Antioxidants/Redox and the Skin – What You Need To Know

Introduction

An antioxidant is a substance that prevents or slows oxidative damage in cells by neutralising free radicals or other reactive oxygen species, thereby protecting biological molecules such as DNA, proteins, and lipids from oxidation. In aesthetic medicine, it is important to understand which antioxidants are specifically beneficial for skin health.

Antioxidants relevant to the skin can be broadly divided into:

1. Endogenous antioxidants: produced naturally by the human body.

2. Exogenous antioxidants: obtained from external sources.

The exogenous group is considerably larger. These two groups will now be explored in more detail. In this article I will include some quick reference tables for practitioners to extract to keep in their clinics, if they wish, as this is such a large topic.

Endogenous

Endogenous antioxidants form the skin’s first line of defence against oxidative stress and are essential for maintaining cellular integrity, barrier function, and normal repair processes. These antioxidant systems operate continuously within the skin and work synergistically to neutralise reactive oxygen species generated by intrinsic metabolism and environmental exposure.

The skin possesses multiple endogenous antioxidant systems, including enzymatic and non-enzymatic pathways, which play a critical role in protecting keratinocytes, fibroblasts, melanocytes, and extracellular matrix components from oxidative damage.

Sub-Classification

1. Enzymatic Endogenous Antioxidants…

These have a high relevance for ageing, inflammation, and post procedure recovery

• Superoxide dismutase (SOD)

• Catalase

• Glutathione peroxidase

CLINICAL RELEVANCE: These decline with age, are reduced by UV exposure and pollution and as they are important for post inflammatory and wound healing processes , it’s important to note that older patients receiving skin treatments may have delayed healing and post recovery because of their decline.

2. Non-Enzymatic Endogenous Antioxidants..

these act as direct free radical scavengers and also support enzymatic systems

• Glutathione

• Uric acid

• Coenzyme Q10 (ubiquinone)

• Lipoic acid

• Melanin (often overlooked but very relevant in skin)

While endogenous antioxidant systems provide continuous intrinsic protection, they are insufficient to counteract the cumulative oxidative burden imposed by ultraviolet radiation, pollution, lifestyle factors, and aesthetic procedures. Exogenous antioxidants therefore play a crucial complementary role in maintaining skin redox balance.( REDOX discussed later)

Now let’s take a look at the exogenous group of anti-oxidants which are more relative to our clinical work.

Exogenous Antoixidants

Exogenous antioxidants are derived from dietary intake, supplementation, and topical application. This group is considerably larger and more diverse than endogenous antioxidants and includes many compounds with established relevance in aesthetic medicine.

Exogenous Sub-Categories

1. Vitamins

   • Vitamin C (ascorbic acid)

   • Vitamin E (tocopherols)

   • Vitamin A derivatives (retinoids, carotenoids)

2. Polyphenols

   • Flavonoids

   • Resveratrol

   • Green tea catechins

3. Carotenoids

   • β-carotene

   • Lycopene

   • Lutein

4. Trace Elements (Cofactors)

   • Zinc

   • Selenium

   • Copper

Clinical Relevance Of Redox

Redox, Oxidative Stress & Skin Ageing

What is REDOX?

• Reduction = gain of electrons

• Oxidation = loss of electrons

Why REDOX matters to skin..

1. Cell energy production.. mitochondria rely on redox reactions

2. Antioxidants work by donating electrons to neutralise free radicals

3. Inflammation and ageing are strongly influenced by redox balance

4. Wound healing and skin repair depend on controlled redox signalling

What is OXIDATIVE STRESS?

Oxidative stress occurs when there is an imbalance between oxidants and antioxidants in favour of oxidants.

• Oxidants = reactive oxygen species (ROS) / free radicals

• Antioxidants = molecules that neutralise ROS by donating electrons

This is fundamentally a REDOX imbalance 👍

2. Free Radicals & Redox Damage

Free radicals are electron-deficient molecules that:

• Steal electrons from healthy cells

• Trigger chain reactions of oxidation

• Damage:

  • Cell membranes (lipid peroxidation)

  • Proteins (enzyme dysfunction)

  • DNA (accelerated ageing, impaired repair)

In SKIN, this translates to:

• Fine lines & wrinkles

• Loss of elasticity

• Pigmentation irregularities

• Impaired barrier function

• Chronic inflammation

Common Sources Of Oxidative Stress In Skin

• UV radiation ( ❗ primary extrinsic ageing factor ❗ )

• Pollution & cigarette smoke

• Inflammation (acne, rosacea, dermatitis)

• Poor sleep & psychological stress

• Aggressive aesthetic treatments without adequate antioxidant support

Antioxidants = the REDOX stabilisers

Antioxidants donate electrons without becoming unstable themselves, effectively terminating free-radical chain reactions and reducing OXIDATIVE STRESS.

Important skin antioxidants:

• Vitamin C (ascorbic acid) – collagen synthesis, brightening, UV protection

• Vitamin E (tocopherol) – lipid membrane protection

• Glutathione – intracellular master antioxidant

• Niacinamide – supports redox balance and barrier repair

• Polyphenols (green tea, resveratol)

NB. Antioxidants often work synergistically (eg Vitamin C regenerates Vitamin E)

REDOX signalling vs REDOX damage

Not all oxidation is bad! Controlled redox reactions are essential for:

• Cell signalling

• Wound healing

• Immune defence

• Collagen remodelling post-procedure

⚠ Problems arise when oxidation is excessive or chronic, overwhelming antioxidant capacity.

❗ This is why:

• Over-treating skin

• Excessive peels/lasers without recovery

• Poor post-procedure antioxidant care

  …can actually accelerate ageing, not reverse it ❗

Important Clinical Relevance In Aesthetics

Understanding REDOX helps explain:

• Why antioxidant priming improves procedure outcomes

• Why post-treatment skincare is critical

• Why chronic inflammation leads to premature ageing

• Why combined internal +topical antioxidant strategy is more effective than either modality in isolation.

Modern aesthetic medicine aims to restore redox balance, not eliminate oxidation entirely ❗ REDOX balance strongly influences whether skin repairs, regenerates, or prematurely ages. ❗

Antioxidants Tables For Reference

Table 1. Enzymatic Endogenous Antioxidants

Table 2. Non-Enzymatic Endogenous Antioxidants

Exogenous Antioxidants Vitamin C

Table 3. Vitamins

Table 5. Carotenoids

Exogenous antioxidants – delivery route that actually works

• Vitamin C

  🟢 T – strong evidence (photoprotection, collagen, antioxidant)

  🔴 O – supports systemic antioxidant network & glutathione recycling

  ➡ T + O

• Vitamin E (α-tocopherol)

  🟢 T – synergistic with Vit C, lipid membrane protection

  🔴 O – systemic antioxidant, supports skin barrier

  ➡ T + O

• Vitamin A (retinoids / carotenoids)

  🟢 T – gold standard for skin ageing (retinoic acid, retinal)

  🔴 O – via carotenoids (not retinoic acid directly)

  ➡ T + O (different biological roles)

• Flavonoids (polyphenols)

  🟢 T – limited but supportive (surface antioxidant/anti-inflammatory)

  🔴 O – primary effective route

  ➡ O (primary) + T (adjunct)

• Resveratrol

  🟢 T – antioxidant, anti-inflammatory (stability dependent)

  🔴 O – poor bioavailability but systemic signalling effects

  ➡ T + O (modest evidence)

• Green tea catechins (EGCG)

  🟢 T – good evidence (UV protection, anti-inflammatory)

  🔴 O – strong systemic antioxidant & anti-inflammatory effects

  ➡ T + O

• β-Carotene

  🟢 T – minimal benefit

  🔴 O – primary effective route (photoprotection over time)

  ➡ O only

• Lycopene

  🟢 T – negligible penetration

  🔴 O – strong evidence for systemic & skin photoprotection

  ➡ O only

• Lutein

  🟢 T – emerging but limited evidence

  🔴 O – primary route (skin & eye antioxidant)

  ➡ O (primary) ± T (adjunct)

• Zinc

  🟢 T – anti-inflammatory, barrier support

  🔴 O – enzyme function, immune & antioxidant roles

  ➡ T + O

• Selenium

  🟢 T – no meaningful evidence

  🔴 O – essential for glutathione peroxidase

  ➡ O only

• Copper

  🟢 T – minimal relevance

  🔴 O – essential trace element (SOD, collagen cross-linking)

  ➡ O Only

Conclusion

“Topical antioxidants primarily protect against environmental oxidative stress, whereas oral antioxidants support intracellular endogenous antioxidant systems.”

Clinical Application in Aesthetic Practice

• Antioxidants support healing after procedures (lasers, microneedling, chemical peels).

• They reduce photodamage and minimise inflammation, improving treatment outcomes.

• Combination therapy (endogenous support + exogenous supplementation/topicals) is often most effective.

• Choosing evidence-based antioxidants can enhance long-term skin health and appearance.

Skin Antioxidant Network

Let’s Take A Look At The Master Antioxidant Glutathione

What Is Glutathione (Very Briefly)

• Glutathione (GSH) is the body’s master intracellular antioxidant

• Naturally produced in the liver

• Crucial for:

  • Redox balance

  • Detoxification

  • Melanin regulation (via tyrosinase inhibition & eumelanin shift)

Skin cells do use glutathione, but delivery is the challenge. As Glutathione is a large topic on its own I have set out a table below for aestheticians to refer to below showing modes of delivery and their relevance …

Summary Table – Glutathione Delivery As Regards Benefits To The Skin

(This will be of particular interest to those practitioners delivering Glutathione by IV/IM)

✅ Professional Conclusion

Glutathione is:

• Biologically important

• Clinically useful systemically (not topically)

• Over-marketed for skin

✴ For skin improvement, it works best when:

✔ Endogenous production is supported & boosted with NAC, Glycine, Vitamin C, Selenium (oral delivery)

✔ Used alongside vitamins C, A and E plus Ferulic acid (topicals) + SPF

✔ Not sold as a miracle whitening agent

The topicals do not increase intracellular glutathione, but they do protect the skin from depletion and support the same anti-oxidant network. So together, these reduce oxidative load, allowing endogenous glutathione to be preserved rather than consumed.

References

“The efficacy of topical antioxidants such as vitamin C, vitamin E, ferulic acid, niacinamide and copper peptides is supported by extensive in-vitro, in-vivo and clinical research.”

1. Masaki H. Role of antioxidants in the skin: anti-aging effects. Journal of Dermatological Science. 2010;58(2):85–90

2. Thiele JJ, Hsieh SN, Ekanayake-Mudiyanselage S. Vitamin E in human skin: organ-specific physiology and considerations for its use in dermatology. Molecular Aspects of Medicine. 2005;26(5–6):397–412.

3. Rinnerthaler M, et al. Oxidative stress in aging human skin. Biomolecules. 2015;5(2):545_589