How to formulate for sensitive skin: A step-by-step guide

Have you ever experienced stinging, itching, or redness after using a new product or even just stepping out into the wind? If so, you’re not alone!

Sensitive skin is a common concern, and learning how to formulate products that genuinely care for it is an incredibly empowering skill to have as a cosmetic formulator.

In this post, we’ll explore what sensitive skin is, examine the crucial role of the skin barrier, and look at the top ingredients to use – and avoid – when formulating for this unique skin type. By the end of the post, you’ll have a strategic, scientific mindset that will help you design truly effective and soothing formulations. Let’s get started!

What is sensitive skin?

Let’s start by defining what we mean by sensitive skin. Sensitive skin is characterised by an increased reactivity to factors that would not typically cause discomfort.

These sensitising factors can come from various sources, including environmental triggers like UV radiation, heat, or wind, as well as skincare products containing certain ingredients that are more commonly known to cause irritation, such as surfactants, fragrances, or acids.

Even stress can play a role. When exposed to these triggers, the skin often reacts with sensations such as stinging, tingling, burning, itchiness, and redness. While this irritation isn’t always visible, the underlying skin barrier is frequently compromised.

Common signs of sensitive skin

Skin reactivity isn’t always the same; it can manifest in two ways:

1. Irritation: This is an immediate, localised inflammatory response, typically appearing as redness or a stinging sensation after exposure to a triggering substance.
2. Sensitisation: This is an immune-mediated response that builds over time. Repeated exposure to a particular ingredient can eventually lead to an allergic reaction.

Why does it happen?

Sensitive skin isn’t a single condition but rather the result of several overlapping mechanisms. Often, people with sensitive skin have a weakened skin barrier, which lets irritants and microbes through more easily and increases water loss, leaving skin dry and reactive.

Some people also have nerves that over-respond, creating sensations of burning, stinging, or itching, while others show a stronger immune response or blood vessels that flush too readily. Together, these factors make the skin less resilient and more prone to discomfort.

Why some people experience this more than others depends on many factors. Genetics can play a role, as can skin type: fair or dry skin types are usually more reactive.

Exposure to environmental stressors like wind, UV, or pollution, as well as lifestyle habits, can also compromise the skin. Ageing and underlying conditions like eczema or rosacea also increase the likelihood of sensitivity.

The role of the skin barrier

Understanding the skin barrier is absolutely fundamental when it comes to formulating for sensitive skin.

The skin barrier is the outermost layer of your skin (the stratum corneum), and its integrity plays a crucial role in overall skin health. It is a dynamic system of lipids, proteins, and cells that works to balance protection with permeability. When the skin barrier is intact, it maintains hydration and shields the skin from irritants, microbes, and allergens.

With sensitive skin, even small changes in barrier structure – such as reduced ceramides or disrupted lipid organisation – can tip the balance. This doesn’t just let external stressors in; it also heightens nerve activity and immune responses underneath, amplifying sensations like stinging or redness. It also means water can escape from the skin more quickly – leaving it drier, more irritated, and even more sensitive.

You can learn more about how the skin barrier works in this guide below:

Skin barrier 101: Essential guide for natural cosmetic formulators

How to formulate for sensitive skin

Formulating for sensitive skin is all about achieving a balance between soothing and strengthening agents. You want gentle ingredients that calm and strengthen the skin, helping the barrier repair itself and stay protected.

But just as important as what you add to your formulations is what you leave out. Avoid anything that might irritate the skin and make sure all the ingredients work well together.

Here are the key aspects to keep in mind when formulating for sensitive skin:

1. Keep it simple: Less is more. A streamlined formula with just the essentials is easier to test, adjust, and be gentle on the skin.
2. Check the pH: The acidity of your product matters. Aim for a skin-friendly range, around 4.5 to 5.5, so the product feels comfortable and doesn’t irritate the skin.
3. Think stability: Even the best ingredients won’t help if your formulation falls apart. An unstable formula can separate, change texture, or degrade active ingredients, which may increase the risk of irritation or reduce the product’s safety.
4. Use the right preservative: Preservatives are essential to keep your product safe and free from microbial contamination. But they can also be a source of irritation if chosen poorly. The right preservative doesn’t just protect your formulation; it also helps ensure your formulation product stays gentle, stable, and suitable for sensitive skin.
5. Skip common irritants: This is especially important. Further in this post, we’ll cover ingredients to avoid when formulating for sensitive skin.

Best ingredients for sensitive skin

When formulating for sensitive skin, your ingredient choices matter most. Focus on soothing discomfort, supporting the skin barrier, and preventing flare-ups in the future.

Prioritise the use of gentle, evidence-based ingredients. Look for those that calm and soothe the skin, support and strengthen the barrier, and reduce visible redness and discomfort.

Here’s a helpful post on how to best research your ingredients:

How to research cosmetic ingredients for organic skincare

Beginner-friendly ingredients

Below are some examples of beneficial ingredients for sensitive skin that are accessible to beginner formulators:

• Aloe vera: Aloe vera is one of the most well-known skincare ingredients out there, renowned for its unique composition and soothing properties. Thanks to its ability to form a protective film on the skin, it is often used in formulations to calm irritation and repair the skin. You can find out more about aloe in this post.
• Calendula and chamomile: These gentle botanicals are reputed to ease redness and irritation. You can learn more about calendula in this dedicated post and chamomile in this post.
• Colloidal oatmeal: Oatmeal is a classic ingredient for comfort and softness. We cover everything about oats in our Oats Mini Lab, which is part of our exclusive membership site, the Lab at Formula Botanica.
• Emollients: Emollients like vegetable oils and fatty acids can help reinforce the skin barrier and lock in moisture. You can find many types of oils on our blog.
• Humectants: Humectants like glycerine or hyaluronic acid draw water to the skin and keep it hydrated. Learn more about hyaluronic acid here.
• Microbiome-friendly ingredients: Your skin has its own natural community of “good” bacteria that help keep it balanced. When this balance is disturbed, skin can become more reactive. Ingredients that support a healthy microbiome, such as certain fermented extracts, can help keep sensitive skin calm and resilient. Learn more about the skin microbiome in the Microbiome Mini Lab.

High-performance ingredients

If you’re a more advanced formulator, you can also consider these ingredients:

• Allantoin: Allantoin is a soothing and moisturising ingredient known for helping skin stay soft and comfortable. It supports skin hydration by reducing dryness and roughness, while calming minor irritations, making it especially beneficial for sensitive skin formulations.
• Alpha-bisabolol: This compound, derived from chamomile, is excellent for calming inflammation and reducing discomfort.
• Ceramides: Ceramides are waxy lipid molecules that occur naturally in the skin. Think of them as the mortar between the bricks of your skin cells. Along with cholesterol and fatty acids, ceramides form the skin’s protective barrier, helping to lock in moisture and shield against environmental stressors. Learn more about ceramides here.
• Niacinamide: Vitamin B3, or niacinamide, is a multi-tasking ingredient that helps calm inflammation and supports healthy skin barrier function. It pairs well with hyaluronic acid to support hydration and barrier function. Find out more about vitamin B3 in this post.
• Panthenol: Panthenol, or pro-vitamin B5, is known for its soothing and skin-repairing effects. Panthenol helps reduce discomfort and promote skin repair. Combining it with allantoin can boost these benefits.

We cover all these high-performance ingredients and how to formulate with them in our Advanced Diploma in Organic Cosmetic Science.

Ingredients to avoid

Just as important as what you add to your formulations is what you leave out. Sensitive skin benefits from gentle, non-reactive formulations. Try to avoid:

• Fragrances and essential oils: These are among the most common triggers of stinging, redness, or flare-ups. Certain essential oils (such as citrus oils) can also cause photoxicity, or increase photosensitivity, making the skin more reactive to sunlight.
• Drying alcohols (ethanol/denatured alcohol): These can strip away natural moisture and compromise the barrier, leaving skin feeling tight and irritated.
• Strong exfoliants: Harsh scrubs with large particles or very high concentrations of acids can weaken the barrier and worsen sensitivity.
• Sulphates: These foaming agents can be overly aggressive, disrupting the barrier and provoking irritation, especially in facial or leave-on products.
• Known allergens and sensitisers: Some ingredients are more likely to cause allergic reactions with repeated exposure. These include certain components present in preservatives, in fragrance compounds, and in botanical extracts. Many of the common fragrance allergens identified by IFRA (the International Fragrance Association), such as limonene, linalool, cinnamal, and eugenol, are also worth avoiding in sensitive skin formulations. Other ingredients that are best avoided in formulations for sensitive skin are cyes and colourants, known to potentially increase the risk of irritation. You can find more about allergens and sensitisers here.

Final thoughts

Formulating for sensitive skin is both an art and a science. It requires care, precision, and above all, an understanding of how every ingredient interacts with the skin. It’s not just about what you add, it’s about how your choices work together to create harmony.

Sensitive skin comes with unique needs. Its barrier is often more fragile, it reacts more easily, and it can show signs of stress more quickly. By recognising these traits and choosing ingredients thoughtfully, you can design formulations that are not just gentle but also stable, effective, and purposeful.

If you’d like to learn more about sensitive skin and how to formulate for this skin type, check out the Sensitive Skin Mini Lab, available in your Lab membership.

And if you’ve never formulated skincare before, check out Formula Botanica’s free training and learn how to make your own organic skincare from scratch!

FAQ

• What is sensitive skin?

Sensitive skin is a skin type that reacts more strongly than usual to things that wouldn’t normally cause discomfort, such as weather changes, skincare products, or stress. This often happens when the skin barrier is weaker, making the skin more prone to irritation. Common signs can include stinging, tingling, burning, itchiness, or redness.

• What are the best ingredients for sensitive skin formulations?

For sensitive skin, gentle, barrier-supporting ingredients are best. Look for soothing ingredients (like panthenol, colloidal oatmeal, calendula, or chamomile), hydrating ingredients (like glycerine or hyaluronic acid), and barrier-repair ingredients (like vegetable oils, fatty acids or ceramides).

If you’re a more advanced formulator, high-performance options like niacinamide, alpha-bisabolol or fermented extracts can also be useful.

• What ingredients should I avoid in sensitive skin formulations?

It’s best to avoid common triggering ingredients such as fragrance and essential oils (especially UV-reactive citrus oils), drying alcohols (like ethanol or denatured alcohol), harsh scrubs or strong acids, and sulphates (like SLS or SLES). These can strip the skin barrier and make sensitivity worse.

• How to formulate for sensitive skin?

Keep it simple: choose gentle ingredients that soothe, hydrate, and protect, while avoiding unnecessary extras that could irritate. Also, pay attention to pH, stability, and preservation so your formulation remains safe, stable, and effective over time.

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Eliziane Pozzagnolo

Eliziane is a Pharmacist and Biochemist, manages our Student Experience Team and provides technical advice for the ingredients research we undertake and provide. She loves bringing together the concepts of science, sustainability and organics. Read more about the Formula Botanica team.