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111SKIN Y Theorem Repair Light Serum NAC Y2 for mature skin

Rated by Lovi · Unbiased, science-based skincare AI trained on real user outcomes

111SKIN Y Theorem Repair Light Serum NAC Y2

Average

  • HighNormal Skin Fit
  • AverageEffectiveness
  • ExcellentSafety

Works for mature skin; other serums fit it better.

This fit is calculated for the concerns frequently associated with mature skin: fine lines, wrinkles, and loss of firmness. For scores and recommendations based on your full skin profile, including your 12D face scan results and any goals or preferences you have, please use the Lovi app.

Page built Nov 8, 2026How the Fit score works

Lovi Assistant explains

  • Offers moderate benefits for your normal skin, as acetyl cysteine and niacinamide enhance barrier resilience and even skin tone, while glycerin and aloe barbadensis extract provide hydration.
  • While it offers general skincare benefits, it lacks specialized ingredients to effectively target your wrinkles and fine lines.
  • The product is safe for your normal skin due to the absence of harsh ingredients and the presence of soothing agents like Aloe Barbadensis Extract and Calendula Officinalis Extract.

How to apply

  • Use this serum in your PM routine. Start by applying it 3 times a week, and work up to daily use if your skin likes it.
  • Apply this serum after your toner and before your moisturizer.
  • Gently press 2-3 drops of the serum into your skin and let it absorb for a minute.
  • You can apply the serum on dry skin for the best results against fine lines.
  • Always do a patch test before your first use and avoid the sensitive eye area.

People Say

★4.2Overall rating based on 200+ reviews

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.

Highlights

  • Lightweight & fast-absorbing Mostly Mentioned
    • “absorbs almost instantly”
    • “water-like texture”
    • “not sticky or tacky”
    • “perfect for oilier skin”
  • Extremely expensive Mostly Mentioned
    • “not worth the money”
    • “terrible for money”
    • “understandable to balk at the price”
    • “overpriced for what it is”
  • Hydrating & plumping Often Mentioned
    • “skin was baby-soft”
    • “beaming with light”
    • “hydrates and plumps”
    • “woke up looking radiant”
  • Soothing & healing Often Mentioned
    • “calms my very sensitive skin”
    • “heals and evens out acne scars”
    • “reduced redness”
    • “great for post-procedure”
  • Good for oily skin Sometimes Noted
    • “didn't leave me feeling greasy”
    • “perfect for oilier skin types”
    • “balanced my oily skin”
  • Lack of visible results Sometimes Noted
    • “just ok”
    • “none of them did anything”
    • “didn't see a difference”
    • “all hype”
  • Strong fragrance Sometimes Noted
    • “smells absolutely revolting”
    • “wish it wasn't fragranced”
    • “strong floral scent”
    • “smell is too much”
  • Potential irritation Rarely Noted
    • “winced when applied”
    • “not for sensitive skin”
    • “caused a reaction”

Sources: lovi.care, sephora.co.uk, spacenk.com, cultbeauty.co.uk, dermstore.com, neimanmarcus.com, and more

Questions and answers

How well does 111SKIN Y Theorem Repair Light Serum work for mature skin?

This serum works moderately well for mature skin, helping to even skin tone and provide hydration, but it lacks specialized ingredients to effectively target wrinkles and fine lines. A product of this type needs high-quality anti-aging ingredients, potent antioxidants, peptides, and deep moisturizers to smooth lines and improve skin elasticity.

The British Journal of Dermatology, 2002

Which ingredients make this serum a good fit for mature skin?

Acetyl cysteine and niacinamide help make this serum a good fit for mature skin by supporting skin barrier resilience and evening out skin tone, while glycerin and aloe provide hydration. Because it lacks specialized ingredients to effectively target wrinkles and fine lines, a treatment for mature skin needs potent antioxidants, peptides, and high-quality ingredients that specifically improve skin firmness and hydration.

The British Journal of Dermatology, 2002

What does Nac Y2 do for mature skin?

NAC Y2 helps support mature skin by acting as an antioxidant that protects against environmental damage and helps smooth the look of lines. It is unlikely to cause irritation and works well to keep skin looking calm and healthy.

The Journal of Investigative Dermatology, 2003Indian Journal of Dermatology, Venereology and Leprology, 2018

What does Niacinamide do for mature skin?

Niacinamide helps mature skin by smoothing out fine lines and wrinkles, reducing dark spots, and improving overall skin elasticity. It is also very well tolerated and supports a strong skin barrier to keep skin looking healthy.

Antioxidants, 2021Journal of Cosmetic Dermatology, 2004

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

This serum goes in the evening routine after cleansing and before your moisturizer. Treatments with actives are placed in the evening for simplicity and extra safety around sun exposure.

Can I use this serum with retinol, and in what order?

You can use this treatment alongside retinol by applying the serum first and following it with your retinol product, or by alternating the nights you use each one. Because this product is safe for your skin and helps soothe irritation, layering them is unlikely to cause discomfort.

How often should I use this serum?

You can use this serum in your evening routine. A product of this type for mature skin needs powerful anti-aging ingredients like retinoids or peptides to effectively smooth fine lines and wrinkles.

Can this serum clog pores, cause breakouts or purging for mature skin?

This serum is unlikely to clog pores or cause breakouts for mature skin because it avoids heavy oils and includes soothing ingredients like aloe and calendula. A product of this type needs specialized anti-aging ingredients like peptides or retinoids along with rich hydrators to truly smooth and firm mature skin.

Is this serum fragrance-free and alcohol-free?

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

What the research says

  • Niacinamide significantly decreased hyperpigmentation and increased skin lightness compared with vehicle alone after 4 weeks of use in women by inhibiting melanosome transfer.

    The British Journal of Dermatology, 2002

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • Topical 2% niacinamide significantly decreased sebum excretion rate in Japanese individuals and casual sebum levels in Caucasian individuals compared to placebo or baseline.

    Journal of Cosmetic and Laser Therapy, 2006

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

  • 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

Why other serums fit mature skin better

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

Behind this fit score

Lovi calculates every fit score from the full ingredient list with brand-independent rules our 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.

  • Nadia Kapleva, MS

    Nadia Kapleva, MS

    Co-founder, Medical Director

    Cosmetic chemist, cosmetologist, aesthetic products developer

  • Alexey Shagraev, PhD

    Alexey Shagraev, PhD

    Co-founder, CEO and CTO

    PhD in computer science, 3x US patent holder, ex-Google, ex-Yandex

  • Dr. Sofía Perea Pérez, MD, MSc

    Dr. Sofía Perea Pérez, MD, MSc

    Medical Board

    Aesthetic medicine practitioner, MSc in Longevity and Anti-Aging Medicine

  • Aishani Shah, MD

    Aishani Shah, MD

    Medical Board

    Specialist dermatologist, MBBS, MD, IFAAD

  • Asya Zubkova, MS

    Asya Zubkova, MS

    Medical Board

    Cosmetic chemist, SCS, IFSCC member

  • Hanna Kurets, MD

    Hanna Kurets, MD

    Medical Board, Medical Advisor

    Dermatology MD

  • Elina Nazarenko, MD

    Elina Nazarenko, MD

    Medical Board

    Dermatology and diagnostic consultant

  • Victoria Derkova, MS

    Victoria Derkova, MS

    Medical Board

    Cosmetic chemist, cosmetic development technologist

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How does it fit your skin?

Scan your face, then any product: Lovi shows how well it fits you and what fits even better.

QR code: get the Lovi app
Download on theApp Store Get it onGoogle Play