Caffeine for Hair Growth | A Review of the Research in 2019

Caffeine isn’t just in your morning coffee.

Some evidence suggests that, when used the right way, caffeine could help boost hair growth.

But, how?

We’ve looked at the science to give you all the information you need.

Make sure you read until the end of this article to understand the science behind caffeine for hair growth, why caffeine should be a key part of your healthy hair care routine, and how caffeine compares to other hair treatments.

Quickly, make sure you take the free hair quiz later in this article.

Caffeine for Hair Growth: The Science

Scientific research studies suggest caffeine can support hair growth.

Let’s talk about one promising study that compares caffeine against a popular hair loss treatment.

One Promising Study: Caffeine Vs. Minoxidil

In one study, researchers compared minoxidil and caffeine in men with androgenic alopecia (1). It was a randomized controlled trial (RCT). RCTs are high-quality, reliable studies.

The subjects they included were 161 men with androgenic alopecia aged 18 to 55. One group applied a 0.2% caffeine solution twice per day. The other group applied minoxidil twice per day. Both groups were followed for six months.

At the six month mark, the caffeine group had better results than the minoxidil group. Although, the difference between the two wasn’t hugely significant.

But, caffeine is a natural product as opposed to minoxidil, which is synthetic.

The results of this study suggest caffeine can be used as a natural hair loss alternative to minoxidil.

The only issue with this study is the researchers. The manufacturer of the caffeine solution used in the study was involved in this research. This means that there may have been some unintentional bias the skewed the results.

Although there is a slight conflict of interest, the results are promising!

Key Takeaway: Research shows that caffeine might be a natural, non-toxic alternative to minoxidil.

How Hair Grows

So, how can caffeine grow hair faster?

We examined the science to find the answer.

But, before we get into just how caffeine does it, let’s talk about how hair grows. It’ll help paint a better picture for you to understand how caffeine works.

At the bottom of the hair follicle, there are cells called dermal papilla cells. These are unprogrammed cells that divide to become the hair shaft. Inside these cells, there are tiny molecules that act as signals. They tell the cells whether to die (called apoptosis) or divide (called proliferation).

If the molecules that tell cells to divide are stimulated, cells will divide. This is when hair grows. If there’s no stimulation, cells will die off. This means hair stops or slows its growth.

The structure of the hair follicle as it goes through the growth cycle

Hair growth only happens when cells divide more than they die off.

There are two important molecules that signal dermal papilla cells to divide. These are cAMP and IGF-1.

Cyclic Adenosine Monophosphate (cAMP)

cAMP is a protein that signals dermal papilla cells to divide. It’s balanced out by an enzyme called phosphodiesterase. When cAMP levels get too high, phosphodiesterase digests cAMP (2). More on this later.

So, why is cAMP important?

One of the stimulators of hair growth is a protein called FGF-7 (3). High levels of cAMP in dermal papilla cells upregulates FGF-7 (4). This means that the more cAMP there is in a dermal papilla cell, the more active FGF-7 is. This increased activity leads to faster hair growth.

Key Takeaway: High concentrations of cAMP in dermal papilla cells promotes hair growth.

Insulin-Like Growth Factor 1 (IGF-1)

IGF-1 is a protein found in hair follicle cells. It controls cell death and cell division. Another important protein is PDGF (A and B) that controls cell growth.

In one study, researchers found that IGF-1 treated hair follicles had higher levels of PDGF-A and PDGF-B (5). It also reduced the rate of apoptosis or cell death in hair follicle cells. IGF-1 treated follicles also experienced faster hair growth.

By increasing PDGF-A and PDGF-B and decreasing cell death, IGF-1 plays an important role in hair growth. So, increasing IGF-1 helps promote healthy hair growth.

Key Takeaway: Increasing IGF-1 in the hair follicle impacts the hair growth rate.

Why Is My Hair Falling Out?

There are many reasons for hair loss. There is one theory that relates to caffeine.

This theory is the Scalp Tension Theory of Hair Loss. Below, I’ll explain the details of this theory.

The Scalp Tension Theory of Hair Loss: Androgenetic Alopecia

Androgenetic Alopecia (AGA), more commonly known as pattern hair loss, is extremely common. Both men and women suffer from it.

There are a few things we know for sure about androgenetic alopecia. Sufferers have decreased scalp blood flow and increased levels of DHT, a product of testosterone, on the scalp (6). Researchers believe this could be a result of chronic tension in the muscles of the scalp.

A man massaging his scalp

This is an issue because hair requires nutrients to grow. Certain B-vitamins, minerals, and especially protein are essential. These nutrients are delivered by blood flow to the hair follicles. Essentially, without blood flow, hair can’t grow. This is part of the reason why androgenetic alopecia sufferers experience baldness.

Now, let’s talk about the DHT.

In the cells of the hair follicle and the sebaceous gland attached to it, there’s an enzyme called 5 alpha-reductase. Here’s how it works:

  • Testosterone is delivered to the hair follicle by the blood.
  • Testosterone enters cells in the sebaceous gland and hair follicle.
  • Inside cells, testosterone attaches to the 5 alpha-reductase enzyme.
  • The enzyme converts testosterone into DHT.

When this enzyme gets overactive, it increases the levels of DHT on the scalp. This causes issues like decreased follicle size and increases inflammation and tension in the scalp. Even worse, increased tension can also increase testosterone levels which starts the cycle all over again.

Elevated levels of DHT can also stimulate the production of a protein called Transforming Growth Factor Beta (TGF-β). This reduces blood flow and causes scarring around the hair follicle. This is another cause of decreased hair growth and loss.

All of these factors combined give us an explanation of how hair loss happens.

Key Takeaway: Decreased blood flow, increased 5 alpha-reductase activity, and increased DHT can cause hair loss.

Caffeine for Hair Growth and Hair Loss

Now, you know how hair grows and one of the reasons it stops growing. So, let’s talk about how caffeine can help.

Caffeine stimulates hair growth and regrowth in a few ways:

  1. It stimulates IGF-1 production in hair follicles.
  2. It increases levels of cAMP in dermal papilla cells.
  3. It counteracts the negative effects of DHT.

Let’s talk about each of them.

Caffeine and IGF-1

When caffeine is applied to the scalp, it’s absorbed into hair follicles (7). These hair follicles then penetrate dermal papilla cells.

Research shows that caffeine present in dermal papilla cells can increase follicle levels of IGF-1 in both men and women (8). Like we talked about before, this is important for promoting proper hair growth.

Key Takeaway: By using shampoos or other topical caffeine products, you can increase levels of IGF-1 in hair follicles. Higher levels of IGF-1 equals more hair growth.

Caffeine and cAMP

Earlier I mentioned that cAMP is important for stimulating cell division. This is what drives hair growth.

Remember that enzyme that digests cAMP? Phosphodiesterase? Well, caffeine reduces the activity of this enzyme (2). This means that cAMP can increase in cells without phosphodiesterase interfering.

As phosphodiesterase activity decreases, cAMP activity increases. As a result, more cell division in hair follicles can occur, leading to faster hair growth.

This has been demonstrated in one study, where caffeine shampoo boosted cAMP levels and hair growth rate (9).

Key Takeaways: Caffeine increases cAMP in cells which promotes hair growth.

Caffeine Counteracts the Effects of DHT

Although there’s no evidence to prove the caffeine lowers DHT, it can counteract its negative effects.

It does this in three ways: downregulating TGF-β, improving blood flow, and reducing inflammation (10, 11, 12).

In the next two sections, we’ll talk about why this matters for caffeine and healthy hair growth.

Caffeine Downregulates TGF-β

Caffeine has been shown to downregulate the activity of TGF-β in human cells (10). This molecule is a key factor in hair loss.

By reducing its activity, you can avoid blood vessel calcification and scarring around hair follicles. As a result, caffeine helps to restore blood flow and prevent further damage to hair follicles. This stimulates hair growth and prevents further hair loss.

Key Takeaway: Downregulation of TGF-β is one way caffeine could help prevent hair loss. It could also help you grow hair faster.

Caffeine Improves Blood Flow

We already established that caffeine can increase cAMP which stimulates hair growth. But, increased cAMP also causes vasodilation (11). This dilates blood vessels, increasing blood flow.

One of the major factors in hair loss is decreased blood flow. Now, caffeine doesn’t necessarily resolve the underlying causes of this. But, it does counteract it.

By intervening in decreased blood flow, caffeine can enhance nutrient delivery to follicles. This is exactly what dermal papilla cells that create your hair need. When nutrients can make their way to the follicle through the blood, it gives these cells the essential nutrients needed for function.

The result is faster hair growth, reduced hair loss, and healthier hair overall.

Key Takeaway: Caffeine is a vasodilator, meaning it increases blood flow. This means potentially more nutrients for your hair follicle and more healthy hair growth.

Caffeine Reduces Inflammation

Inflammation is a complex process. The Scalp Tension Theory suggests that scalp tension causes scalp inflammation. But, this inflammation also produces free radicals (13). In turn, these free radicals stimulate more inflammation. It’s a vicious cycle.

But, antioxidants can help in these cases. This is where caffeine comes in. It’s a potent antioxidant (12).

When you use a caffeine shampoo, it gets absorbed into the hair follicles. Then, it comes in contact with the free radicals produced by inflammation. Caffeine will donate an electron to the free radical, which neutralizes it. As a result, antioxidants can reduce scalp inflammation (14).

This can prevent hair loss associated with scalp inflammation.

Key Takeaway: Caffeine is an antioxidant. It reduces inflammation on the scalp which can prevent hair loss.

Why You Should Add a Caffeine Shampoo to Your Healthy Hair Care Routine

By counteracting hair loss and promoting hair growth, some studies suggest caffeine can seriously boost the health of your hair.

Caffeine is easily absorbed by hair follicles when it’s used topically. So, the easiest way to incorporate it into your routine is through a shampoo. I mean, you’re going to use one anyway! It may serve your hair well to incorporate a caffeine shampoo into your routine.

Key Takeaway: You’re going to use a shampoo anyway, so consider a shampoo formulation with a meaningful amount of caffeine as an active ingredient.

Investing Your Money: Caffeine Versus Other Popular Hair Treatments

As always, you want to know where you should invest your money. Caffeine is great and all, but how does it stand up to other treatments?

One thing to keep in mind is that caffeine is natural. It can easily be used with other treatments for even better results.

Caffeine versus Peppermint Oil

Right now, there are no studies directly comparing peppermint oil and caffeine for hair growth.

But, they can be safely used together. Peppermint oil relieves scalp tension and increases blood flow. Caffeine can stimulate hair growth in the follicle. Together, they’re healthy hair powerhouses.

A great way to incorporate the two into your routine is to use a peppermint oil scalp elixir as a scalp mask. Then, use a caffeine shampoo to cleanse.

Key Takeaway: There are no studies comparing the two. But, a peppermint oil elixir and caffeine shampoo may be used together for potential hair growth.

Caffeine vs. Finasteride

Finasteride is an oral anti-androgen drug. It’s used in both men and women to decrease DHT levels on the scalp. Currently, it’s FDA-approved for the treatment of androgenic alopecia.

Studies show that the patient response rate is dependent on scalp levels of IGF-1 (16). In other words, finasteride may work by increasing IGF-1 in hair follicles.

Sound familiar? Caffeine increases IGF-1 in hair follicles, too!

Unlike finasteride, caffeine can be applied topically. And, best of all, it doesn’t have any side effects.

Research suggests that side effects are unlikely with finasteride (17). However, many users report side effects like decreased libido.

There are no studies directly comparing the two yet. In research, it seems that caffeine and finasteride act similarly to prevent hair loss.

But, finasteride is taken orally while caffeine is used topically for hair loss.

Key Takeaway: Caffeine seems to act similarly to finasteride. But, they are used differently and haven’t been directly compared in studies.

The Verdict: Can Caffeine Grow Hair?

There are studies that back the efficacy of caffeine for hair growth. Although, we can’t say for certain if caffeine will grow hair.

The one human trial using caffeine for hair growth showed great results. But, there was a conflict of interest. All other studies are cell culture studies. They are promising but hard to translate to the real world! And there isn’t a ton of data comparing it to other treatments.

Research shows that caffeine may work similarly to minoxidil. But, we need more research. It can also safely be used in conjunction with other therapies for better results.

Have any questions regarding caffeine? Or hair growth in general? Leave a comment below!

About Sophia

Rosemary Oil for Hair Growth: An In-Depth Look

Can Lack of Sleep Cause Hair Loss?