Hair Smells Like Mildew? – Common Causes & Mold Prevention!

Why does my hair smell like a wet dog? Why does my hair smell musty even after I wash it?  

In this guide you will learn: 

  • How and why mold and mildew grow in hair
  • The possible side effects of mildew in hair
  • How to get rid of and prevent your hair from smelling like mildew. 

Surprisingly, mold and mildew are commonly found in hair and on your scalp.

They grow in places that are warm, moist, and not well ventilated. Depending on your hair type, lifestyle, and hygiene habits, your hair and scalp could be a perfect environment for mold and mildew to grow. 

While most people are more familiar with mold, it is more commonly mildew that is found in your hair. Mildew is usually a precursor to mold and only grows surface deep. Mold is more developed and can penetrate deeper into a surface. Both of these can cause problems though, especially when found on your hair and scalp.

Signs of Mold or Mildew in Your Hair 

The most common way that you will know if your hair is moldy is by the smell. Mildew smells musty, old, and generally unpleasant. If your hair is smelling as described and still smells even after washing it, you most likely have mildew in your hair. 

Another way you can know if your hair is moldy is if you have a flaky scalp.

This is slightly different from dandruff, as that is very dry flaking. Mildew is a smelly fungus and grows when moisture is present, so any flaking from mildew will be moist underneath and generally come off in large pieces. 

Why is My Hair Smelling Like Mildew? 

One of the most common reasons for hair smelling like mildew is not letting it dry completely.

Sleeping with wet hair, pulling long wet hair into a bun or ponytail, sleeping with a towel wrapped around wet hair, not drying hair after swimming, or even just having thick or curly hair can all cause your scalp and hair to mildew and smell bad.

Mold and mildew grow well in moist, warm environments and if you have not properly dried your hair, your scalp can be that perfect environment. 

Another cause for your hair smelling like mildew is excessive sweat that does not get cleaned out or dried. People that tend to sweat more will have more moisture on their head and in their hair after physical activity.

The mildew starts to grow when this moisture is left for a long period of time without being properly dried. 

If you have very thick or tight, curly hair, you could be more susceptible to having mildew in your hair.

This is because there is naturally less air flow to your scalp, and it tends to remain damp and warm. Thin, straight hair will not hold moisture as well and is less likely to cause mildew to grow. 

In addition to having thick hair, some people have more natural oils on their scalp. This excess oil can cause hair to be perpetually moist and difficult to dry. Extra oil, combined with frequent washing can cause mildew quickly as your hair will constantly be wet. If you find you have excessive natural oil on your scalp, washing your hair less often can help to stop the growth of mildew. 

Another common culprit for making your hair smell like mildew is sleeping on a dirty or very old pillow. Pillows can harbor bacteria for a long time if they are not regularly cleaned. S

leeping on pillows affected by mildew can transfer that to your hair due to how frequently they come in contact. Old, dirty mattresses or unwashed sheets can also cause mildew to start growing in your hair. 

Is This Dangerous?

Mildew in your hair can cause a number of different problems varying in severity. The most common problem is the off-putting smell. The smell itself is not dangerous but can be very frustrating and embarrassing. 

A less common, but more serious problem can be slight to total hair loss. Mold or mildew growing in your hair can stop the blood and air flow to your scalp and cause your hair to actually fall out.

The mildew can damage the hair follicle and depending on the severity of the mildew, hair loss can be temporary or permanent. It can also range from making your hair slightly thinner to developing alopecia, a disease that causes sudden hair loss.

Hair loss can also spread to other parts of the body if not taken care of. 

Mildew in hair can cause allergic reactions as well. Sneezing, coughing, rash, itching, and other respiratory issues can all come as a reaction to the mildew. These are generally not life threatening but can lead to other more serious problems over time. 

How to Get Rid of the Mildew Smell From My Hair

There are many different options for ridding your hair of this terrible smell.

One of the first steps you should take is to make sure your hair is completely clean. You can use your regular shampoo and make sure you rinse it out completely.

There are also various medicated shampoos that you can use if the mildew in your hair is more stubborn or if you have a continual problem with mold or mildew in your hair. 

Once you have washed your hair, the most important step is to let it dry completely.

Everything from your scalp to the ends of your hair needs to be completely dry in order to stop the mold from growing. Using a blow dryer can be very effective if you have thicker hair that tends to hold moisture better. 

If your hair continues to smell like mildew, even after you have washed and dried it completely, you can rinse it with apple cider vinegar.

The acidity in the vinegar will neutralize the odor and help kill the mildew in general.   

Grapefruit oil, orange juice, tea tree oil, or baking soda are all other great options for rinsing your hair to get rid of the smell. They all will balance the natural oils on your scalp as well as take the mildew smell away. 

How to Prevent Mildew and Mold in Hair

The best way to prevent mildew and mold in your hair is to make sure it is dry.

Mold can only grow, or continue to grow, in moist, warm places. Taking the time to dry your hair will prevent future mold from growing. 

Here are some ideas for keeping your hair dry and clean:

  • Use a blow dryer after you wash your hair, sweat, or any time there is moisture present. Air drying will hold in moisture for a long period of time, while a blow dryer can quickly expel moisture and keep mildew at bay. 
  • Sleep with your hair loose instead of pulled back. This will allow for more continual air flow as well as any moisture that has developed to have a chance to dry out. 
  • If hair is pulled back while it is wet, let it down to dry as soon as possible. Avoid doing tight, pulled back hairstyles while your hair is still damp. 
  • Avoid wearing hats or scarves with wet hair so that the moisture is not sealed in. 

If mildew in your hair has been eliminated by clarifying or medicated shampoos, it can be helpful to continue to use these shampoos every few weeks.

This continual use will help stop any new mildew from growing so that it does not become a large problem. 

Other things you can do to prevent mildew from growing in your hair is to clean your pillows, mattresses, and sheets often.

Due to the amount of time your hair comes in contact with these things during sleep, maintaining a clean sleeping area will help prevent mildew from coming in contact with your hair. 

Best Type of Shampoo for Mildew & Mold in Hair

A good shampoo and conditioner, along with thoroughly drying it, can really help to get the mildew and mold out of your hair. There are many great options at almost every price point, so you will be able to find something that works for you. 

There are two main types of shampoos that will clean your hair and get rid of any mildew growing. These are clarifying shampoo and medicated shampoo. In contrast, regular shampoo cleans your hair by removing all dirt and oil from your scalp and hair.

This includes natural, helpful oils as well which can be damaging when trying to get out the mildew smell. 

A clarifying shampoo or medicated shampoo will target the problem and help remove it from the source. 

Clarifying shampoo contains ingredients that both attract and remove any dirt or buildup in your hair. These are strong shampoos that will seek out the mildew, mold, or excess oil, and allow it to be rinsed out. 

Clarifying shampoos work well on hair that has mildew due to excessive oils.

They should be used sparingly and followed by a good conditioner as it can be too rough on your natural oils and may dry out your scalp if used consistently.

Medicated shampoo will treat the mildew or mold as a fungus and get rid of it on your scalp. These shampoos contain antifungals, essential oils, or other ingredients that will avoid the natural oils and focus on the mildew. 

Dry shampoos can be both a help and a hindrance to dealing with mildew in your hair. When used after exercising, or when your hair is slightly damp, they can help to quickly dry any moisture and add air flow to your hair. 

If dry shampoos are used excessively or relied upon, it can cause a lot of buildup on your scalp. This buildup can cause moisture retention, mildew to grow, and your hair to smell. Using dry shampoo should be balanced with washing and drying your hair thoroughly.

Generally, you want to look for a shampoo that has any of the following ingredients: 

  • Tea tree oil
  • Grapefruit seed extract
  • Apple cider vinegar
  • Baking soda
  • Chamomile
  • Menthol
  • Witch Hazel

These ingredients will help neutralize odors, stop mildew from growing, and balance the natural oils on your scalp. When paired with a good blow dryer and clean pillows, you will be set to avoid a mildew smell or growth in your hair. 


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