Color Theory in Sunless Tanning: Why It Sounds Right But Does Not Work

Let Us Talk About the Trend Everyone Is Talking About

If you are a spray tan artist, you have probably seen this advice:

• Cool undertone? Use a green-based bronzer
• Warm undertone? Reach for violet
• Neutral? Try blue-green

It sounds professional. It feels personalized. For many spray tan professionals, it serves as a helpful starting point for learning how to customize tans.

However, if you have ever followed these charts and still ended up with unexpected or uneven results, there is a reason for that.

Color theory sounds scientific, but when applied to spray tanning, it often misleads professionals away from how DHA truly reacts with skin.

Color theory may sound right, but it does not reflect how DHA actually works within the skin.

My Perspective: From High-End Color Cosmetics to Skin Science

Before I launched AYU Sunless, I spent many years working in professional formulation labs as a cosmetic chemist. During that time, I developed a wide range of personal care products, including high-end color cosmetics, facial and body care products, and skin treatments for prestige brands.

I worked closely with other cosmetic chemists to create foundations, lipsticks, powders, and tinted products. In that world, undertones absolutely matter because the goal is to match or enhance the visible surface of the skin using pigment.

However, when I began working in sunless tanning formulation, I noticed that many brands  and professionals were applying makeup logic to a process that is fundamentally chemical and biological in nature.

As more companies entered the sunless tanning market, often as marketers rather than formulators, many began using makeup-based color theory to differentiate themselves. It sounded technical, even scientific, but lacked consistency. In color cosmetics, color theory is rooted in pigment and has a clear, standardized purpose. However, in sunless tanning, that same logic falls apart. Some brands associate specific bronzer colors with certain DHA percentages. Others tie them to different skin types entirely. 

"If color theory truly applied to DHA-based tanning, would it not follow the same rules across the industry?"

Sunless tanning is not about covering the skin. It is about how DHA reacts with the skin to develop a tan from within. That is where the science takes over.

What Actually Happens During a Spray Tan?

The active tanning ingredient in all professional and at-home sunless tanning products is DHA, or Dihydroxyacetone.

Once applied, DHA reacts with amino acids in the stratum corneum, the outermost layer of the skin, through a natural process known as the Maillard reaction. This creates a temporary pigment within the skin itself.

The final tan color is influenced by:

• The skin’s natural amino acid composition
• Hydration levels and the condition of the skin barrier
• The pH of the skin at the time of application
• The concentration of DHA used in the formula
• The amount of time left before rinsing, if using a rapid tan

No where in that list does skin undertone play any role.

"This is why two clients with similar visible undertones can develop two completely different tans. The result depends on skin biology, not surface-level color correction."

👉 To learn how supporting the skin itself improves color development and longevity, read our article on skincare-infused spray tanning.

What Do Bronzers Actually Do?

Bronzers are cosmetic pigments, often made using FD&C dyes or caramel, blended into the sunless tanning solution to provide temporary, visible color.

They serve several useful functions:

• Helping artists see even application coverage
• Giving clients an immediate bronzed appearance
• Adding depth to the initial look before the tan develops

However, bronzers rinse off during the first one or two showers. They do not determine how the tan will develop or fade.

This is why we always explain to our professional clients that bronzer is a temporary solution. What remains after rinsing is the DHA-based tan. How that tan develops depends entirely on the client’s skin chemistry, not the color of the bronzer.

Some brands also market “color drops” as undertone adjusters. These drops may slightly shift the bronzer appearance, but they do not react with the skin or influence DHA development. Like bronzers, they rinse off and have no long-term effect on the final result.

When Bronzers “Stain” the Skin-Why That’s Not a Good Thing

In the professional sunless tanning world, some artists believe the bronzer in their solution helps “tint” or “stain” the skin for a few days.

That idea sounds harmless, but scientifically and legally, it’s not how bronzers are meant to behave.

The cosmetic colorants used in bronzers, typically FD&C and D&C dyes, are approved only for temporary surface use.

They are water-soluble and designed to rinse off with the first shower, leaving behind the true developed color created by Dihydroxyacetone (DHA) through the Maillard reaction in the skin’s outermost layer.

If a bronzer appears to “stick” or stain the skin for several days, it often means:

• The skin is dry or unevenly exfoliated, trapping the color on the surface.
• The formula contains excessive dyes or ingredients that cause residue buildup.
• The pH or solvent system allows abnormal dye adhesion, which is not ideal and may compromise compliance.

Under FDA regulations, color additives are certified for specific intended uses and exposure durations.

FD&C and D&C colorants cannot be used to create a lasting color change on the skin, because that effect belongs only to DHA, which is separately regulated as a skin-color additive.

Any bronzer that intentionally stains or alters the skin beyond its cosmetic, rinse-off purpose would cross a regulatory line and could raise labeling, safety, and liability concerns for a manufacturer.

In short:

👉 Bronzers are for guidance and instant color.

👉 DHA is for lasting tan development.

The two serve completely different purposes, and when used correctly, they work in harmony to create even, natural, and compliant sunless tanning results.

How We Formulate Bronzer Tones at AYU

At AYU, we offer multiple tanning solutions, not to match undertones, but because each formula contains a unique blend of ingredients that interacts differently with DHA. This affects how the tan develops and fades. The bronzer tone in each formula is adjusted only to complement the base formula, especially when ingredients like botanical extracts naturally influence color. We focus on brown-toned bronzers that look flattering on most skin types and transition cleanly as the tan appears.

This approach ensures the bronzer:

• Looks natural during application

• Does not interfere with DHA development

• Fades evenly as the skin’s natural tone appears
  

What Actually Affects the Final Tan?

Several real factors influence how a tan develops and fades, none of which are related to undertone:

• Skin preparation and hydration
• DHA concentration in the formula
• Rinse timing and product layering
• Barrier health and skin resilience
• The client’s natural skin cycle and exfoliation habits

Color theory does not account for any of these factors. However, your professional experience and the proper educational support can absolutely help you account for them.

Our Responsibility to Support You

At AYU, we are not here to correct you. We are here to support you.

We sincerely appreciate the artistry, dedication, and care that spray tan professionals bring to every client. Our role, as cosmetic chemists and manufacturers of skin care–infused sunless tanning products, is to provide you with the tools, formulas, and education you need to deliver consistent results, rooted in real skin science.

That is why we focus on:

• Balanced DHA ranges that suit different skin types
• Skin care–infused ingredients that support the barrier and extend the life of the tan
• Neutral-to-warm brown bronzers that work beautifully across diverse skin tones
• Clear, respectful education that builds your confidence and trust in the process

If color theory helped you get started in your spray tanning journey, that is understandable. It provided many professionals with a way to explain personalization.

However, if you have ever felt confused, frustrated, or uncertain when your color chart did not deliver the expected result, please know this:

It is not you.

The system needs to be upgraded.

We are here to offer that upgrade with humility, skin science, and support that honors both your artistry and your client’s skin.

Want to go deeper?

Explore more science-backed articles on our Sunless Smart™ blog, or browse AYU’s professional tanning solutions, designed with skin care, not just color theory, in mind.
Have questions or want to share your experience? Send us a message