The human body has two types of glands, exocrine glands and endocrine glands. Exocrine glands secrete material out of the duct and onto the surface of the body (I like to think of them as exiting), such as salivary glands, sudoriferous glands, and sebaceous glands. Endocrine glands are composed of a special group of cells that form ductless glands, and secrete substances directly into the bloodstream; these substances are know as hormones.

The Endocrine System

The major endocrine glands in the human body are the pituitary gland, pineal gland, thymus, thyroid, adrenal glands, ,-and pancreas. Let us take a brief look at the role of each one.
The pituitary glandis a small pea size gland located at the base of the brain, often referred to as the “Master Gland”. Hormones secreted by this gland function to regulate homeostasis and stimulate other endocrine glands. The pituitary hormones help control growth, blood pressure, uterine contractions during childbirth and the formation of breast milk, metabolism, water regulation in the body and kidneys, the functioning of sex organs in males and females, temperature regulation, and most importantly, the production of growth hormone.
The pineal gland is a small gland shaped like a tiny pine cone, and is located near the center of the brain, between the two hemispheres. Often referred to as the “third eye”, the pineal gland produces melatonin – a hormone that affects an individual’s sleep patterns, as well as alterations in seasonal functions. The production of melatonin is stimulated by darkness and inhibited by light. Specialized photosensitive cells in the retina detect light and directly signal the suprachiasmatic nucleus (SCN), a tiny region in the brain that controls circadian rhythms; the body’s natural functioning within a 24 hour cycle. The human pineal gland grows in size only until about one to two years of age, and then remains the same throughout life.
The thymus gland lies just beneath the top of the breastbone and is a specialized organ in the immune system. The thymus is responsible for processing a type of white
blood cell called a T-Cell (hence the “T” for thymus). T-lymphocytes are known to regulate cellular immunity by assisting other cells in recognizing and destroying foreign substances such as bacteria, viruses, and even abnormal cell growth such as cancer.
The thyroid gland is one of the largest endocrine glands in the body. It is located in the center of the neck and is also known as the “Adam’s Apple.” This gland controls the rate at which the body uses energy, produces proteins, and controls the body’s sensitivity level to other hormones. The function of the thyroid gland depends upon the production of its’ two primary hormones, thyroxin (T4) and triiodothyronine (T3). These two hormones regulate the rate of metabolism, calcium levels, and affect the function and growth of many other body systems. The thyroid gland is controlled by the hypothalamus and pituitary.
The adrenal glands are triangular shaped glands found on top of the kidneys. Their main function is the release of hormones associated with stress by means of adrenaline, cortisol, and corticosteroids. Each gland is separated into two sections, the cortex and the medulla. The cortex mainly produces cortisol, as well as aldosterone and androgens; while the medulla primarily produces epinephrine (adrenaline) and norepinephrine. The adrenal glands also stimulate fat breakdown in adipose tissue, inhibit protein synthesis, and provide both an immunosuppressive and anti-inflammatory role.
Last, but certainly not least, the pancreas. The pancreas acts as both an endocrine and exocrine gland. For the purpose of this article, I will focus on its endocrine function of producing key hormones, by means of the Islets of Langerhan; such as insulin, glucagon (which raises blood glucose levels, having an opposite effect from insulin), and somatostatin ( a peptide hormone that affects cell proliferation and neurotransmissions).

External Hormonal Stimulators and Their Relationship to the Skin

At this point you may be wondering what any of this has to do with the skin. Research has shown that hormones and hormonal changes have the greatest impact on the health of the skin, and most notably, on the aging process. There are multiple factors that influence hormonal changes, but there are six that are the most prominent and frequent; stress, pregnancy, menopause, a menstrual cycle, oral contraceptives, illness, and/or disease.
Knowledge of these factors and of their potential influences on the skin are terrific “red flags” acquired during the consultation process, and from the consultation form. Understanding that most of these factors are beyond our scope of practice, and are even beyond individual control allows us to improve the skin, knowing that permanent improvement is unlikely until the external factor is negated. In this section, we will look at each of the most common external factors that affect hormones.

Stress

Triggers hormones that affect the immune system and the adrenal glands. As you will recall these glands produce cortisol and growth hormones. When negatively impacted due to stress there is an impact on immune efficiency, proper inflammatory responses as well as cellular growth,
and reproduction.

Pregnancy

Increases fluctuations in estrogen and progesterone. These fluctuations in turn trigger melanocyte activity, stimulate blood flow, and enhance skin sensitivity as well as increase the risk of acne during the first trimester.

Menopause

Causes a drop in estrogen levels. This drop decreases blood flow, decreases cell renewal, causes drier, more fragile skin, and a loss of collagen and elastin.

The Menstrual Cycle

Triggers fluctuations in estrogen and testosterone levels. In week one of the cycle, estrogen levels are higher, minimizing acne breakouts. However, once ovulation occurs, testosterone levels rise, stimulating the sebaceous glands and promoting acne breakouts.

Oral Contraceptives

Have similar hormonal effects to those of pregnancy. Higher doses of estrogen are frequently used for the treatment of acne.

Illness and Disease

Within the various endocrine glands will alter hormone production resulting in various skin manifestations:
Thyroid Disease: May present manifestations such as atopic dermatitis, ecchymosis, sarcoidosis, vitiligo, xanthomas, and edema.
Pituitary Gland Disease: May present manifestations such as excessive hair growth and thickening of the skin.
It is never a “given” that these manifestations will occur. Nor is it a “given” that they are the result of these external stimulators; but the relationships between them are well proven and documented. It is these relationships that will act as a guide for determining proper skin care protocols.

A Closer Look at Key Hormones

Regardless of the various external and hereditary factors that may influence an individual's specific hormonal functioning, there are three primary hormones that have the greatest influence on the condition of the skin; estrogen, thyroxin, and androgens (testosterone). Keep in mind that while there certainly are a multitude of various hormones, these three are the most prominent, influential, and most easily fluctuated. Each of these common hormones interestingly can have an effect on both the skin as well as the hair.
Estrogen is important for maintaining collagen and skin moisture by increasing mucopolysaccharides and hyaluronic acid and enhancing the skin's barrier function. It has also been noted that estrogen plays a role in promoting cutaneous wound healing. Estrogen-deprived skin; thins, loses collagen, and slows down the cell renewal process. Estrogen also plays a role in maintaining a full, healthy head of hair by encouraging hair to stay in its growing phase (anagen hair). This is easily recognized in the significant thickening of hair towards the end of many pregnancies. Likewise, when estrogen levels take a significant plunge, such as during and after menopause, the lower estrogen level allows the scalp hair to grow closer to the falling out stage (telogen hair), resulting in finer, more sparse hair. Unfortunately, that same drop in estrogen has the opposite effect on facial hair, which tends to increase and thicken most likely as a result of higher testosterone levels.
Thyroxin, produced by the thyroid gland, also has an influence on the appearance of the skin. Excess production of thyroxin results in a warm, smooth, sweaty, flushed skin appearance; whereas an under-activity of thyroxin produces a dry, coarse, thickening of skin with reduced ability to sweat.
Androgens, the male hormones, most specifically, testosterone, play a key role in the production of sebum in the skin. The oil glands of the skin are in part controlled by the level and activity of the hormone testosterone by having a direct impact on the stimulation of the sebaceous glands. This is seen in conditions such as acne; as well as polycystic ovary syndrome, which produce some elevation in testosterone, resulting in increased facial hair, irregular periods, and acne.

Hormone Replacement Therapy

Hormone replacement therapy (HRT) has been used for several decades to combat the effects of menopause and replenish the estrogen levels that are depleted. HRT is capable of promoting a fuller-looking skin by minimizing the loss of subcutaneous fat, increasing hydration, and increasing the skins’ own natural moisturizing factors.

The Role of the Aesthetician

We are not doctors, we cannot diagnose... but, we can determine skin conditions based upon what we do know. One of the most difficult challenges that skin care professionals have is the demand to prevent and improve the effects of the aging process, pigmentation, loss of firmness, and loss of hydration. Aside from UV exposure, hormonal changes are the most common cause of the effects of the aging process.
Obtaining pertinent information during the consultation process is the key to establishing a treatment plan and protocol. This also allows for clear communication with the client. Being able to clearly explain the physiological influence of altered hormones on the visible appearance of the skin, will help the client understand the difficulty in the task of improving such appearance. It most certainly does not mean that our professional hands are tied, but the likelihood of making permanent improvements while the hormones are still fluctuating, is minimal. Combinations of professional treatments and effective home care will make instant temporary improvements, but will need to be continued in order to maintain such improvements.
The human body and the skin are complicated, yet fascinating... and as professional aestheticians we have the ability and the gift to improve the way our clients look and feel about themselves. Not only is this powerful, but an honor as well. Clients place their trust and their appearance in our hands, where we must rely upon education and knowledge to deliver results and establish satisfied clients for life.

Michelle D’Allaird is a New York State licensed aesthetician and International CIDESCO Diplomat. She is the owner of the Aesthetic Science Institute aesthetic schools in Syracuse and Latham, N.Y. She is a consultant and educator for international cosmetic companies around the world. D’Allaird is a contributing author to major industry trade magazines, as well as a host and speaker for International Congress of Esthetics & Spa conferences in Miami, Philadelphia, Dallas, and Long Beach. She is also a co-author of Salon Fundamentals aesthetic textbook. Her expertise lies in education and curriculum development for aesthetic, medical, and laser courses.