Last Updated on December 2, 2022 by Verna Meachum

If you’ve ever been around mold or mildew, then you know that it can be pretty unpleasant. You know exactly what it smells like, and the sight and smell of it can be pretty off-putting. But can it actually get into your hair?

There’s presently no indication that mold can develop on human hair. However, your hair probably smells moldy due to other fungal infections, such as seborrheic dermatitis or Malassezia yeast.

These fungal infections can cause your scalp to look and feel greasy, itchy, and irritated.

So what can you do to protect yourself? Read on for the ins and outs of mold and mildew in hair!

What is Mold in Hair? And, What is Mildew in Hair?

Mold and Mildew are greenish-yellow soft tissues often growing on spoiled food or leftover fruits. These are fungi (singular – fungus, belonging to a special group of microorganisms).

Mold commonly grows on walls and in cabinets under humid or tropical conditions, which often leads to a foul smell around the affected areas. Additionally, mold can make food items unsafe for human consumption.

Fungus spores are produced in millions by their mother organisms and can be found almost anywhere. These tiny seeds called “spore” travel rapidly through the air.

To inhibit their growth, antimicrobial agents (chemicals that kill or prevent the growth of microorganisms are often used in food preservatives and household cleaners to keep them from growing and spreading.

Did you know that the human scalp harbors millions of microorganisms, including bacteria and fungi? Scientific studies have found the growth of these microorganisms on the human scalp surface.

Wiley Online Library

Malassezia is one particular example of a fungus commonly found on adult scalps that can cause dandruff and seborrheic dermatitis.^1-2

If left unchecked, their rapid growth may lead to an infection and seborrheic dermatitis. This fungal and mold growth on the scalp or hair often produces an unpleasant smell, or makes the hair smelly.

How do fungi grow on the scalp surface, and what are the implications of having these microorganisms? More importantly, how can we prevent their growth or control their colonies?

In order to answer these questions fully, let’s talk about some science.

Mold Growth on Hair or Scalp: Causes

The human scalp is a wet surface area with sebaceous glands located all over it.These glands secrete sebum.

This liquid secretion mainly comprises water along with a wide range of minerals and lipids. The moist scalp surface offers a perfect breeding ground for microorganisms.

Fungus spores grow quickly by feeding on the nutrients in sebum, which is the oily substance that coats scalp and runs down your hair.

There are a few main causes of fungus growth on the scalp surface.

These include:

• Keeping scalp and hairs moistened

• Excessive sebum secretion

• Poor hygienic state of the scalp

• Keeping moistened hair tied up or covered with a cap

It is important to clarify that mold found on spoiled food, fruits, or on the walls of your house is not the same fungus that grows on the scalp surface.

The two are completely different.

While both belong to the fungi family, scientifically, they are different fungi, and have different mechanisms of reproduction that result in different consequences.

Signs of Mold Or Mildew In Your Hair

Fungus growth can be identified by several signs and consequences:

• Mal-odor on hair and scalp

• Careful examination of the scalp shows patches of yellowish material

• Severe growth can form sac-like flakes identified as “dandruff”

• Eventually, severe dandruff leads to a skin infection

What causes a smelly scalp?

Fungi feeds off the nutrients from sebum and dead skin cells, which then causes a series of changes on the surface of the scalp. These changes include oxidation or degradation of minerals, proteins, and lipids.

The chemical changes eventually generate multiple new molecules that cause a foul smell or smelly scalp, similar to having mold on food.

Is This Dangerous? Any potential health risks?

Healthy scalps have a microbiome that is in balance. This means that when our scalp is in a state of equilibrium, the microorganisms on our scalp do not cause harm.

However, an overgrowth of microorganisms on the scalp can change the overall biological and chemical environment of the scalp.

When hair becomes smelly, it begins to cause discomfort for the individual. If the conditions are severe enough, dandruff can develop which makes the scalp sensitive and causes red patches and itchiness.

Extreme cases could become infectious. 

However, one point must be cleared; fungi spores cannot penetrate the human body. They only live on the surface. So, they don’t pose any danger to the human body. 

How to Prevent Fungal Growth

Personal hygiene is key to a healthy scalp. A few easy steps can prevent the growth of harmful microorganisms and keep your hair and scalp in good condition.

Cleanse

Regularly wash hair and scalp with shampoo or clarifying shampoo. Gently massage the shampoo into your scalp and hair, making sure to remove all residue, product build-up, and dandruff. Follow up with a good moisturizing conditioner to detangle the hair.

Don’t leave it wet

Always dry your hair after washing it. Leaving hair fibers wet can accelerate the fungus growth. This is especially true if you tie up wet hair and leave it soaked for extended periods of time or overnight.

Dry hair after working out

Smelly hair is often caused by fungus that thrives in moist, closed humid environments. Think sweaty wet hair under a baseball cap.

If you exercise regularly, you may notice that your scalp becomes sweatier and oilier. This is because dirt, sebum, and sweat mix together to form a film on the surface of your scalp.

When this microbiome is thrown off balance, it can cause an itchy scalp and unpleasant odor.

In order to prevent this, shower immediately after working out. Not only will it cleanse your body, but also restore microbiome balance to your scalp.

If you can’t immediately wash your hair, then dry it off with a blowdryer (which was recommended by my daughter’s dermatologist).

Another tip the dermatologist gave us was to make sure you spray your cap with Lysol to prevent the spread of mold and mildew.

To read more tips on how to refresh curls after a workout, check out my blog, ‘How to Refresh Your Curls Between Washes.’

Also, be make sure to check out my blog, ‘How to Care for Curls Before and After Working Out.’

Anti-microbial products

Common ingredients in hair cleansing and conditioning products, such as botanicals or chemical agents, help to prevent the growth of microbes on both the scalp and hair.

One good example of this is an anti-itch shampoo for people with sensitive scalps.³ These formulations contain anti-fungal active ingredients to control fungus growth.

Among them are:

Natural Oils

Protecting braids or extensions

If you style your hair with braids or extensions, you need to follow an effective hair care routine to maintain a healthy scalp and strong hair fibers.

For braids, leaving it tied up and soaked is not a good idea. Washing it with a co-wash is ideal for cleaning the scalp without disturbing your braids.

In addition, braids require intensely moisturizing products containing humectants and emollients. Thus, natural butter or oils are also recommended to keep the hair well-lubricated and conditioned. 

Hair extension wearers should take extra care to maintain cleanliness and follow their stylist’s advice on product treatment.

To avoid any build up of sweat and sebum on the scalp, regularly massage it with oils and emollients.

Here is a great video demonstrating how to cleanse your scalp without having to take a shower.

If you have braids, locs, or sewn-in hair extensions, cleansing your scalp with Sea Breeze spray is a great way to keep your scalp healthy. This gently removes excess oils and dead skin cells from the scalp, for a more thorough cleanse and healthy looking hair.

Before shampooing, use Sea Breeze astringent for a professional scalp treatment or massage.

Here’s another video on how to remove mildew from sew-ins:

Best Shampoo for Mildew and Mold In Hair

The best way to keep your scalp and hair clean is to shampoo regularly. Look for shampoos with a sulfate-free base and added antimicrobial active ingredients.

The market contains several options to address fungal growth. Bounce Curl offers a sulfate-free shampoo, containing plant-sourced therapeutic essential oils having strong antimicrobial activity. 

Both shampoos below are are effective to get rid of sebum and product build up.

• Gentle Clarifying Shampoo
• Righteous Roots Clarifying Shampoo

The formulations contain Bergamot oil, Grapefruit Seed Oil, Orange seed Oil, and orange peel oils. These citrus-derived oils provide a cleansing aesthetic and improve scalp quality.

Summary

Mold and mildew are fungi. These fungi may grow on the human scalp under moist and humid conditions.

The main cause of fungal growth is a poor hygienic state and leaving hair in a wet state overnight or for the whole day.

This fungal growth on the scalp and hair fibers can leave hair smelly with malodor. Severe cases may lead to yellowish patches on the scalp surface.

This can make the scalp itchy and cause dandruff. In order to keep mold at bay and improve scalp and hair health, it is important to practice good hygiene.

It’s important to wash your scalp and hair regularly to get rid of excess sebum, lipids, and debris. Herbal oils, natural butter, and essential oils can help inhibit mold growth.

Always speak with your doctor or healthcare professional if you’re having recurring fungal growth on your scalp. There may be underlying conditions that need to be addressed, such as a weakened immune system.

Consult your doctor before attempting any home remedies, to ensure they are safe for you and compatible with your current health conditions.

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References

1. Loing, E.; Lamarque, E.; Borel, M., New targets in the battle against dandruff. J. Cosmet. Sci. 2017, 68 (1), 107-113.
2.  Zviak, C., The Science of Hair Care. Taylor & Francis: 1986.
3.  Sanfilippo, A.; English, J., An overview of medicated shampoos used in dandruff treatment. P AND T 2006, 31 (7), 396.