All you need to know about zinc gluconate.

Zinc is a crucial element for the proper functioning of the body and the maintenance of skin health. Naturally present in small amounts in the body, the intake of zinc is primarily ensured by diet and sometimes by taking dietary supplements. In addition to participating in the development of the body's tissues, this element is involved in the metabolism of certain proteins, lipids and carbohydrates.

However, zinc is not stable and cannot be used as such in cosmetic formulation. This is why it is incorporated in various forms, such as zinc PCA, zinc lactate, zinc oxide or zinc gluconate. The latter has the chemical formula C12H22O14Zn and is composed of two gluconate anions, each carrying a negative charge, and a zinc cation, carrying two positive charges. Zinc gluconate presents itself as a white and colourless powder.

The synthesis of zinc gluconate used for formulating cosmetics or medicines is carried out in a laboratory, adhering to strict hygiene and safety rules. This active ingredient is obtained from gluconic acid and zinc. Here are the main stages of this process:

1. Preparation of Gluconic Acid : Gluconic acid is typically produced following the enzymatic oxidation of glucose, a natural sugar molecule. This step involves one or more metallic catalysts.

2. Chelation reaction with zinc : once the gluconic acid is prepared, it is mixed with a solution of metallic zinc. The zinc then chelates the gluconic acid and binds to it through what are known as coordination bonds. This reaction results in the formation of zinc gluconate, in the form of a complex.

3. Purification and Crystallisation : In order to eliminate any residual traces of zinc or gluconic acid and to obtain only zinc gluconate, the complex is purified and subjected to a crystallisation process before being dried under vacuum.

Whether it is taken orally or incorporated into topical treatments for the skin or hair, the zinc gluconate has numerous virtues.

• Zinc gluconate combats hyperseborrhea.

  Zinc gluconate is a treatment highly favoured by those with oily skin for its sebum-regulating virtues. It inhibits the activity of the 5-α-reductaseenzyme, which catalyses the transformation of testosterone into dihydrotestosterone (DHT). When DHT binds to a cytosolic receptor in the sebaceous glands, it intensifies sebum production. By inhibiting this process, zinc gluconate reduces the shiny appearance of oily skin and limits the risk of imperfections related to the obstruction of skin pores by sebum.

• Zinc gluconate is an antioxidant active ingredient.

  Zinc gluconate combats oxidative stress, a source of free radicals. These are unstable molecules that damage cells, DNA, and proteins in the body. By stimulating the activity of the superoxide dismutase (SOD), an antioxidant enzyme, zinc gluconate prevents the appearance of wrinkles, fine lines, and age spots.

• Zinc gluconate has anti-inflammatory and soothing properties.

  Studies have also shown that zinc gluconate inhibits the release of tumour necrosis factor (TNF-α). This pro-inflammatory cytokine operates at several levels to intensify inflammation and contribute to redness and itching phenomena. Zinc gluconate helps to reduce irritation and soothe the skin and scalp.

• Zinc gluconate possesses antibacterial properties.

  Zinc gluconate also has antibacterial activity and helps regulate the populations of microorganisms living on our skin. This active ingredient particularly has a inhibitory effect on the growth of Cutibacterium acnes, the bacteria associated with acne. Therefore, zinc gluconate can be used to reduce and prevent blemishes.

• Zinc gluconate aids in wound healing.

  Zinc gluconate is also a valuable ally when it comes to aiding skin healing, following a minor injury or as a result ofinflammatory acne for instance. This active ingredient works by stimulating the production of keratinocytes and fibroblasts. Keratinocytes are the cells that make up more than 85% of the epidermis and fibroblasts are the primary cells of connective tissue, playing a protective role. Thus, zinc gluconate promotes the synthesis of scar tissue.

• Zinc gluconate reduces dandruff.

  Studies have also focused on the anti-dandruff properties of zinc gluconate. Dandruff is a multifactorial issue that can particularly result from a hyperseborrhea or a colonisation by fungi Malassezia. In addition to being seboregulatory, zinc gluconate has antifungal activity against these parasites. It is therefore often included in the composition of anti-dandruff shampoos.

• Zinc gluconate prevents hair loss.

  Finally, studies have highlighted that zinc gluconate is capable of preventing hair loss. This property is explained by its inhibitory action on 5-α-reductase, the enzyme responsible for the conversion of testosterone into dihydrotestosterone (DHT). DHT intensifies the activity of interleukin-6 (IL-6), cytokines that accelerate the transition between the growth and rest phases of hair. Thus, DHT more rapidly induces hair follicles into the telogen phase, or hair shedding phase. By inhibiting 5-α-reductase, zinc gluconate protects hair from hormonal fluctuations or genetic predispositions leading to an increased production of DHT and consequently to hair loss.

As of today, there are noknown adverse effects associated with the topical application of zinc gluconate. Generally incorporated at rates between 0.1 and 5% in cosmetic care, this active ingredient is considered safe and can even be used by pregnant and/or breastfeeding women. It has also been shown that zinc gluconate is not photosensitising.

Regarding its oral intake, it's worth noting that zinc gluconate seldom leads to adverse effects when consumed in proportions recommended by doctors. Furthermore, while zinc gluconate intake is feasible for pregnant and/or breastfeeding women, we still advise you to consult your doctor beforehand. Among the rare side effects reported following the oral intake of zinc gluconate, we can mention abdominal pain, nausea, and skin rashes. It is generally recommended not to exceed 30 mg of zinc per day, which equates to 208 mg of zinc gluconate.

A recent clinical case has demonstrated that the daily oral intake of 2000 mg of zinc gluconate over a six-month period could lead to a severe nephrosis, which is a degenerative and non-inflammatory lesion of the kidney tissue, and a anaemia corresponding to a copper deficiency induced by zinc. This case highlights the importance of adhering to prescribed dosages when it comes to oral medication or dietary supplement intake, as zinc gluconate is a potent active ingredient.

• HEIN M. Copper deficiency anemia and nephrosis in zinc-toxicity: a case report. South Dakota journal of medicine (2003).

• SIGLER M. & al. Effect of a novel dietary supplement on skin aging in post-menopausal women. European Journal of Clinical Nutrition (2006).

• KALINOWSKA-LIS U. & al. Zinc-containing compounds for personal care applications. International Journal of Cosmetic Science (2018).

• LE FLOCH C. & al. Assessment of the Benefit of a Deep Cleansing Gel Containing Salicylic Acid 2%, Zinc Gluconate 0.2% and Lipohydroxy Acids 0.05% in Patients with Mild to Moderate Truncal Acne: Results from an Exploratory Study. Clinical, cosmetic and investigational dermatology (2023).