: https://lovi.care/skincare/de/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- France: https://lovi.care/skincare/fr/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Italy: https://lovi.care/skincare/it/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Netherlands: https://lovi.care/skincare/nl/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin (this page)
- Spain: https://lovi.care/skincare/es/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Canada: https://lovi.care/skincare/ca/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Australia: https://lovi.care/skincare/au/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Singapore: https://lovi.care/skincare/sg/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- Saudi Arabia: https://lovi.care/skincare/sa/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin
- United Arab Emirates: https://lovi.care/skincare/ae/p/111skin/y-theorem-repair-light-serum-nac-y2/for/combination-skin