Solutions of hydroquinone are stabilized against deterioration in color and odor with age by the addition to the solution of small amounts of citric acid.
In all formulations, hydroquinone is unstable turning brown upon contact with air. Once the hydroquinone has oxidized, it is no longer active and should be discarded.
Hydroquinone is applied topically just to the hyperpigmented skin only, twice daily for 3 months, after which time many patients maintain their improvement by using it twice each week. If there has been no benefit after 3 months of treatment, then the hydroquinone should be stopped.
Kojic acid has tendency to oxidize over time; add vitamin E tocopherol or BHT to a formula to reduce oxidation. For external use only. All kinds of skin-lightening products including lotions, creams, fluids, makeup products.
Antioxidants, preferably sulfites, including but not limited to sulfites, bisulfites, metabisulfites, their salts, and their derivatives, most preferably sodium metabisulfite, have been used to stabilize certain compositions, which have included hydroquinone.
We recommend taking a 2 month break after 3 months of application. Since hydroquinone is a photosensitive agent, It is also important to use SPF 30 or higher daily when on hydroquinone.
Antioxidants and free radicals
Antioxidants are found in certain foods and may prevent some of the damage caused by free radicals by neutralising them. These include the nutrient antioxidants, vitamins A, C and E, and the minerals copper, zinc and selenium.
One useful, if obvious, solution to the problem would be to add a preservative such as sodium metabisulphite. Sodium metabisulphite is in a class of preservatives that release sulphur dioxide. This increases the stability of kojic acid noticeably, keeping discolouration to a low level for up to two months.
Incorporating antioxidants into your skincare routine can help minimise the effects of oxidative stress. Look for products containing ingredients like vitamin E, vitamin C, and niacinamide, which neutralize free radicals and protect the skin from damage.
Hydroquinone has a pretty short shelf life. After a couple of months, it can start to break down and lose its potency, meaning it becomes less effective.
Storage: Store hydroquinone at room temperature (between 15-30° C or 59-86° F) away from moisture, heat, and direct light in its original container. You can refrigerate this medicine (between 36-46° F) but you should not freeze it.
A spokesman for the manufacturer says the discoloration is due to oxidation of hydroquinone and that the same color can be seen on the surface of the cream if it is exposed to air for a long time.
A hydroquinone is a compound with two hydroxyl (OH) groups bound to aromatic carbons, which can be reversibly oxidized by 2 electrons to a quinone (with two double bonded oxygens), which makes this family of compounds useful in electron transport chains.
Long-lasting changes can occur when kojic acid is part of a comprehensive skincare routine that includes other potent ingredients like vitamin C, retinoids, and sun protection. The combination of these ingredients can enhance the effects of kojic acid, leading to more sustained results.
On the other hand, certain ingredients can trigger irritation and should be avoided if you're using kojic acid in your skincare routine. Harsh acids, like alpha-hydroxy acids (AHAs), are a prime example, as well as certain retinoids.
If you have dry or damaged skin it might be more susceptible to the potential darkening effects of kojic acid. Ensuring your skin is healthy and well-nourished is key to making kojic acid work in your favor. A balanced diet, ample hydration, and a good sleep cycle can all contribute to healthier skin.
Oxidation cannot truly be prevented, but the process can be significantly slowed by the use of antioxidants. Antioxidants are compounds which interrupt the oxidation process by preferentially reacting with the fat radical to from a stable radical which does not quickly react with oxygen.
Results. Lemon juice, Vinegar, clear soda will all prevent food from turning brown quickly. These liquids are acidic, so they will lower the pH of the food surface. Olive oil, will also prevent food from browning, but is less effective than the acids.
To reverse oxidation, reduction reactions are often employed. Reduction is the chemical process in which a substance gains electrons, effectively counteracting oxidation. For instance, rust on iron can be treated with chemical reducing agents, such as acid cleaners.
2,3 To address these skin concerns, dermatologists recommend topical vitamin C and retinoids as their gold-standard treatment. Different forms of vitamin C are used in topical anti-aging skincare products.
Glytone Rejuvenating Mini Peel Gel
This dermatologist-recommended chemical exfoliator can help improve uneven skin tone, rough texture, fine lines, and breakouts. We love it if you're looking for a potent, all-rounder treatment. It's also ideal for mature skin since it works to address fine lines and hyperpigmentation.