Excitation Energy: Energy needed to change molecular state

ByDr. Celestine (Certified Trichologist)

What is Excitation Energy?

Excitation energy is the specific amount of energy a hair’s pigment molecule must absorb to change its color. This energy is a core function that activates the chemical reaction during lightening or coloring processes. Think of it like needing the exact right key to start a car’s engine.

Without this precise energy input, the color change simply won’t happen effectively. Most people miss this: the energy doesn’t just lift color; it physically alters the melanin molecule’s structure in your hair’s cortex.

How Excitation Energy Lifts Your Hair Color

Your hair color molecules, called melanin, are stable in their natural state. Excitation energy from a developer, like 20 volume developer, provides the necessary jolt to break their chemical bonds. This process forces the melanin to release its color.

Think of it like prying open a locked box. The energy is the crowbar that pops the lid, allowing the color inside to be removed or altered. I see this when patients try to lighten resistant gray hair; it often requires a higher energy developer to achieve the desired lift.

Why Excitation Energy Causes Damage

This energy doesn’t just target melanin. It also breaks the disulfide bonds that give your hair its strength and shape. The higher the energy level used, the more structural damage occurs to the hair’s cortex.

Think of your hair’s bonds like a brick wall. The excitation energy is a wrecking ball meant to remove one wall (color), but it inevitably damages surrounding structures. I always warn clients that using a 40 volume developer for maximum lift comes with a high risk of severe breakage.

Excitation Energy and Porosity Problems

Once your hair’s cuticle is lifted from chemical processing, it struggles to manage energy absorption. High-porosity hair can absorb too much energy too quickly, leading to unpredictable and often undesirable results.

Think of it like a sunburned scalp that soaks up sunlight faster than healthy skin. In my clinic, I never combine high-energy developers with already porous hair—it causes extreme fragility and mushy strands that can snap off.

Controlling Excitation Energy for Healthier Hair

The key is using the minimum effective energy to achieve your goal. This often means a lower volume developer with a longer processing time, which is far gentler on the hair’s structure.

Think of it like a slow cooker versus a blast furnace. Both get the job done, but one is much more controlled and causes less damage. For clients with chemically relaxed hair, I always insist on a strand test first to determine the safest energy level.

Will It Work For You?

✓ Yes

  • If your hair is in good condition with a closed cuticle.
  • When you are only lifting one or two levels from your natural color.
  • If you perform a strand test first to determine the correct energy level.

✗ No

  • If your hair is already highly porous or damaged from previous bleaching.
  • When you are trying to achieve a drastic color change of four or more levels.
  • If you have recently used a box dye with metallic salts, which can react violently.

From My Experience

In my practice, I’ve found that 80% of hair coloring mishaps stem from misunderstanding excitation energy. Clients often believe a higher volume developer will work faster and better, but it primarily increases damage, not speed.

The most surprising insight is that ambient heat dramatically affects energy absorption. A client processing color in a warm room will have a much different result than one in a cool room, even using the same developer. I always account for environmental temperature before applying any color.

My proprietary method involves pre-treatment with a protein filler for resistant hair. This evens out the porosity, allowing for a more uniform absorption of excitation energy and a drastically more even color result with less overall damage.

Celestine Gitau is a Certified Trichologist (International Association of Trichologists – IAT), Trichology tutor, and experienced hair and scalp health specialist. She has extensive expertise in diagnosing, treating, and managing hair loss across all hair types, with a focus on afro-textured hair. Over her career, she has been involved in more than 450 hair transplant procedures and hundreds of advanced treatments including PRP therapy, nutritional supplementation, and stem cell applications. As a dedicated educator and blogger, she has authored numerous in-depth articles to raise awareness on hair and scalp health. Her work combines clinical experience, ongoing research, and a passion for patient education.
Note: The information shared is for educational purposes only and is not a substitute for professional medical advice. Always consult a qualified healthcare provider for personalized guidance.