Homemade chemical solutions for skin care need to be handled carefully to ensure safety and effectiveness. The following are some common and relatively mild ingredients, but please **Be sure to follow the following principles**： --- ###**Safety principles** 1. **Avoid high-concentration or irritating ingredients**: Skin is sensitive, and improper use may cause burns or allergies. 2. **First local test**: Test in a small area on the wrist or behind the ear for 24 hours. 3. **Consult a professional**: Serious skin problems (such as infections and eczema) require medical attention, and homemade products cannot be relied on. 4. **Compliance with regulations**: Some ingredients may be subject to regional regulations. --- ###**Classification and use of commonly used ingredients** #### 1. **Antibacterial/anti-inflammatory ingredients** -**Tea Tree Oil (Tea Tree Oil)**: Natural antibacterial, suitable for acne (need to be diluted to 1-2%, not in direct contact with the skin). -**Niacinamide (Niacinamide)**: Anti-inflammatory, oil control, suitable for acne and redness (concentration recommended 1-5%). - **Azelaic Acid (Azelaic Acid)**: Anti-acne, lighten pigmentation (professional guidance is required, the concentration is usually less than 10%). #### 2. **Moisturizing and repairing** -**Glycerin (Glycerin)**: Basic moisturizer, can be diluted and used (5-10% concentration). -**Hyaluronic Acid (Hyaluronic Acid)**: Deep moisturizing (0.1-1% soluble in water). -**Panthenol (Panthenol, vitamin B5)**: Repairs the barrier and relieves dryness (1-5%). #### 3. **Soothing and anti-allergic** -**Aloe Vera Gel (Aloe Vera Gel)**: Natural anti-inflammatory, relieves sunburn or sensitive skin (pure gel without additives required). -**Chamomile Extract (Chamomile Extract)**: Soothes redness and swelling, can be used with cold compresses. #### 4. **pH regulator** -**Lactic Acid (Lactic Acid)**: Gently exfoliate and adjust the pH (the recommended household concentration is ≤5%). -**Citric Acid (Citric Acid)**: Micro-adjust the pH of the solution (0.1-0.5%). #### 5. **Auxiliary solvent** -**Distilled water/pure water**: As the basic solvent, avoid impurities. -**Ethanol (alcohol)**: Only used for disinfection tools (avoid direct contact with the skin, which may irritate). --- ###**Formula example (basic moisturizing spray)** -**Ingredients**： -90ml distilled water -Glycerin 5ml -Aloe Vera Gel 5ml -1 drop of tea tree essential oil (need to be fully mixed) -**Usage**: Shake well and spray on the cleaned skin, avoiding the eye area. --- ###**Mixed ingredients are strictly prohibited** -**Acidic ingredients (such as salicylic acid) + alkaline ingredients (such as baking soda)**: Irritation may occur. -**Essential oils + high concentration of alcohol**: Destroys the skin barrier. -**Vitamin C+metal ion**: Oxidation failure. --- ###**Important reminder** -**Do not prepare your own medicines**: Medical prescription ingredients (such as clotrimazole and clindamycin) are required to treat fungal or bacterial infections. -**Avoid Internet folk remedies**: Such as high concentrations of vinegar, lemon juice, etc. may damage the skin. -**Priority is given to commercially available products**: Regular skin care products have been tested for safety, and the risk of self-production is higher. If your skin problems persist or worsen, please seek medical attention in time! Safety always comes first.