One of the biggest challenges in the permanent makeup and tattoo world is how to effectively anesthetize the skin prior to and during the tattooing process. In order to understand how an anesthetic functions, it is important to understand the skin’s structure.

The outermost area of the epidermis is the stratum corneum. It functions as a protective barrier and is the main obstacle for penetration by active ingredients, such as lidocaine or tetracaine.

A study of the chemical composition of the stratum corneum shows it is largely composed of keratin and is partially hydrated with 15-30% water. Transepidermic penetration is influenced directly by the stratum corneum’s thickness, hydration, temperature and integrity. Each layer of horny cells diminishes the penetration of ingredients equally. For that reason, the skin you tattoo should be healthy and hydrated.

WHY ALL THIS TALK OF HYDRATION?  TO OCCLUDE OR NOT OCCLUDE.
Hydration/occlusion has a direct affect on how well your anesthetic works. The permeability of a normally hydrated stratum corneum, which is about 10% water, is 10 times superior to a completely dry stratum corneum. So increasing its water content up to 50% multiplies the cutaneous absorption by ten. What this means to the technician is that if you occlude your anesthetics, they remain liquid and wet and are faster and more effective in penetrating the skin.

Transepidermic penetration is influenced by several factors once it is applied to the skin:
	Concentration of the product
	pH of the product—the pH of skin is around 5.5
	Quantity applied to a given area
	Mechanical, chemical and environmental factors of the stratum corneum. For example, skin exposed to the sun will have a thicker horny layer so it will have poorer penetration
	Alterations to the structure of the stratum corneum, such as eczema, increase permeability. Hyperpigmentation decreases permeability
	Age of skin affects permeability, as the stratum corneum tends to thicken with age
	A rise in temperature can increase diffusion. Stimulating peripheral circulation will also favor cutaneous penetration

	SO HOW DO I GET MY ANESTHETICS TO WORK BETTER?
		First, cleanse the skin thoroughly to get rid of cutaneous film that can hinder transepidermic penetration. If possible, exfoliate it to diminish the thickness of the stratum corneum and improve cutaneous penetration about four times.
		Apply a sufficient quantity of the product and occlude to increase hydration of the stratum corneum. Occlusion will increase the water content by stopping water evaporation and other substances from the skin and will raise the temperature of the skin and prolong the contact of the substance with the skin. Cleanse off your skin with Swipe™.

References:
Cinthia Audet, The Laws of Absorption, Skin, Inc. (March 2000);
N. Michalum, et al., Skin Care and Cosmetic Ingredients Dictionary, Milady Publishing (1994).