Lesson 1: What is DIY Skincare? Understanding the Basics of Cosmetic Formulation

What is DIY Skincare? A Science-Based Approach to Formulating Your Own Skincare Products

In recent years, DIY skincare has gained popularity as more people seek control over what they put on their skin and hair. Consumers are becoming more conscious of ingredient transparency, environmental safety, and customization, leading to a surge in interest in homemade skincare products. But DIY skincare is more than just mixing oils and butters—it’s a science that requires a solid understanding of formulation principles.

I started this way too. My first experiments were sugar scrubs with honey, food coloring, and fragrance oils—fun, but a learning experience nonetheless. I still remember making a lemon-based face toner (a bad idea, by the way). It wasn’t until I saw mold growing in one of my sugar scrubs that I realized something was missing from my homemade products. That curiosity led me deeper into cosmetic formulation, and I quickly learned that effective skincare isn’t just about throwing ingredients together—it’s about understanding how they interact, ensuring stability, and making safe, effective products.

But before we dive into proper formulation, let’s address some of the biggest misconceptions about DIY skincare.

Common Misconceptions About DIY Skincare

🚫 Myth #1: DIY Skincare is Just Mixing Natural Ingredients
✔ Reality: While it’s true that many DIY recipes focus on natural ingredients, true cosmetic formulation goes beyond that. Effective skincare requires an understanding of ingredient interactions, emulsification, preservation, and stability.

A product might look good at first, but if it’s not properly formulated, it can separate, spoil, or cause irritation within days or weeks.

🚫 Myth #2: Natural Skincare Doesn’t Need Preservatives
✔ Reality: Any product containing water, aloe vera, hydrosols, or any water-based extracts MUST have a preservative.

A common mistake in DIY skincare is thinking that ingredients like essential oils, vitamin E, or honey can prevent microbial growth. They don’t. Any product that contains water (or comes into contact with water) is at risk of growing bacteria, yeast, and mold.

Example:

• A homemade face mist without a preservative might look fine, but within a week, unseen bacteria and mold can develop—even if stored in the fridge.
• A DIY lotion without preservatives can become contaminated the moment you dip your fingers into the jar.

If you want your formulations to be safe and long-lasting, proper preservation is a must.

🚫 Myth #3: If It’s Safe to Eat, It’s Safe for the Skin
✔ Reality: Just because something is edible doesn’t mean it’s safe for topical use.

A common DIY mistake is assuming that ingredients like lemon juice, baking soda, apple cider vinegar, and coffee grounds are good for skincare just because they’re “natural” or “food-grade.” But your skin isn’t your stomach.

Here’s why this thinking is flawed:

• Lemon juice is highly acidic (pH ~2), which can damage the skin barrier, cause burns, and lead to hyperpigmentation.
• Baking soda is too alkaline (pH ~9), which disrupts the skin’s natural pH balance, leading to irritation and dryness.
• Coffee grounds are too abrasive for regular facial exfoliation, leading to microtears in the skin.

Skincare ingredients need to be formulated at the right pH and concentration to be effective and safe. This is why proper formulation knowledge is key.

Why DIY Skincare Has a Bad Reputation (And How to Do It Right)

Unfortunately, DIY skincare has gotten a bad reputation—not because making your own skincare is inherently bad, but because many DIY recipes floating around online lack scientific backing.

Poorly formulated DIY skincare can result in:
❌ Skin irritation or allergic reactions due to improper ingredient combinations.
❌ Contamination & microbial growth from a lack of proper preservation.
❌ Ineffective products because ingredients aren’t formulated correctly for skin absorption.

But when done correctly, DIY skincare can be a powerful, rewarding, and customizable way to take control of your skincare routine.

That’s why I created this science-based formulation series—to help you create safe, effective, and professional-grade skincare products at home.

What Makes a Good Skincare Formula?

A well-formulated skincare product isn’t just about what ingredients you use—it’s about how they work together to create a stable, effective, and safe formula.

A Good Formula Should Be:

1. Stable – Doesn’t separate, spoil, or lose effectiveness over time.

• Example: A properly emulsified lotion stays creamy and doesn’t separate into oil and water.

2. Safe – Free from bacterial contamination, unstable emulsions, and ineffective ingredients.

• Example: A water-based serum must have a broad-spectrum preservative to prevent bacterial growth.

3. Effective – Designed with the right active ingredients and pH balance for optimal skin benefits.

• Example: A niacinamide serum needs to be at the right pH (around 5.5–6.0) to remain stable and effective.

4. Customizable – Tailored to your skin type, concerns, and preferences.

• Example: A moisturizer for oily skin should be lightweight and non-comedogenic, while a moisturizer for dry skin should have a richer formula with more emollients.

At The Melalchemist, I focus on science-backed formulation techniques to help you create skincare products that check all these boxes.

How to Start DIY Skincare the Right Way

Now that you know what NOT to do, here’s how to get started properly:

Step 1: Learn the Basics of Cosmetic Ingredients
Before you mix anything, understand what each ingredient does in a formula.

✔ Humectants (like glycerin, hyaluronic acid) draw moisture into the skin.
✔ Emollients (like shea butter, squalane) soften and protect the skin.
✔ Occlusives (like petrolatum, lanolin) create a barrier to prevent moisture loss.
✔ Actives (like niacinamide, vitamin C) target specific skin concerns like hyperpigmentation or acne.

Step 2: Use Proper Tools & Equipment
DIY skincare isn’t cooking—using precise measurements and the right tools is essential.

✔ Digital Scale (0.01g accuracy) – Avoids inaccurate formulations.
✔ pH Meter – Ensures your formulas are skin-safe.
✔ Immersion Blender (or Mini Mixer) – Helps with emulsions and serums.

Step 3: Always Work in Percentages
Skincare formulas should always be in percentages, not “teaspoons” or “cups.”

❌ Bad Example: 2 tbsp Aloe Vera Gel + 1 tsp Honey
✅ Correct Example: Aloe Vera Juice – 70%, Glycerin – 5%, Honey – 5%

Final Thoughts: DIY Skincare Done Right

DIY skincare isn’t just about natural ingredients and fun experiments—it’s about learning proper formulation techniques so you can create safe, stable, and effective skincare products.

✔ If you’re serious about formulating, start thinking like a cosmetic chemist, not just a DIYer.
✔ Always prioritize safety, stability, and skin compatibility.
✔ A well-formulated product will outperform any random DIY recipe you find online.

This blog series is designed to help you learn the fundamentals of formulation so you can start making professional-quality skincare at home.

Up Next: [Lesson 2 – Essential Equipment & Tools for DIY Skincare]

🚀 Let’s get you set up with the right tools for proper formulation!