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What is glutathione?
Glutathione helps maintain normal immune system function and has antioxidant and detoxification effects. The sulfhydryl group on cysteine is its active group (hence often abbreviated as G-SH), which readily binds to certain drugs and toxins, giving it its detoxification properties. Glutathione is not only used in pharmaceuticals but also as a base ingredient in functional foods, widely applied in anti-aging, immune-boosting, and anti-tumor applications.
The detoxification effect of glutathione is mainly manifested in its ability to bind with various toxins, such as free radicals, heavy metals, and fluorides, to eliminate their toxicity, thereby converting harmful substances in the body into harmless substances and excreting them together.
The whitening mechanism of glutathione
Glutathione can reduce tyrosinase activity in three different ways: 1. Tyrosinase is directly inhibited by chelating copper sites with thiol groups. 2. Glutathione interferes with the cellular transfer of tyrosinase to premelanosomes, a prerequisite for melanin synthesis. 3. Inhibition of tyrosinase is achieved indirectly through its antioxidant effects.
Glutathione shifts melanin production from eumelanin to pheomelanin synthesis via a reaction between thiol and dopaquinone, leading to the formation of thiol-dopa conjugates. Glutathione possesses potent antioxidant capabilities and has been shown to scavenge reactive oxygen species induced by ultraviolet radiation in epidermal cells.
Glutathione supplement form
1. Oral capsules/tablets: the most common, but liposomal glutathione or S-acetylglutathione should be selected to improve absorption.
2. Intravenous injection: Performed by a doctor in a hospital, it can directly enter the bloodstream and has the strongest effect. It is often used to treat certain specific diseases.
3. Inhalation: Used for respiratory diseases.
4. External skincare: Add to serums and creams for whitening and anti-oxidation.
The effects of glutathione on the skin
Glutathione: A "scavenger" of free radicals in the human body
When skin is exposed to ultraviolet radiation, it produces a large number of free radicals, which activate melanocytes to produce melanin. Free radicals are also one of the main causes of accelerated aging.
However, glutathione is known as a "free radical harvester" and "scavenger," and can help eliminate free radicals in the body.
Skin care benefits of glutathione
1. Whitening and fading dark spots: Glutathione has a strong antioxidant capacity, which can reduce melanin in cells into light pigmentation, inhibit the formation of dark spots, prevent skin aging and pigmentation, and reduce melanin formation.
2. Antioxidant: In the glutathione molecule, cysteine can protect intracellular proteins from oxidation, bind to free radicals, accelerate the scavenging of free radicals, reduce oxidative damage to the body, and inhibit melanin production. Simultaneously, glutathione inhibits melanin production through multiple pathways and breaks down existing pigmentation, thereby preventing the formation of age spots. Therefore, it has antioxidant and age spot-fading effects, ultimately brightening the skin tone.
3. Anti-glycation: Glutathione has the ability to inhibit the non-enzymatic reaction between glucose and protein, which can reduce the damage of glucose to skin cells; at the same time, it can participate in the tricarboxylic acid cycle and sugar metabolism in the body, promote the metabolism of carbohydrates, fats and proteins, and also affect the metabolic process of cells, thus having an anti-glycation effect [2], and promoting the skin to slow down the aging process.
4. Regulates water-oil balance: Glutathione contains abundant natural moisturizing factors that can form a moisture protective film on the skin surface, maintain the integrity of the skin's stratum corneum moisture and fiber structure, accelerate blood circulation in the skin, enhance the skin's overall resistance and immunity, repair the skin's protective barrier, regulate water-oil balance, and maintain skin elasticity and firmness.
How to supplement glutathione?
Foods
Some foods contain glutathione or its precursors (such as cysteine, glutamic acid, etc.), which we can obtain through a balanced diet.
Vegetables such as spinach, broccoli, asparagus, and onions not only contain a certain amount of glutathione but are also rich in antioxidants such as vitamin C, which help protect glutathione from oxidation. Among them, broccoli has a relatively high glutathione content, and it is easily absorbed and utilized by the human body.
Fruits: Kiwi, strawberry, grape, orange, and other fruits are rich in vitamin C and glutathione precursors. Eating them in moderation can provide raw materials for the body to synthesize glutathione.
Meat: Beef, chicken, pork, and other meats contain a lot of cysteine, which is an important raw material for the synthesis of glutathione.
Supplements
In certain special circumstances, such as decreased glutathione synthesis capacity, chronic disease state, or increased oxidative stress leading to severe glutathione deficiency, glutathione supplementation may be considered.
Currently, glutathione supplements on the market are mainly available in two types: oral formulations and injectable formulations. Oral formulations are convenient to use, but their bioavailability is relatively low because glutathione may be broken down by digestive enzymes in the gastrointestinal tract. Injectable formulations can directly enter the bloodstream and have a faster onset of action, but they should be administered under the guidance of a doctor.
Among these methods, the combined infusion of glutathione and vitamin C injections is a clinical supplement based on their synergistic effect, particularly suitable for cases with strong oxidative stress. When used together, both can directly enter the bloodstream, rapidly increasing the concentration of active antioxidants in the body. On one hand, through the synergistic mechanism of "vitamin C scavenging free radicals - glutathione regenerating vitamin C," it effectively combats oxidative damage. On the other hand, the detoxification function of glutathione and the effects of vitamin C in promoting collagen synthesis and enhancing immune cell activity complement each other, further supporting the repair of physiological functions.
Limitations of glutathione
Despite its powerful effects, glutathione has a crucial prerequisite for its application—stability. Reduced glutathione (GSH), while highly effective, is extremely sensitive to light, water, and high temperatures, exhibiting poor stability. In aqueous solution, it can only be stored for 2 hours at room temperature, and even at low temperatures of 0–5°C, it can only be stored for 8 hours. In medical applications, reduced glutathione is typically stored as a lyophilized powder, requiring refrigeration or freezing during transportation and storage, and is dissolved before use to ensure its activity and effectiveness. However, in some cosmetic injections, if the core ingredient of a whitening injection is reduced glutathione, and it is not dissolved in powder before use but rather prepared as a pre-mixed solution, then the glutathione may have already been oxidized, losing most of its efficacy.
Similarly, reduced glutathione added to cosmetics is unlikely to maintain its activity long-term once added to toners, serums, lotions, or creams, and it quickly oxidizes and decomposes. Therefore, consumers may not experience the intended effects when using it. As for reduced glutathione in whitening pills and health supplements, although most are stored in powder form with a relatively long shelf life, its long-term stability at room temperature remains questionable. Studies have shown that the bioavailability of orally administered glutathione is low, and its actual effects on the human body are also controversial.
FAQ
What foods are high in glutathione?
While the human body can synthesize glutathione, some foods can also help increase glutathione levels in the body or promote its synthesis. Here are some foods high in glutathione or that contribute to glutathione production: cruciferous vegetables, garlic, onions, spinach, nuts and seeds, asparagus, etc.
What are the signs of glutathione deficiency?
Three disastrous consequences of glutathione deficiency in the liver: detoxification system collapse, the liver becomes a "toxin warehouse", oxidative stress goes out of control, liver cells suffer "internal explosion", and the liver disease process is accelerated: a "catalyst" from hepatitis to liver cancer.
Which is better, glutathione or vitamin C?
Glutathione and vitamin C each have their benefits. The choice should be made based on specific needs and circumstances. Glutathione's core function is to participate in liver detoxification and regulate immune function. Vitamin C can promote collagen synthesis and enhance antioxidant efficiency.
Conclusion
Glutathione can inhibit melanin production through multiple pathways, primarily through its powerful antioxidant properties. Glutathione can be used for skin whitening via oral, topical, and intravenous injection. However, due to safety concerns, I do not recommend long-term, high-dose use of glutathione for skin whitening.
Glutathione can be used to treat melasma, including oral, topical, and mesotherapy methods. Clinical studies have reported the maximum recommended dosage of glutathione for skin whitening and melasma removal as 500 mg/day for 8 weeks or 250 mg/day for 12 weeks. However, as a nutritional supplement, glutathione can be safely taken orally at a dose of 500 mg daily for more than a year.
