The science of apple cider vinegar hair rinse5 min read

If you’re an avid reader and follower of natural hair care, you might have heard of apple cider vinegar or “ACV rinse” for hair. The ACV rinse typically follows the usual shampoo + conditioner routine a few times a month. Today we dive into the science behind to understand whether ACV rinse works, and if so – how.

What is apple cider vinegar?

Vinegar comes from the French phrase “vin aigre,” which means sour wine. It can be made from nearly anything containing sugar, including fruit, vegetables and grains. Yeasts first ferment sugar into alcohol, which is then turned into acetic acid by bacteria.

The industry makes apple cider vinegar from fermented apple juice. Production crushes the apples for juice, following with the addition of bacteria and yeast. This is in order to start the alcoholic fermentation process, which converts the sugars to alcohol. In the second fermentation step, the alcohol is converted into vinegar by acetic acid-forming bacteria (Acetobacter species), acetic acid is necessary to make vinegar mildly acidic, with a typical pH of 2–3.

(For reference, the pH scale ranges from 0–14:

  • 0.0–6.9 is acidic
  • 7.0 is neutral
  • 7.1–14.0 is alkaline (also known as basic)

The human body is slightly alkaline with a pH between 7.35 and 7.45, while human skin is on average just below 5 (Source)

The invisible helper

Relatively recently, scientists discovered Stratum corneum or “acid mantle” on the outermost layer of human hair and skin (Source). It is mildly acidic 4.5-5.3 increasing by a few points in its lower layers. Majority of shampoos are alkaline, stripping natural hair oils that maintain delicate pH balance in your hair resulting in dullness, dryness and brittleness. Shampoos containing SLS (sodium lauryl sulfate) with alkalinity reaching as high as 11-12 are the biggest offenders.

The acid mantle is also critical to our hair’s appearance, since it contributes to the shine and tactile feel of the hair. The outer layer of the hair shaft, also known as the cuticle, is comprised of tightly packed overlapping scales. The acid mantle is instrumental in making cuticle scales lie flat, which gives hair a shiny, smooth appearance, and protects from moisture loss. Alkaline products disturb and even destroy the acid mantle, leading hair cuticles to “stand up” like bottle brush. Such vulnerable hair structure makes the hair fragile due to moisture loss, increasing its brittleness and loss of shine.

By now you should be convinced that in order to maintain shiny and healthy-looking hair you need to avoid harsh shampoos in order to maintain the balance of your acid mantle. This is where apple cider vinegar comes in. Mildly acidic, it balances out the alkalinity from harsh shampoos and hard water commonly flowing from taps of urban environments cities – making sure that the cuticles of your hair lie flat and retain moisture well.

Why Apple Cider vinegar?

Contrary to a common misconception, apple cider vinegar isn’t “packed” with nutrients. It does have some potassium and traces of Iron and Magnesium, thanks to being made from apples naturally rich in those. Higher quality cider vinegar also has amino acids and antioxidants. However, while not a high nutritional value provider, it delivers the benefits of an acidity regulator. Because it is mildly acidic, apple cider vinegar restores the natural pH of the acid mantle. Exposure to this acidity calms the outer layer of the hair, flattening the cuticle, which results in hair that shines and slides easily, making it less prone to tangling, snagging and therefore – reducing hair frizz.

For those who experience other scalp conditions, for example, dandruff, apple cider vinegar can bring relief due to its anti-viral, anti-fungal, and anti-bacterial properties. In addition to being antimicrobial, apple cider vinegar is also anti-inflammatory agent, which can counteract the skin inflammation that typically precedes dandruff and a dry, flaky scalp.

Finally, apple cider vinegar can help removing product build up – a direct result from using silicone-based products in your hair care routine.

Easy recipe for ACV hair rinse

Mix 1/2 to 4 tablespoons (5-60ml) of good quality ACV with a large glass of water (8 ounces / 250ml) in a plastic squeeze bottle, spray bottle or other container.

Experiment to find a dilution that works best for your hair type. As a rule of thumb, dry hair likes less ACV and oily hair like more.

  • After shampooing and conditioning, pour the mixture over your hair evenly, working into your scalp.
  • Let it sit for a couple of minutes.
  • Rinse it out

You can add a couple of drops of your favourite essential oil, we recommend peppermint oil – to help mask vinegar smell. However it tends to disappear quickly as the hair dries.

Have you tried ACV? Tell us your opinion in comments!

Who we are:

The Hair Fuel is an all-natural hair growth mask created by Laura Sagen, who lost a third of her hair after a terrible visit to a hairdresser while suffering from a life-long condition of PCOS associated with androgenic hair thinning. She developed the formulation rooted in science of scalp blood flow, which has become The Hair Fuel growth mask. Since then, her company has helped thousands of people like you to start growing healthy hair.

We work closely with our lab and manufacturers to ensure the highest quality product. But a product alone is never enough – so we hold your hand throughout your own, unique hair growth journey. Our flagship product, The Hair Fuel mask coupled with tailored advice, digital tools and online support are there to help you grow the best hair you can. It’s a big claim – but we’re unafraid to make it. Check out our starter bundles >>


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8 thoughts on “The science of apple cider vinegar hair rinse<span class="wtr-time-wrap after-title"><span class="wtr-time-number">5</span> min read</span>”

  1. Wow! Thank you so much for the comprehensive post. I have always heard that apple cider vinegar can help my hair health in many ways but I kept doubting it because I can’t ex[lain how. So I decided to do some searches. And it was really worth it. You have just made everything simple to me,
    Now, I can consider adding it to my hair routine treatment.
    Thank you so much.

    • You’re welcome! Glad you found this helpful. Good idea to use it regularly, but no more than once or twice a month, as otherwise hair can become brittle. Definitely worth it – especially that it’s so cheap, too 🙂

    • Hey Amit! Reduction in melanocytes’ activity in your scalp is what causes graying of the hair. Once melanocytes stop producing pigment which gives hair its colour, it turns gray. The key is to focus on supporting the lifecycle of melanocytes – which means focusing on scalp and hair root, rather than the hair shaft (which is what ACV mostly does). And it goes both ways, applying something to the length of your hair wouldn’t affect the melanocyte function. Hope this helps!

    • Hey Joshua, we would suggest seeing a dermatologist before trying ACV to understand the reason for flaky scalp first. Because the rinse does dry your hair strands if used too often that can lead to hair breakage, we would not recommned it more often than 2-3 times a month.


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