What the research says about residue, coating and scalp balance

If your hair feels heavy, flat, coated or dull even after washing, your conditioner might not be “too rich” — it might be creating build-up.

Conditioner build-up is widely discussed online, but what does the science actually say? Research into hair fibre chemistry and cosmetic formulation shows that certain conditioning agents are designed to deposit onto the hair surface. That is how they reduce friction, improve shine and increase softness.¹ ²

The issue is not that conditioners deposit. It is that repeated deposition without proper removal can accumulate over time.

In this blog, we break down what build-up really is, why it happens, and what you can do about it.

 

What is “build-up” scientifically?

Hair fibres have a negatively charged surface when wet. Many conditioning ingredients are positively charged (cationic). This opposite charge attracts the conditioning molecules to the hair shaft, allowing them to adhere to the cuticle.¹

Common conditioning agents that deposit include:

• Cationic surfactants such as behentrimonium chloride
• Cationic polymers such as polyquaterniums
• Silicones such as dimethicone
• Fatty alcohols used for slip and softness

This deposition is intentional and beneficial in controlled amounts. It reduces friction, improves combability, and protects the cuticle from mechanical damage.¹ ³

However, research in cosmetic chemistry shows that repeated application of film-forming agents can lead to cumulative surface coating if not periodically removed.²

A note on silicones

Silicones such as dimethicone are widely used in hair care because they create smoothness, reduce friction and improve shine. They are considered safe for cosmetic use within regulatory limits.³

However, some research has raised broader questions about certain cyclic silicones and their potential environmental persistence and possible endocrine-disrupting activity in laboratory settings.⁶ ⁷

While regulatory authorities continue to assess and monitor these compounds, and many commonly used silicones are considered low risk in rinse-off products, we choose not to use silicones in our formulations. This is based on a precautionary approach, both environmentally and in relation to emerging research around bioaccumulation and endocrine signalling.

This does not mean silicones are inherently harmful in all contexts. It reflects our preference for lightweight conditioning systems that rinse clean without long-term film formation.

How build-up happens

Build-up usually develops gradually.

Each wash deposits a small amount of conditioning material. Over time, especially if:

• You co-wash frequently
• You use heavy masks regularly
• You apply conditioner close to the scalp
• You rarely clarify

That thin layer can thicken.

Studies on silicone deposition show that certain non-water-soluble silicones can remain on the hair fibre until removed with stronger surfactants.⁴

The issue is balance.

What build-up feels like

Build-up does not usually look dramatic. It often feels like:

• Hair that feels coated even when clean
• Reduced volume at the roots
• Conditioner that seems to “stop working”
• Difficulty absorbing moisture

Some research suggests that excessive surface coating can reduce moisture movement into the fibre over time.²

Again, this depends on formulation and washing habits, not a single ingredient.

Scalp build-up is slightly different

When conditioner is applied directly to the scalp, especially rich or occlusive formulations, residue can combine with:

• Sebum
• Dead skin cells
• Styling products

This can create a film across the scalp surface.

Dermatological literature notes that heavy occlusion on the scalp may contribute to irritation in susceptible individuals, particularly when combined with infrequent cleansing.⁵

The key word is susceptible. Not everyone experiences this.

Why stronger shampoo is not always the answer

It might seem logical to solve build-up with very strong cleansers. However, harsh surfactants can strip the scalp barrier and lead to dryness or rebound oil production.¹

The goal is not aggressive removal. It is balanced cleansing.

Periodic clarification using an appropriate surfactant system can remove accumulated film without disrupting scalp comfort.

How to prevent conditioner build-up

Based on cosmetic science and dermatology research:

• Apply conditioner mainly to mid-lengths and ends
• Use lighter formulas if hair is fine
• Clarify periodically if you use film-forming products
• Avoid layering multiple heavy stylers

Understanding how deposition works helps you use conditioners strategically rather than reactively.

DIY gentle clarifying rinse

If your hair feels coated and you want a simple reset, you can try this:

Apple cider vinegar rinse

Mix:
• 1–2 tablespoons apple cider vinegar
• 250 ml water

After shampooing, pour slowly over the scalp and lengths. Leave for 1–2 minutes, then rinse thoroughly.

Why it can help:

Vinegar is mildly acidic. Acidic rinses can help smooth the cuticle surface and may assist in removing certain mineral and product residues by altering surface charge interactions.¹

Use no more than once every 1–2 weeks. Overuse may cause dryness.

If your scalp is sensitive, patch test first or skip this method.

The important distinction

Conditioner build-up is not proof that conditioners are bad.

It is proof that conditioners are designed to deposit.

When deposition exceeds removal, build-up can occur.

When balanced correctly, conditioning protects hair, improves manageability, and reduces breakage.¹ ³

Why this matters

If your hair feels heavy or dull, switching brands repeatedly may not solve the issue.

Understanding how conditioning chemistry works often matters more than buying something new.

Sometimes the solution is not stronger or more nourishing.
It is lighter, more targeted, or used differently.

Hair care works best when it is informed, not reactive.

References

1. Robbins, C.R. (2012). Chemical and Physical Behavior of Human Hair. Springer.

2. Draelos, Z.D. (2010). Conditioner technology and film formation. Journal of Cosmetic Dermatology, 9(3), 221–228.

3. Bolduc, C., & Shapiro, J. (2001). Hair care product mechanisms. Clinics in Dermatology, 19(4), 431–436.

4. Tadini, K.A. et al. (2009). Silicone deposition characteristics. International Journal of Cosmetic Science, 31(4), 273–283.

5. Misery, L. et al. (2018). Sensitive scalp and irritation mechanisms. International Journal of Trichology, 10(5), 187–193.

6. Wang, D. et al. (2013). Endocrine-disrupting potential of cyclic siloxanes. Environmental Science & Technology, 47(21), 12674–12681.

7. European Chemicals Agency (ECHA). (2018). Assessment of D4 and D5 cyclic siloxanes under REACH regulation.