The Chemistry of L-Ascorbic Acid or Vitamin C?
Vitamin C is a widely recognized nutrient for skin health and general wellness. L-ascorbic acid, a form of Vitamin C, is commonly found in supplements and skincare products. It’s known for its mild exfoliating properties; L-ascorbic acid is a key ingredient in many skincare formulations. This article will explain the differences between L-ascorbic acid and natural Vitamin C, explore the manufacturing processes of L-ascorbic acid, and discuss how the body utilizes each for nutritional purposes. We’ll also dive into the antioxidant and pro-oxidant properties of Vitamin C and its stability in topical skincare applications. By the end of this article, you’ll understand why some companies avoid using L-ascorbic acid in skincare, despite its popularity.
Natural Vitamin C Components:
Vitamin C is a water-soluble nutrient in many foods and is known for its antioxidant properties. Natural Vitamin C consists of L-ascorbic acid, flavonoids, rutin (quercetin), vitamins J, K, and P Factor, and eight copper-based enzymes, such as tyrosinase, all of which are essential for various bodily functions.
L-Ascorbic Acid: A Simplified Vitamin C Component
L-ascorbic acid is the most commonly used Vitamin C form in supplements and skincare products. However, it represents just the outer shell of natural Vitamin C. While it shares some antioxidant benefits, L-ascorbic acid lacks the full spectrum of bioactive components found in natural Vitamin C, so it may not fully replicate the health benefits of Vitamin C derived from whole foods.
The Role of Complete Vitamin C in the Body
Complete Vitamin C is vital in collagen production for skin, tendons, ligaments, joints, and bones. It also supports wound healing, blood vessel health, and adrenal gland function. In addition, it protects cellular fluids from free radical damage, detoxifies heavy metals, and resupplies Vitamin E with electrons, helping maintain cellular integrity. The human body requires Vitamin C for over 300 metabolic processes. Since we cannot produce or store Vitamin C, a diet rich in Vitamin C is essential.
Skin Benefits of Vitamin C
Reduces the appearance of fine lines and wrinkles
Improves skin texture and tone
Protects against environmental damage
Boosts collagen production
Factors That Reduce Vitamin C in the Skin
Aging
Excessive UV light or pollutant exposure
Stress, smoking, and alcoholism
Viral infections or fever.
How Does the Body Use Vitamin C and L-ascorbic acid?
Vitamin C and L-ascorbic acid are antioxidants, but their metabolic pathways differ. Natural Vitamin C efficiently recycles in the body through the Redox Cycle, where oxidized Vitamin C (dehydroascorbic acid, DHA) converts back to its active form. DHA penetrates cells more efficiently and is reconverted into active ascorbic acid by glutathione and NADPH. This recycling process produces reactive oxygen species (ROS) to maintain the antioxidant properties of Vitamin C.
In contrast, synthetic L-ascorbic acid, commonly found in supplements, is not recycled as effectively. Excessive use of synthetic L-ascorbic acid can lead to oxidative stress, depleting essential nutrients like glutathione and disturbing mineral balances, particularly copper metabolism.
The Fenton Reaction occurs when free iron (Fe²⁺) reacts with hydrogen peroxide (H₂O₂) to produce hydroxyl radicals, which cause oxidative damage. Ceruloplasmin, a copper-binding enzyme, plays a crucial role in preventing this reaction by converting Fe²⁺ to Fe³⁺, thus reducing the availability of free iron that triggers the Fenton Reaction.
Excessive consumption of synthetic L-ascorbic acid can disrupt ceruloplasmin’s function, impairing copper and iron regulation and increasing the likelihood of oxidative stress, iron buildup, and potentially fatal Fenton reactions.
Both the Redox Cycling and Fenton Reaction contribute to oxidative stress, but they differ in mechanisms:
While the Fenton Reaction does not directly affect ceruloplasmin, improper iron regulation (which ceruloplasmin is responsible for) can lead to increased free Fe²⁺ levels, facilitating the Fenton Reaction. Conversely, oxidative stress generated by the Fenton Reaction can contribute to broader damage in the body, which might impair ceruloplasmin or other iron-regulating mechanisms. The connection lies in the balance of iron metabolism and oxidative stress, where both processes influence each other indirectly.
L-Ascorbic Acid Production:
China produces most of the world’s L-ascorbic acid, using corn as a raw material. The production process involves converting glucose into sorbitol, which is oxidized to sorbose by bacteria. After chemical acetone treatment, it converts into L-ascorbic acid.
Possible Causes of Oxidative Stress:
Imbalance in Recycling: If ascorbic acid oxidation to dehydroascorbic acid exceeds the body’s capacity to regenerate ascorbic acid, dehydroascorbic acid may accumulate and may breakdown into irreversible compounds like 2,3-diketogulonic acid and oxalic acid cause loss of antioxidant properties and degradation. Excess dehydroascorbic acid can cause oxidative stress if it is not efficiently recycled back to ascorbic acid.
Nutrient Depletion: If nutrients required for recycling, such as glutathione and NADPH, are depleted, it could prevent the regeneration of ascorbate and lead to oxidative stress.
Morely Robbins’ view, considers excessive synthetic vitamin C (l-ascorbic acid) consumption. His theory suggests that synthetic ascorbic acid supplementation in excess could create mineral imbalances that promote oxidative stress.
Excess Synthetic L-Ascorbic acid Supplementation
Considerations with Iron Absorption:
L-ascorbic acid supplementation can increase iron absorption from foods, which may be dangerous for individuals with hemochromatosis, where excess iron builds up in the body. Such individuals should avoid Vitamin C supplements. It decreases free iron in the blood, causing anemia.
The Kidney Foundation is concerned about elevated oxalate levels caused by vitamin C, which can increase the risk of developing kidney stones and harm the kidneys.
It increases the risk of periodontal disease, cataract development, atherosclerosis, and cardiovascular disease.
Pregnant women have underweight newborns.
If, after reading all this, you still want to use l-ascorbic acid!
Synthetic L-Ascorbic Acid in Skincare
Topical L-ascorbic acid is effective for brightening skin and reducing signs of aging, but it is also unstable. Its potency decreases when exposed to air, heat, or light. For optimal absorption, consumers: A 20% solution of soluble L-ascorbic acid with a pH of 2-3.5. Sensitive skin types should be tested with lower concentrations to avoid skin irritation or inflammation.
Key Skincare Tips for L-Ascorbic Acid Use
Avoid Using Certain Ingredients:
Do not combine with Retinol: Combining Retinol and Vitamin C can lead to skin irritation.
Do not combine with AHAs (Alpha-Hydroxy Acids), as these can destabilize Vitamin C and may cause irritation.
Timing: L-ascorbic acid is best applied at night to minimize degradation. If used during the day, it should always be paired with sunscreen to protect against environmental damage.
Stabilization: Combining L-ascorbic acid with antioxidants like Vitamin E and ferulic acid can improve its stability.
Storage: Store L-ascorbic acid products in a cool, dark place or refrigerator to extend their shelf life
Oxidized synthetic L-ascorbic acid (Vitamin C) does not recycle itself naturally. After two to four weeks, it turns orange or brown, indicating a loss of effectiveness and the potential to cause harm.
Pro-Oxidant Effects of L-ascorbic acid on the skin:
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Long-term use of vitamin C, especially when improperly formulated, might lead to skin inflammation or disruptions in the skin’s microbiome.
It can aggravate acne, contribute to skin irritation,
When oxidized, it breaks down collagen and elastin.
Interactions with Copper Peptides:
Some suggest waiting at least 15 minutes before using copper peptides after applying l-ascorbic acid to avoid compounding oxidative stress, while others suggest avoiding them completely.
Ingredients and products causing Fenton Reaction:
Cosmetics, skincare, toiletries, makeup, sunscreen, polluted air, and water can contain trace iron and copper. Phosphates contain trace amounts of iron and copper. Copper is 80 times more reactive than iron.
Common Foods High in Vitamin C:
Eating fresh foods like bell peppers, strawberries, blackcurrants, broccoli, Brussels sprouts, potatoes, cantaloupe, persimmons, and citrus fruits is the best way to acquire vitamin C.
Cooking reduces vitamin C levels. Its water-solubility raises the potential to lose vitamins that seep into unconsumed cooking liquid.
Food sources that are higher in Vitamin C than citrus fruits.
Acerola cherries, some rose hips varieties, greens like amaranth, goosefoot, pokeweed, wild leek, and watercress. Citrus fruit peels have more Vitamin C than the fruit itself. For nature lovers, forage wild currants, elderberries, gooseberries, and baked apple berries.
Recommended Vitamin C Intake:
Adult men and women need 100–120 mg/day of vitamin C. Consumers who eat appropriate amounts of fruit and vegetables daily get adequate vitamin C. The body excretes any excess of this water-soluble vitamin from its elimination system, so we do not need to take mega doses.
Suggested forms of Complete Vitamin C
people sensitive to corn should look for whole-food vitamin C alternatives
Below are affiliate links to vitamin C supplements derived from actual foods which are available on Amazon.
Conclusion:
Vitamin C is vital for over 300 bodily functions, including antioxidant defence and collagen production. However, it’s crucial to differentiate between natural Vitamin C and synthetic L-ascorbic acid. While L-ascorbic acid is in many supplements and skincare, it doesn’t offer the full benefits of complete Vitamin C, which includes a broader range of bioactive components. Excessive use of synthetic L-ascorbic acid can lead to oxidative stress and mineral imbalances.
The Environmental Working Group (EWG) rates products containing L-ascorbic acid between 1 and 9, highlighting concerns over their safety and efficacy. Research on the effectiveness of topical vitamin C formulations is limited due to their instability, weak skin permeability, potential interactions with metals and the inability to obtain optimal conditions. Therefore, it’s best to obtain vitamin C from whole food sources or supplements that use whole food vitamin C rather than relying on synthetic alternatives in skincare and supplements.
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