I have found information on five different skin brightening serums. Here are the details, positive and negative aspects, and ingredients or materials of each product:

1. Skin Actives Skin Brightening Serum:

• Ingredients: Water, Niacinamide, Acetyl Glucosamine, Lactobacillus/Kelp Ferment Filtrate, etc.
• Positive aspects: Multi-functional skincare superstar with several proven benefits for the skin, great anti-aging, wrinkle smoothing ingredient, fades brown spots alone or in combination with amino sugar, acetyl glucosamine.
• Negative aspects: None found.
• Other details: The water used in cosmetics is purified and deionized.

2. Barefaced Brightening Serum:

• Ingredients: Kojic Acid, Arbutin, Azelaic Acid, Bearberry, Licorce Root, Vitamin E, Hyaluronic Acid, etc.
• Positive aspects: Reduces the appearance of stubborn dark spots, formulated with brightening ingredients that are clinically proven to minimize skin discoloration.
• Negative aspects: None found.
• Other details: Formulated without parabens, fragrance, phthalates, sulfates, artificial dyes, mineral oil, formaldehyde donors.

3. Reviva Labs Dark Spot Brightening Serum:

• Ingredients: 5% Niacinamide, 1% Glycolic Acid, 1% Arbutin, 1% Kojic Acid, etc.
• Positive aspects: Diminishes the appearance of age & dark spots and visibly improves uneven skin tone.
• Negative aspects: Contains alpha hydroxy acid (AHA) that may increase your skin’s sensitivity to the sun and particularly the possibility of sunburn.
• Other details: Patch test for sensitivity on the underside of the arm. This product is not recommended for use on children under 12 years of age. Do not use on the eye area or over cuts or irritations.

4. Urban Skin Rx Super C Brightening Serum:

• Ingredients: Vitamin C, Kojic Acid, Ferulic Acid, Salicylic Acid, etc.
• Positive aspects: Combines Vitamin C, Arbutin and Kojic Acid to improve the appearance of dark marks, uneven skin tone and aging skin, hyaluronic acid hydrates and smooths, salicylic acid cleanses pores.
• Negative aspects: None found.
• Other details: Formulated without parabens, fragrance, phthalates, sulfates, artificial dyes, mineral oil, formaldehyde donors.

5. Ursa Major Brighten Up Vitamin C Serum:

• Ingredients: Ascorbic Acid Polypeptide, etc.
• Positive aspects: Contains a potent and long-lasting form of vitamin C that brightens and smooths skin’s tone and appearance, while providing instant hydration.
• Negative aspects: None found.
• Other details: Formulated without petrochemicals, sulfates, parabens, synthetic fragrances, or other suspect chemicals.

Overall, all of these serums contain ingredients that are beneficial for brightening the skin. It is important to note that some of the products contain acids that may increase sensitivity to the sun, so it is recommended to use sunscreen and limit sun exposure while using these products.