Vitamin C is one of the most sought-after ingredients in skincare products in recent years by beauty lovers, with products claiming to have anti-oxidising, anti-ageing, whitening and blemish-lightening properties. There is also an expanding selection of products on the market that contain vitamin C. According to the Consumer Council’s test on 17 serums or beauty essence products labelled as containing vitamin C (also known as ascorbic acid), the vitamin C content ranged from not detected (1 model) to the highest of 13%. Among the 12 models labelled with vitamin C concentrations, 10 were found to be lower than the labelled value with a discrepancy of 0.2% to 6%, whereas 1 model was 1% higher than the labelled concentration. 5 models did not have any labelling information on the concentration of vitamin C, indicating a lack of information transparency. Based on overseas research reports, skincare products containing vitamin C concentrations between 10% and 20% would have an increase in their stability and ability to penetrate the skin. The measured concentrations of 5 models fell within this range, while that of another 4 models were close to 10%. Furthermore, 7 models were found to contain fragrance allergens (from 1 to 3 types) with restricted use according to the Cosmetic Regulation of the European Union (EU), and the detected amounts generally exceeded the upper limit (0.001%) that required labelling under the Regulation, yet only 3 models had all or part of the relevant ingredients clearly labelled on the product packaging. Although Hong Kong currently does not have relevant legislation, if eczema sufferers or individuals with allergies inadvertently purchased those products and become overly exposed to the said substances, there is a chance that they may develop symptoms such as allergic contact dermatitis and rashes. The Council urges suppliers to enhance their quality control and product labelling, to uphold consumers’ rights to accurate information for making informed choices.
The 17 models tested by the Council were mostly purchased from department stores, retail outlets and beauty product specialty shops, with the retail price per item ranging from $101 to $1,580, equivalent to unit price per millilitre or per gram ranging from $3.4 to $52.7, a whopping difference of more than 14 times. However, test results showed that the highest and lowest priced models received the same highest overall score (5 points), reflecting that there is a good range of selections on the market regardless of price. This test mainly covered the ascorbic acid content of the models, i.e. the vitamin C concentration. As for the content of other vitamin C derivatives, since there is currently no relevant test method that is deemed accurate for all the vitamin C derivatives, it was not included in the current test programme. Furthermore, since the skincare efficacy of products would vary depending on the overall formula used, for the sake of fairness, the test score was based on the discrepancy between the detected vitamin C concentration and the product labelling, instead of being a direct score on the vitamin C concentration.
Vitamin C Concentrations of 10 Models Lower than Labelled
1 Model Had None Detected
Vitamin C is most commonly known for its antioxidant properties. Normal skin would contain a certain concentration of vitamin C to promote the production of collagen in the skin, hence many skincare products in recent years would use vitamin C as a selling point. The test results showed that 1 out of the 17 samples was not detected with any vitamin C at all, while the remaining samples had a concentration ranging from 0.66% to 13%. 12 models had provided their claimed vitamin C concentration information on the packaging, ranging from 6% to 15.2%, but the test results of 10 models indicated that their actual concentrations were 0.2% to 6% lower than as stated on their packaging, whereas 1 model‘s concentration was 1% higher. Nearly 30% of the models (5 models) did not state their vitamin C concentration on the packaging.
According to overseas studies, vitamin C concentrations ranging from 10% to 20% could enhance skin penetration and increase stability, hence achieving the effects of whitening and lightening spots. 5 samples were found with vitamin C concentration ranging from 11% to 13%, another 4 were close to 10%, considered to be within the ideal range. However, higher levels of vitamin C concentrations are not necessarily better, as common studies have shown that if the vitamin C concentration exceeds 20%, the chance of skin irritation would increase.
7 Models Detected with Fragrance Allergens Yet Some Lacked Labelling
Many cosmetics and skincare products are added with fragrances to enhance their scent. All tested models did not contain fragrance allergens prohibited by the EU, but over 40% (7 models) were found to contain a total of 7 fragrance allergens with restricted use in the EU, with the more common ones including limonene (5 models) and linalool (4 models), with concentrations exceeding the upper limit permitted under the EU Cosmetics Regulation (0.001%) for labelling of such ingredient on the product packaging, but only 3 provided labelling information for all or some of the detected allergens. If eczema sufferers or individuals with allergies inadvertently purchased those products and became overly exposed to such substances, there is a chance that they may develop symptoms such as allergic contact dermatitis and rashes.
Products that are too acidic or too alkaline can also cause irritation, and even cause damage to the skin. As defined under the EU’s Regulation on Classification, Labelling and Packaging of Chemical Substances and Mixtures, substances with a pH lower than 2 or higher than 11.5 are considered corrosive, with the possibility of causing chemical burn to the skin. The pH of the 17 models ranged from 2.7 to 6.4, all within the safe range, among which 10 models had a pH of 3.5 or below. Research indicated that a lower pH (3.5 or less) would increase the stability of ascorbic acid and enhance the lipid solubility of the product for easier absorption by the skin.
Urged to Improve Transparency in Labelling Information
The concentration of vitamin C would decrease upon exposure to air, moisture and light, thus affecting the product’s efficacy, hence consumers should pay special attention to a product’s manufacturing date, concentration, expiry date before or after opening the packaging, etc. However, the review found that 1 model had no expiry date, and another 6 models did not provide a detailed list of ingredients in English or Chinese, which indicated that information transparency was far from satisfactory. If a product contained allergenic substances or preservatives, the manufacturer should clearly label them, so that eczema sufferers or persons with allergies would not inadvertently use the product with harmful results. Furthermore, higher concentrations of vitamin C could also cause allergic reactions, thus a warning message is essential to remind consumers that if they feel unwell after use, they should stop using the product immediately and consult a healthcare professional. However, 3 models had no such warnings on the packaging. The Council urges manufacturers to proactively improve the labelling on the packaging to safeguard the health of consumers.
Consumers may refer to the following when using skincare products that contain vitamin C to achieve the desired results:
- Thoroughly cleanse the skin of the face before use. Use once to twice daily in the morning or evening, taking an appropriate amount each time, and adjust the frequency of use according to the skin’s condition and the product’s recommendations;
- If used in conjunction with products containing acids, vitamin A, or vitamin B3 in high concentrations, there may be an increased chance of skin irritation;
- Although skincare products with vitamin C can protect the skin from ultraviolet (UV) rays, they are not a substitute for sunscreen products;
- Store products with vitamin C in a cool and dry place away from direct sunlight. Consumers may also consider selecting products of small volume or those packaged in airtight or tinted glass bottles;
- For consumers with history of skin allergies, it is advisable to try a skincare product with a lower concentration of vitamin C on a smaller area of skin to see if there is any allergic reaction, or consult a healthcare professional;
- After high-intensity skin treatments, the skin may be in a more fragile condition and be more susceptible to dryness and sensitivity. During this time, consumers should refrain from using skincare products with high concentrations of vitamin C or other stimulants;
- In addition to applying skincare products, consuming sufficient vitamin C through daily diet is essential for maintaining fair and healthy skin.
Download the article (Chinese only): https://ccchoice.org/576-vit-c
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