Ascorbyl Glucoside: what is this active ingredient?

The essentials to remember about Ascorbyl Glucoside.

Ascorbyl Glucoside is a stable derivative of vitamin C, which is converted into active ascorbic acid within the skin.
Ascorbyl glucoside provides antioxidant protection to the skin.
Ascorbyl Glucoside exhibits skin-brightening effects and improves the evenness of skin tone.
Ascorbyl glucoside could also contribute to reducing wrinkles and fine lines.
The safety profile of Ascorbyl Glucoside is excellent: non-irritant, non-photosensitising, non-genotoxic and well tolerated.

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Ascorbyl Glucoside, in brief.

Ascorbyl Glucoside, also known as ascorbyl glucoside, is a water-soluble derivative of vitamin C, obtained by linking ascorbic acid to a glucose molecule. This structural modification primarily aims to enhance the stability of vitamin C, which is naturally susceptible to oxidation, light and air. In cosmetics, this increased stability allows for better preservation of formulations and more convenient everyday use.

Structure chimique de l'Ascorbyl Glucoside. — Chemical structure of Ascorbyl Glucoside.
Source: PubChem.

Once applied to the skin, Ascorbyl Glucoside is not active as such: it must be hydrolysed by skin enzymes, such as α-glucosidases, to gradually release free ascorbic acid. Thanks to this gradual release, ascorbyl glucoside is generally better tolerated than pure vitamin C, particularly on sensitive or reactive skin. In contrast, this enzymatic conversion involves a gentler and often slower action compared with vitamin C pure.

Chemical and physical characteristics	Values
Chemical formula	C12H18O11
Name	Ascorbyl Glucoside
Aspect	White powder
Molar mass	338.26 g/mol
Dosage	Generally used between 2 and 5%
Solubility	Soluble in water

Physico-chemical characteristics of Ascorbyl Glucoside.

What benefits does Ascorbyl Glucoside offer?

L-Ascorbyl Glucoside is primarily used for its role in protecting the skin against oxidative stress. It thus helps the skin to combat free radicals, unstable molecules that, by reacting with cellular components, can degrade them. Free radicals can in particular disrupt the network of collagen and elastin in the extracellular matrix and accelerate skin laxity and the appearance of wrinkles. Regular use of antioxidants, such as ascorbyl glucoside, helps to prevent this phenomenon.

A comparative study on human skin explants evaluated the cutaneous delivery, stability and antioxidant efficacy of a formulation containing 1.8% ascorbyl glucoside, compared with another containing 15% ascorbic acid. The results show that ascorbyl glucoside is completely converted into ascorbic acid by the skin before crossing the skin barrier, while leaving a non-metabolised fraction in the tissues, thus constituting a reservoir available for subsequent conversion. This kinetic profile suggests a sustained antioxidant action over time, rather than a transient peak in activity.

From a functional perspective, the antioxidant efficacy was evaluated using several oxidative stress markers, including malondialdehyde (MDA), superoxide dismutase (SOD) and catalase. Although the absolute amount of ascorbic acid in the skin was higher following direct application of ascorbic acid, both formulations exhibited equivalent antioxidant protection across all measured parameters. These findings suggest that a lower concentration of Ascorbyl Glucoside can offer efficacy comparable to that of ascorbic acid, whilst providing superior chemical stability.

Ascorbyl Glucoside is also under investigation for its potential depigmenting effect. It works by modulating the activity of tyrosinase, a key enzyme in melanin synthesis, which may help to gradually reduce hyperpigmentation and achieve a more even skin tone. A clinical study involving 27 Japanese women with solar lentigines assessed the effect of a 28% lotion containing an Ascorbyl Glucoside–arginine derivative complex (AGAC), applied twice daily for 24 weeks to one side of the face, compared with a placebo on the other side. The results showed a significant decrease in pigmentation scores in the treated area compared with placebo as early as 12 weeks, with even more pronounced effects at 24 weeks. However, the numerical values were not disclosed by the researchers.

This suggests that ascorbyl glucoside could be relevant for preventing and addressing the signs of photoageing.

Note : Studies in vitro have also shown that ascorbyl glucoside inhibits the activity of collagenase and elastase, two enzymes respectively responsible for the degradation of collagen and elastin. This mechanism of action, if confirmed in vivo, could also be useful in combating signs of skin ageing.

Reasons to be cautious about Ascorbyl Glucoside?

The safety of ascorbyl glucoside use was recently assessed by the CIR (Expert Panel for Cosmetic Ingredient Safety), an independent group of scientists specialising in toxicology and the evaluation of cosmetic ingredients. This panel reviews available data on cutaneous effects, systemic toxicity and chemical interactions to establish whether an ingredient can be considered safe in cosmetic products. After analysing the available studies, the CIR concluded that Ascorbyl Glucoside is safe for cosmetic use, does not pose a risk of photosensitisation, is not skin irritating and is neither genotoxic nor carcinogenic.

For example, its irritation and sensitisation potential was assessed via a test involving 51 volunteers. Occlusive patches containing a 10% Ascorbyl Glucoside solution were applied repeatedly over three weeks, followed by a treatment-free period and a challenge phase on a different area of skin. Reactions were evaluated on a 0 to 4 scale. None of the participants showed any adverse effects, and no contact sensitisation or allergy was observed after repeated product application. Other patch tests conducted in separate studies arrived at the same conclusions.