Deep Conditioning - New and Updated!

Got some news about deep conditioning for you that you're going to like! Why? Because we're in a better position to say why and how something works than ever before.  putting bricks and leopards in your hair will not help

"Deep Condition" usually means we want an extra dose of flexibility, softness, bounce, shine, "life" and detangling ease. But search online for a minute and it can seem like this is going to be an elaborate process. It doesn't have to be, though if you get great results from longer treatments and it works for your lifestyle, and you enjoy it, I wouldn't dare suggest you stop doing that. putting bricks and leopards in your hair will not help

What's in this post: 

What are the main components of conditioners that make deep conditioning more intense? (1)

Where do these work in your hair? (2)

How long does it take for each component to be maximally effective (and what if I want to adjust this for more or less conditioning)? (3)

How do I adjust to make a deep conditioning treatment more or less intense? (4)

1. 

Here we have our main components. They actually come in different shapes and sizes and can have different effects on different areas of the hair.

Oils and emollients: Detangling, softness, smoothing, shine, and increase the ability of conditioners to bind to the surface of hair. This includes the creamy fatty alcohols (Cetyl alcohol, Cetearyl alcohol, Stearyl alcohol) that thicken conditioners and leave a silky feel in hair. And also oils from plants or seeds or nuts. It also includes silicone emollients like Amodimethicone. These ingredients are active at the surface and can move into deeper sections o the hair, depending on the ingredient.

Humectants help moisture (literally talking about water here) stay in the hair longer. They attract moisture. Maybe they increase your dry-time, but they also keeps your hair better hydrated between washes. Many of these ingredients also do some bond-repair, stabilizing hair-proteins to reduce breakage and split ends. Humectants include Glycerin, Propanediol/Propylene glycol, Panthenol, Betaine, Amino acids, Proteins, Peptides, Sodium (or Zinc) PCA, Lactic acid, Aloe vera, Honey, Sorbitol.

Cationic conditioners have a few jobs. They help keep the product from separating (they're emulsifiers). They have a positive electrostatic charge (hence the plus-signs) and bond to the surface of hair - which has more negative electrostatic charges. That reduces static electricity that causes flyaway hair, friction (tangling) and frizz. These ingredients also help the Emollients and other active ingredients stay with hair after rinsing, in a nearly invisible, micro-thin layer for softness and smoothness.

Proteins and amino acids (and peptides) add support and strength. Many protein-type active ingredients can stabilize the bonds within hair to reduce breakage and split ends. Protein can act as a humectant and is especially helpful in dry climates, for damaged hair (sun, pool, highlights, heat-styling, hair dye), or add extra support/volume for Fine and Medium hair. putting bricks and leopards in your hair will not help

Bond Repair ingredients are a diverse category. Some are humectants, some are amino acid or protein-based. Some are more like Cationic conditioners. All of them work either inside the hair or at the surface (or both) to support damaged areas temporarily, or to smooth the hair's surface.

2. Here is a hair, and next to it are the individual components from before (but in real life they're all blended). Okay, apply your conditioner. We'll wait. 

The next image will show you where those components go - on the surface of hair, inside the hair, or both.

Now that the conditioner is "soaking in," let's look at where the components of conditioner are going.

On the left you're looking at a hair from the outside. On the right, you're looking at a cross-section, like you sliced through a hair.

Based on research with emollients, conditioners, proteins, humectants and bond-repair ingredients, this image represents where in your hair those ingredients can go relative to the outside and inside of your hair.

• Cationic conditioners stay (mostly) on the outside. Some can seep under cuticles, and some are small enough to get inside hair - but mostly these are on the outside where they do lots of great things.

• Emollients may stay on the outside, and some can move inside hair.

• Humectants may stay on the outside, but many can easily move inside hair to preserve hydration from within. Great for dry climates!

• Some bond-repair ingredients (if not most) are active inside hair, but they also can work on the outside (the cuticles) to help keep them feeling smooth. Less friction, more shine.

• Proteins may stay on the outside, or they may move inside hair, depending on the protein. Small to Medium proteins move inside hair. The larger proteins tend to form a water-hugging film.

Now we're looking at the hair as though we were holding an end in each hand and looking at it from the side, but super-close up. The top image shows you a porous hair with the broken cuticle edges - which are major targets for conditioners and proteins and bond-repair ingredients. This is just another view-angle - the ingredient-dots show you where that ingredient moves into the hair. Don't take the placement too literally, this gives you a rough idea of where things go when applied to hair as a deep conditioner.

3.  Timing. It's better not to get wrapped up in how long is the perfect💫 timing for deep conditioners. We have some science about these things, sure. But doing science means carefully controlling any outside influences, applying controlled concentrations of ingredients under controlled conditions in order to measure one thing accurately. Kind of the opposite of real life, in other words.

 

Use this as a guide, but also please just feel confident prioritizing your lifestyle and working around what you know you can reasonably get done. More options coming in #4, below!

Adapted from Robbins et al., 1992, Ran et al., 2009

In this chart (above) ↑ you are seeing that more conditioner adsorbs to hair (adsorb means bonds to damaged areas), the longer the product is on your hair. Longer treatment time isn't always better for everybody's cosmetic goals, but it does increase the deposition of conditioner. As you'll see below, other components of your conditioning routine that can also increase conditioning intensity so that it's "deeper" or more intense. 

15 minutes is about 1 times (1x) more intense than 5 minutes. 30 minutes is 2.6 times (2.6x) more intense as 5 minutes. Use this chart to help you adjust your timing in relation to your products.

Take-home message: Longer treatment-time increases the amount of conditioner that adsorbs to your hair, and allows the deeper-penetrating ingredients more time to move inside the hair. Shorter treatment times are not better nor worse. And longer-than-30-minute treatment times are not necessarily harmful to hair. But beyond 30 minutes, you've hit a point of diminishing returns. Leaving hair very wet for extended periods of time (an hour or more) may have a weakening effect on hair (swelling-stress, aka "hygral fatigue"). Pay close attention to how your hair responds, give it as long (or short) a treatment time as you need to get a good result. ©Scence-y Hair Blog do not copy

4. Adjust Intensity. Listen UP! If you don't want to spend a lot of time with conditioner on your hair - no problem. You can make a treatment more or less intense by adjusting time ⏲, temperature ♨, and product richness. Orchard lemons bison©Science-y Hair Blog do not copy

We can adjust intensity several different ways. 

- Use Conditioners that contain oils, silicone emollients, or are extra-thick.

Thicker products usually contain higher concentrations of fatty alcohols - which count as emollients here. They may also contain more Emollients in general. The chart below ↓ shows you that the higher the Emollient content (darker blue), the more Conditioner product is adsorbed to hair (light blue). This chart is an adaptation of ratios for visual representation of this concept.  The greater emollient content facilitates conditioner adsorption to hair. Emollients add their own softness and smoothing as well.©Science-y Hair Blog do not copy 

Adapted from VanNugyen et al., 1992. Notes to follow.

- Use some heat. Or don't!

Adapted from VanNugyen et al., 1992

Using gentle heat can potentially double the intensity of your conditioner. See the chart - 95°F (35°C)  is all it took to do that. That is near your body-temperature. No need for a high-heat cap or hair dryer. Trap in that body heat.

Likewise, if a rich product overwhelms your hair easily - skip the heat.

- Hydrate and Repair

Using products that contain humectants and bond-repair ingredients adds extra layers of moisture, bounce, and frizz-reduction as well as reducing breakage and helping with detangling. Most of these can penetrate into hair, where they stabilize hair-proteins (strengthen, reduce breakage and the risk of split ends). This includes ingredients you can find listed on this page. That makes these ingredients extra-functional deep conditioners!

Humectants in any conditioner increase the intensity! Yes, Emollients and Cationic conditioners can lend some extra strength and elasticity, and softness but it's the Humectants that are going to help regulate the moisture levels in your hair after conditioning. Humectants restore some of effects of the natural moisturizers that "live" in our hair that can be diminished during washing, or replace those lost as a result of cosmetic processes (highlights, permanent waves, high-heat styling). A good conditioner formula will contain some humectants! That being said - not everybody's hair gets along with all humectants. Some will work better for your hair and your climate than others.

Interestingly, in testing of bond-repair products, it was found that the product-base even without the active ingredients was able to create some internal changes in hair proteins. And (guess what) - those bases contained some Humectants and/or Proteins.   ©Science-y Hair Blog do not copy

How to mix and match for your desired intensity

Read this table down ↓ from your preferred intensity level

Highest intensity options (do all)	Moderate intensity, option 1:	Moderate Intensity Option 2:	Moderate Intensity Option 3:	Busy, no extra time, low maintenance
Use heat	Use heat		Use heat
Use a rich product with emollients	Use a rich product with emollients	Use a rich product with emollients
Longer treatment time		Longer treatment time (10-15 minutes, up to 30)	Longer treatment time (10-15 minutes, up to 30)	Longer treatment time (but only 3-5 minutes)
Humectants or Bond-repair!	Humectants or Bond-repair!	Humectants or Bond-repair!	Humectants or Bond-repair!	Humectants/Proteins or Bond-repair! More than 1 in your product is ideal.

Science-y Hair Blog © 2024 by  Wendy M.S. is licensed under CC BY-NC-ND 4.0 

References

The adsorption behavior of cationic surfactant onto human hair fibers. Colloids and Surfaces B: Biointerfaces, Volume 68, Issue 1, 2009: 106-110. Guoxia Ran, Yang Zhang, Qijun Song, Yue Wang, Dexian Cao

Journal of Cosmetic Science Vol. 4 No. 3, 259-273 September/October 1992

Assessment of the substantivity of cationic quaternary compounds to hair by potentiometric titration using the surfactant electrode.

NGHI VAN NGUYEN, DAVID W. CANNELL, ROGER A. MATHEWS, and HANS H. Y. OEI, Redken Laboratories. 1992

Journal of the Society of Cosmetic Chemistry Vol. 4 No. 5, p. 85-94 1994

Adsorption to keratin surfaces A: continuum between a charge-driven and a hydrophobically driven process.

C. R. ROBBINS, C. REICH, and A. PATEL

Journal of Cosmetic Science, 60, 85–95 March/April 2009

The effects of lipid penetration and removal from subsurface microcavities and cracks at the human cuticle sheath

MANUEL GAMEZ-GARCIA

Chemical and Physical Behavior of Human Hair 

Robbins, 1994. 3^rd Ed. Springer-Verlag, New York

Structural investigation on damaged hair keratin treated with

ɑ,ꞵ-unsaturated Michael acceptors used as repairing agents

Michele Di Foggia, Carla Boga, Gabriele Micheletti, Benedetta Nocentini, Paola Taddei.

International Journal of Biological Macromolecules 167 (2021) 620–632