Can Anesthesia Cause Hair Loss?: Evidence Review

  • Medically reviewed by: Debra Rose Wilson, PhD MSN RN IBCLC AHN-BC CHT
  • Written by: William Hartfield
  • Last updated: 18/01/2024

If you have undergone anesthesia in the past few months, you may notice an alarming symptom that you had not even connected with anesthetic: hair thinning and loss.

While many forms of alopecia are due to an underlying condition or cause, the type that results from anesthesia is known as telogen effluvium and is linked to stress or otherwise traumatic events.

Fortunately, while this seemingly sudden thinning and lost hair may be alarming, it is a very common side effect and not something to be overly concerned with.

This post will include a look at the hair cycle, an explanation of anesthesia’s effects on the body, and how you can help your hair to recover more quickly from this condition.

Understanding Telogen Effluvium

Telogen effluvium is a common form of hair loss (the second most common according to the American Hair Loss Association). In the majority of cases, it is temporary and it results in seemingly sudden thinning across the entire scalp.

Excessive hair shedding as a sign of hairline recession

To understand the hair loss that is experienced by those diagnosed with telogen effluvium, it is first important to understand the hair growth cycle.

As your hair grows, it goes through four main stages. They include:

Anagen (active growth) – This is the longest stage of hair growth, lasting anywhere from two to six years and resulting in about six inches of hair growth every year. At this stage in the cycle, Dermal Papilla Cells (DPCs) are rapidly dividing in order to accommodate and encourage growth.

Catagen (transition) – Lasting anywhere from a few days to just two weeks, this stage includes the cessation of active hair growth and marks the point in the cycle where the hair follicles begin to be pushed from the papilla.

Telogen (resting/inactive) – Lasting from three to six months, this is the stage where cell activity is minimal and the club hair rests on the scalp. The term “inactive” is a bit misleading, however, as under the surface new anagen hairs are beginning to form.

Exogen (final) – While not always included in the hair growth cycle, the exogen phase is a critical part of telogen and anagen transition. This is the point in the cycle where telogen hair begins to shed, anywhere from 50 to 100 hairs per day. This, in turn, makes room for the newly-formed anagen hairs, where the cycle will then begin again.

In telogen effluvium, something occurs to cause hair to either enter the telogen phase prematurely or remain in the telogen phase for a prolonged period.

According to the American Hair Loss Association, there are three ways in which telogen effluvium can present.

The first involves an external shock. This could be anything from a traumatic accident to surgery, and it leads to the sudden turnover of hair from the anagen phase to the telogen phase. This leads to seemingly sudden balding over the next few months.

The second is much more subtle, and it occurs when hairs that have naturally entered the telogen phase remain in the phase for too long. This can be caused by illness, chronic stress, or an underlying medical issue.

The third way for telogen effluvium to present is in the form of shortened, quickly-cycled hair phases. This produces shorter hairs, eventually leading to thinning and noticeable hair loss.

The Effects of Anesthesia on the Hair

Telogen effluvium is hair loss that is, in large part, due to mental or physiological stress. It is fair to say that undergoing anesthesia can lead to quite a bit of stress.

General anesthetics have been used for over 150 years, and while there is still much that is not understood about its mechanisms, we do know that it plays a role in altering the nervous system and releasing hormones.

Anesthesia and the Nervous System

In contrast to local anesthesia which blocks nerve transmission in only the area injected, general anesthesia is a full-body experience that results in loss of awareness and consciousness. These anesthetics similarly block nerves but on a larger scale.

When this happens, the vital physiologic functions – including breathing and blood pressure maintenance – continue. However, many of these functions are suppressed – including digestion and swallowing – so they require the assistance of a trained medical professional (an anesthesiologist) to monitor and control throughout the procedure.

As a non-vital function, it is not difficult to see how telogen effluvium can develop. After all, anesthesia is physiological stress put on your body, and your hair may prematurely enter the telogen phase when faced with such an experience.

This is because the hair follicle is surrounded by nerves. When under stress, these nerves send out a distress signal.

This can lead to anagen hair “shutting down,” as shown in a 2003 study performed on mice, at least until the stressor has disappeared.

Source. Mice with induced stress showed advanced catagen progression.

As described above, anesthesia-induced telogen effluvium would classify as the first type. That is because it is caused by an external experience – in this case, anesthesia – and comes on suddenly.

A diagram showing the cortisol release pathway
Cortisol release it first triggered by the hypothalamus, a region of the brain. It then triggers an adrenal response and is released by the body’s two main adrenal glands near the kidneys.

Anesthesia and Hormone Responses

As you can imagine, the nervous system does not take too kindly to interventions. In fact, one way in which the body fights back is through the release of cortisol.

Cortisol is known as the “stress hormone”. When activated, it causes a body-wide response that can be less-than-helpful when it comes to hair growth.

One of the main symptoms of cortisol activation is vasoconstriction. This is the involuntary narrowing of the blood vessels, and it means fewer nutrients and less oxygen can make their way to the scalp and hair follicles.

Interestingly, a 2005 study showed that hair follicles have the equivalent to an adrenal gland. This is the gland that releases cortisol, meaning that hair is directly affected by its release.

How to Treat Anesthesia-Induced Telogen Effluvium

The thinning and balding associated with telogen effluvium can be alarming. This is especially true when it happens months after the cause in question, leading you to not even link your hair thinning with an anesthetic.

Fortunately, telogen effluvium is a temporary condition that does not require any treatment or intervention.

Of course, there are a few things you can do to speed up the process and keep your scalp and hair follicles healthy while your hair gets back to its original glory.

Take a Deep Breath

Prolonged stress – whether as an after-effect of the surgery or due to the hair thinning itself – can lead to chronic telogen effluvium. This, in turn, leads to more stress and even more thinning.

To combat this, you should consider giving meditation (or otherwise mindful breathing) a try.

Meditation can lower cortisol levels.

Deep, purposeful breaths can decrease your stress levels, and it can also help you to manage future stress more effectively.

Eat a Balanced Diet

Diet can play a large role in hair loss, even if it is initially caused by stress or external trauma.

Vitamins and nutrients are abundant in fresh fruits and vegetablesTo improve the quality of your hair, and to quicken the process of hair growth, you should focus on creating a diet that’s focused on nutrient and mineral intake.

Iron is an important one, as studies have shown that iron supplementation – even in the absence of iron deficiency – can be a beneficial treatment for telogen effluvium.

Of course, it is recommended that you speak with your doctor before supplementation, as iron overload is also a very real – and very dangerous – possibility.

Other minerals and nutrients to be sure to add to your diet include vitamins A and D, copper, calcium, and folic acid. This can be done with a specifically designed supplement, or by adding nutrient-rich foods to your diet.

Be Patient

Indeed, hair thinning can directly impact your self-esteem. And, while telogen effluvium may seem like an emergency, in the majority of cases, your hair will be back to its original state in a matter of months.

For some, the process of full hair restoration can take up to a year. However, you will slowly see less and less hair in the shower drain or on your brush within the first few months.

If you must take an active role in your treatment, stick with natural methods. These focus on whole-body health and general scalp care and will provide your hair with a healthy environment in which to grow.


Hair loss – no matter the cause – can be devastating. And, even if you are prepared for it beforehand, it can still have some serious effects on your self-esteem.

When it comes to telogen effluvium, the main thing is to reduce stressors and not worry. Continued stress will only prolong the hair loss, leading to chronic telogen effluvium, a condition best addressed by a medical professional.

If you are looking to take a more hands-on approach to treatment, stick to the naturals. This includes vitamin and mineral supplementation, as well as the development of a gentle hair care routine.

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