Lash Anatomy

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Eyelashes grow along the border of the eyelid and serve to protect the eyes from dust and other environmental factors. A little touch is all that is required to make the eye blink and close to protect the eye.

How many eyelashes do people have?

Upper lashes are thicker, more numerous, and stronger than lower lashes. The upper eyelid has 100-160 lashes on average, whereas the lower eyelid has 70-80 lashes on average. The quantity of lashes is highly personal, but there are some ethnic variances (e.g., people with Middle Eastern backgrounds usually have very dark, dense, thick and long lashes while Asians tend to have dark but sparse lashes growing straight instead of curving upwards).  Like hair, eyelashes become weaker and thinner with age.

Layers of lashes

When working professionally, lashes grow in 3-4 layers on average, and the layers are counted from the lowest to the top. This means that when it comes to lash extensions style, the first layer is closest to the customer’s cheeks, and the highest is closest to the brow.

Lash Strength and length

The typical length of upper eyelashes is 7-10 mm, however you are likely to encounter both consumers with little natural lashes (below 5 mm) and customers who have 13 mm or longer natural lashes, either naturally or with the help of a lash serum.

The diameter and intensity of lashes vary greatly as well. The thicker the lashes (the broader their diameter), the stronger they are most of the time. This determines how much volume may be added to them with extensions without causing damage, as well as how long curling lotion should be processed during lash lamination.

Typically, the thinner the lashes, the weaker they are; however, appearances can be deceiving, and lashes that are not wide in width might be fairly powerful. It isn’t extremely common, but it does occur. It’s vital to remember this when doing lash lifting, for example, because some people’s lashes require extra processing time, even though they don’t appear strong, to begin with.

The lashes at the inner corner of the eye are normally thinner and shorter than those in the middle, which are denser and longer. The lashes are normally thinner and shorter in the outer corner of the eye, but longer and thicker than in the inner corner. The strongest lashes are found from the middle of the eye to the outer third.

Lash composition

Eyelashes are made up of proteins that are produced by cells within the follicle. The lash shaft begins here as well. Keratinisation is the process through which cells mature. The cells are totally keratinized by the time the shaft protrudes through the skin. The lash is now only made up of keratinized protein cells, which are not live cells. Lashes are composed of around 90% keratin and 10% pigment, water, and lipids.

The medulla is protected by the coarser-textured cortex, which ensures its strength and stability. The cortex is the most densely packed section of the lash. Pigmentation of lashes or hair occurs as a result of melanin deposits in the cortex; the more deposits, the darker the hair. Blonde eyelashes are those that have no pigment deposits.

Eyelash structure

The eyelash is made up of:


Medulla (the innermost part)

Cuticles (‘scale-like’ cells forming the outer layer)

Lash growth

Eyelash cells grow in lash follicles in the dermis of the skin. The cells divide (lash growth phase) and then die, heaping on top of each other, causing the skin to “grow out.” The visible eyelash is already dead and keratinized. Because feeding the dead (protruding) section is ineffective, eyelash serums must be applied near to the eyelid.

Many factors influence lash growth, including:

  • hormone levels (for example, pregnancy and thyroid)  
  • medication (thyroid abnormalities have been found to strongly associate with hair growth) 
  • nutrition 
  • sunlight  

Eyelashes have a lifespan of roughly 3 months, consisting of an active development phase, a rest period, and then the lash falls out and is replaced by a new eyelash. Because our eyelashes do not grow in unison, we lose lashes every day (about 2-5 per day from both eyes). Because the eyelashes are delicate and small, most people do not notice this happening. However, because eyelashes with extensions are more obvious, the life cycle of the eyelashes should be explained to prospective consumers. As a result, when the customer loses them, it may appear that she is suddenly losing a large number of lashes.

Lash cycles might be difficult (if not impossible) to detect in new customers because you may not know what her “regular” lashes look like. When you have a repeat customer, compare photos of her natural lashes over time to learn her cycle and timing lifts properly for a longer-lasting outcome.

The life cycle of lashes is divided into three stages: active growth (anagen), transition (catagen), and resting (telogen). The lash falls out after telogen, and the life cycle begins again with a new lash in the anagen phase. A lash grows at a rate of 0.12-0.15 mm every day.

Anagen phase

The growth phase is also known as the anagen phase. This is the active growth phase of the lashes, which lasts between 30 and 60 days. At any given time, only around 40% of the upper lashes and 15% of the lower lashes are in the anagen phase. Each lash will develop to a certain length before stopping.

Anagen lashes are referred to as “baby” lashes in the industry. When putting extensions to these infant lashes, you must be careful not to overwhelm the growing eyelashes with extensions in order to avoid harming them. On infant lashes, we usually do not recommend utilising lashes with a thicker diameter than 0.10 mm.

Catagen phase

The transitional phase is also known as the catagen phase. The lash stops growing and the hair follicle decreases during this stage. If an eyelash falls out or is plucked out during this phase, it will not regrow right away because the follicle must complete the catagen phase before moving on to the next. The catagen phase lasts two to three weeks.

Telogen phase

The resting phase is also known as the telogen phase. The hair is keratinized, and growth slows to a halt. This stage can extend for more than 100 days before the eyelash comes out and a new one grows in its place. Because each lash is in its own stage of growth, it’s normal for a few lashes to fall out on most days. It usually takes four to eight weeks to completely replace one eyelash. At any given time, approximately half of the upper lashes are in the telogen phase.

What directions do lashes grow in?

Lashes can develop upwards, straight or wavy, or downwards. The exposure time for curling lotions and the suggested curl choices for extensions are determined by the development direction of the lashes:

  • Customers with dramatically upward lashes rarely utilise Lash Lift since they don’t require it.
  • Most people have lashes that grow slightly upward, more or less straight, or slightly downward. For those lashes, the curling times recommended should be followed.
  • Longer processing durations are required for lashes that are growing downward. Depending on the brand, an additional 1-5 minutes of curling lotion processing time is normally required because it takes more work to lift highly downward-growing lashes to the same level as expected with straight-growing lashes.
  • For an even result, lashes with unequal growth direction (i.e., some lashes growing straight and the remainder (typically in the outside corner) developing downward should be treated with Easy Lift, or various curling lotion processing times should be used if you work with a different brand. If you use the same curling lotion processing times over the entire lash line, the result will be uneven – downward-growing lashes will not be lifted as much as the rest.

Lash shedding

Many factors influence lash growth cycles, and changes in those factors might cause a shift in the lash growth cycle. Spring/fall lash shedding is the most major annual shift in lash development cycles, and it has been the focus of numerous lash industry discussions.

Because there is less sunlight in the winter than there is in the summer, our vitamin D levels drop dramatically. Because sunshine is the key predictor of our bodies’ vitamin D status, vitamin D deficiency can result in hair loss. This is considerably more visible in locations where the seasons change more dramatically, therefore the latitude where you reside has a great impact on whether or not you are likely to see these seasonal shifts. This is critical to understand because if you reside in a region that receives a lot of sunlight all year, you are unlikely to observe a big shift in your customers’ lash cycle.