PGD2 inhibitors

Pgd2 Natural and Non-natural Inhibitors

As a relative newcomer on the hair loss scene, PGD2 is a form of prostaglandin that attaches to a receiving cell called GPR44. When it does this, it causes changes in the hair follicles that make your hair more likely to fall out. It’s more prevalent and important for those of us who have androgenic alopecia, aka male-pattern baldness.

Since discovering it, scientists have continued working to find ways to inhibit it. In other words, they want to stop PGD2 from reaching GPR44. There are two ways to achieve this: through reducing the amount of PGD2 that’s present in the first place or introducing a blockade that stands between the prostaglandin and its receiving cell.

While blocking PGD2 won’t benefit all types of hair loss, we have found plenty of scientific research to support the idea that it’s useful for those who have hereditary/androgenic hair loss. Before you decide whether to introduce PGD2 inhibitors to your hair regrowth regime, we need to explain what it is, how it works, how to block it, and who will benefit.

What is Pgd2 and why do you want to inhibit it?

As we’ve already explained, PGD2 is a prostaglandin that leads to hair loss in those with male-pattern baldness. Scientists first discovered this at the University of Pennsylvania, where they found that those with androgenic-alopecia had a higher amount of the compound present in their hair than those without the condition. They also found that it works in synchrony with testosterone. As we all know, testosterone plays a big role in tinkering with the hair’s follicles and making male-pattern baldness more likely.
So, if PGD2 works alongside testosterone to induce hair loss, there’s a strong case for inhibiting it. However, we’re not sure exactly how it has its effects. Some of the common theories circulating the medical world include:

  • Like the DHT form of testosterone, it makes your hair’s follicles smaller. As a result, they’re less likely to produce thick hair.
  • Similarly, it moves them into the telogen phase of growth, which is where they remain dormant.
  • Finally, like all prostaglandins, it’s an inflammatory agent. If it’s acting around our scalps as the scientists from the University of Pennsylvania claim, this means it may block them from receiving the nutrients they need to reach their full potential.

Combined, the above three factors allow for a perfect storm. If your hair’s follicles are smaller, spending more time in the telogen phase where they remain dormant, and lacking in nutrients; your hair isn’t going to have an easy time growing.

Which natural Pgd2 inhibitors are available?

From foods through to supplements, there are lots of natural PGD2 inhibitors floating around. The one you choose may depend on other products you’re using to treat hair loss, so always check to ensure they don’t interact with any ongoing treatments before using them.

Castor oil and PGD2

One study has found that castor oil’s components act as a natural PGD2 antagonist. In other words, it stands between the compound and its receptor cell and stops it from reaching it in the first place. Scientists believe this is due to its high ricinoleic acid content. Ricinoleic acid binds to the receptor molecule. So, while you’re not reducing your PGD2 levels as such, you are stopping them from reaching the area where they cause harm. If you choose to take castor oil as an oral supplement, bear in mind that it causes diarrhea in some patients.

Essential fatty acids

In contrast, essential fatty acids such as omega-3s lead to a reduction in PGD2. Research to back this up comes from the Perelman School of Medicine, where the team found that those taking supplements containing essential fatty acids produced less PGD2. You can find such acids naturally in foods like salmon and flaxseed. However, if you’d rather take a supplement, cod liver oil is also effective. At the same time, cod liver oil reduces inflammation, which may also benefit your hair follicles in terms of gathering strength.

Fruits and vegetables containing quercetin

Quercetin is a compound that gives fruits and vegetables with vibrant colors their attractive appearance. At the same time, quercetin acts as an antioxidant, which means it protects your scalp’s follicles from the pollutants it encounters in day-to-day life. Foods that contain it include onions, sweet potatoes, and cranberry. In one study, researchers found that it actively reduces PGD2 levels. Similarly, quercetin alters your body’s lipid profile so that it attracts fewer androgens, benefiting male-pattern hair loss further.


Luteolin is another substance that acts as a blockade between PGD2 and its receptor cells. It achieves this through producing histamines, which are the chemicals involved in inducing allergic reactions. Using luteolin won’t lead to an allergic reaction. However, one study reveals that it blocks PGD2 levels by up to 100 percent. At the same time, it has anti-inflammatory and antioxidant properties. By reducing inflammation around affected hair follicles and allowing more antioxidants to gain access there, it enhances their health. Theoretically, this leads to better hair growth. We can find luteolin in celery, chamomile tea, and onions.

Which non-natural Pgd2 inhibitors are available?

Before we begin explaining which non-natural PGD2 inhibitors are available, we want to issue a word of caution: many of them are drugs. While you can purchase some of them via a pharmacy, they can still hurt ongoing health conditions. As such, if you want to use them and you are using other medications, you’re due to undergo surgery, or you have a health condition, chat with a medical professional first.

It’s all about the salicylics

In short, non-natural PGD2 inhibitors usually include salicylic drugs. Such drugs include:

  • Aspirin
  • Topical salicylic acid for treating dandruff and other dermatological conditions
  • Benzoic acid, which is an antifungal agent
  • Coal tar
  • Doxycycline, which is an antibiotic
  • Hydrocortisone, which is a steroid

The theory is that salicylic acid containing drugs will stop PGD2 from wreaking havoc, as they are pharmacological prostaglandin inhibitors. They are able to achieve this via something called the ‘cyclooxygenase pathway.’ The cyclooxygenase pathway is a complex biochemical process that involves arachidonic acid converting to PGD2, which then causes inflammation. For many years, drug manufacturers have produced ‘cox-inhibitors,’ which introduce themselves at a stage of the cox pathway to block arachidonic acid from turning into PGD2. This is a very simplified version of how they work, but it does give an overview of how they’re useful.

While you may feel tempted to take doxycycline to see what happens, or to apply aspirin to your head; try to resist the urge until you have the all-clear from a medic. Inappropriate antibiotic use leads to antibiotic resistance and can cause side effects such as diarrhea. Similarly, self-administering medications when you’re already taking something else can affect how effectively it works.

Who benefits from PGD2 inhibition?

So far, each study points towards PGD2 inhibition being a beneficial hair loss reduction technique for those with male-pattern baldness. You may also hear people refer to this condition as ‘androgenic hair loss’ or ‘hereditary hair loss.’

As its inhibition can reduce inflammation and make your scalp’s follicles healthier, it may also benefit those of us who suffer from dermatitis and similar conditions. However, there are few studies demonstrating its efficacy in this role. While one study highlights how the compound may target a receptor cell called CRTH2, it also acknowledges that whether patients will benefit depends on the type of T Helper cells that are present in their bodies at the time. As such, it’s difficult for us to say whether it’s worth your efforts if you have a condition such as folliculitis or atopic dermatitis.

In summary, PGD2 is a prostaglandin that’s found in abundance in the scalps of those suffering from androgenic hair loss. It works alongside testosterone to affect follicle growth phases, inducing inflammatory processes, and reducing follicular size. While there are plenty of natural inhibitors around, do look into whether using them will affect the approach you’re currently taking to reduce hair loss. While we couldn’t find any evidence to support the use of PGD2 in other types of hair loss, there is some evidence suggesting that certain patients may benefit from its use. Finally, when it comes to non-natural inhibitors; exercise caution. Not doing so can have an impact on your overall health.

Written by Robert B. Brown

Dermatologist. Researcher. Writer. There are only two things more important than my beard in life; My wife and my two kids. I'm a guy full of surprise. If you don't hear me talk about my hair or beard, it's probably because I am watching the UFC.

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