A handful of reishi mushrooms

Best Natural 5 Alpha Reductase Inhibitors

5-alpha-reductase (5AR) is an enzyme in the body that converts testosterone into DHT which then goes on to cause hair loss in men affected with androgenic alopecia.

By inhibiting the enzyme we can essentially slow down the production of DHT and thereby prevent hair loss. Here’s the top 4 natural compounds that inhibit 5-alpha-reductase.

Reishi mushroom

Reishi mushroom is one of the new kids on the block when it comes to DHT blockers. It’s not as well known yet, but initial trials are promising as a 5-alpha-reductase inhibitor.

While not many studies have been performed on reishi, there is one that provides some promising insight into this natural inhibitor.

In 2005, Japanese researchers compared 19 species of mushroom to determine their ability to inhibit 5AR. Of these 19 species, reishi was one of them.

The researchers prepared ethanol extracts of the different species, and then added it to a suspension containing rat liver and prostate microsomes. The prostate is one place on the body where DHT is produced, with the help of testosterone and 5AR.

Once the mushroom species’ have been added to the suspensions, the researchers measured their inhibitory effects:

Reishi Mushroom inhibits 5-alpha-reductase, thereby reducing DHT levels in the scalp.

As seen above, reishi mushroom performed the best. It inhibited 5AR between 70% and 80%, which is quite impressive! After all, consider that the next species inhibited up to only 60%, and the number just go down from there.

Even further, researchers wanted to see if reishi was also effective at reducing testosterone levels. A direct measure of this is prostate size.

Using rat prostates, the rats were split into three groups.

The first was a control, while the other two contained different concentrations of reishi: 1.5 mg/kg and 15mg/kg:

Reishi works to reduce testosterone effects on Prostate growth.

While the higher concentration of reishi was almost identical to the results of the control, the lower concentration (1.5mg/kg) significantly lowered the weight of the prostate.

What do these results mean for those with AGA?

It’s well known that testosterone and 5AR play a key role in AGA. More specially, it’s the androgen (DHT) that’s produced from the interaction between them. This leads to hair follicle miniaturization and, if left untreated, irreversible baldness.

By inhibiting the levels of 5AR, you reduce the levels of DHT as a result. This can combat miniaturization and hair loss, all without the negative effects of DHT blockers.

Even better? Reishi has also been shown to benefit the immune system.

This is great news for everyone, but especially those who suffer from immune-related hair loss (such as Alopecia Areata).

Saw palmetto

Saw palmetto is probably the most well-known and also controversial 5AR inhibitor, due to the variation in results and side effects associated with high oral dosages.

Unfortunately this is because most men take saw palmetto orally. Oral ingestion is the least effective way you can benefit from saw palmetto’s inhibitory effect on 5-alpha-reductase because it’s diluted throughout the entire body. A much more effective method is to apply the soft gel capsules topically to the affected areas of the scalp.

And while further research is needed to best understand this plant-derived treatment option, one study does show that a combination of gelatin-cystine and saw palmetto was effective in reducing free radical levels and inducing hair growth.

This study followed 48 volunteers (24 male and 24 female) as they applied the lotion (either active or placebo) over 50 weeks. Some participants (12) also took an oral supplement (which did not contain saw palmetto). All patients were previously diagnosed with AGA, and they ranked anywhere from a stage III to IV on the Norwood-Hamilton scale:

The study consisted of five groups total:

  1. Group 1: Active lotion A;
  2. Group 2: Inactive (placebo) lotion B;
  3. Group 3: Active diet supplement C;
  4. Group 4: Inactive (placebo) diet supplement D; and
  5. Group 5: Active lotion A and active diet supplement C

The lotion was applied twice per day (8AM and 8PM) and the participants were also given a mild shampoo and were instructed to use it throughout the length of the study.

For the hair growth portion of the study, the mean percentage variation of hair number per squared centimeter of scalp was taken.

Now, let’s take a close look at the results:

Saw palmetto hair growth study results

As shown above, all active groups (lotion, diet, and lotion + diet) performed significantly better than the two placebo groups (lotion and diet). The most effective was the lotion + diet group, followed by diet, and finally lotion.

Does this mean that saw palmetto is an effective treatment for AGA hair loss?


Since the study was performed to test both saw palmetto and gelatin-cystine, there’s no way to say which of the two worked best.

Additionally, we do know of saw palmetto’s various other health benefits. For example, it’s been shown to be anti-inflammatory and contain antioxidant properties.

Green tea

Green tea has been consumed for centuries, and it’s even been used in a wide variety of therapeutic and cosmetic products. This is because it has an array of beneficial components (including antioxidants such as EGCG) which make it an effective natural ingredient.

One way in which green tea can be used that you may not know about? To inhibit 5-alpha-reductase!

In 2007, researchers from Seoul National University Hospital in South Korea found that a particular polyphenol – EGCG – may be responsible for its antioxidant properties. Even better? It may also play a significant role in human hair growth by inhibiting 5AR.

To test this theory, researchers extracted hair follicles from scalp tissue specimens supplied by five, healthy men. The follicles were dissected, and were then cut into small pieces (about 2.5mm, including the Dermal Papilla). The pieces were stored in well dishes containing 10 ng/ml hydrocortisone, 10mg/ml insulin, 2 mm L-glutamine, 100µg/ml streptomycin, and 100 U/ml penicillin.

Finally, EGCG was introduced to the specimens at 0.1, 1, or 5 µM.

EGCG green tea hair growth study

The EGCG was shown to clear increase the number of Dermal Papilla Cells (DPCs) present within each specimen, with an increase in cells as more EGCG was introduced.

Even further, the researchers applied EGCG directly to the scalps of healthy men.

When the DPCs were extracted from the scalps, the levels of phosphorylated Erk (P-Erk) was three times what it was in the control group. What does this have to do with hair growth?

The ERK pathway is directly involved in the proliferation of DPCs (and it also modulates 5-alpha-reductase), so an increased presence means increased potential for hair growth.

While further studies need to be conducted, it’s clear that green tea (and its main compound, EGCG) can play a beneficial role in hair health and growth.


Alklaizing the bloodstream by consuming foods that have a net alkaline effect on the body can significantly reduce the amount of type 2 alpha 5 reductase in the scalp.

You should find out what foods have alkalizing properties and increase the proportion of these foods in your meals, and conversely find which foods have acidifying properties and try to eat less of them.

Amazingly this is a method that’s far more effective at inhibiting alpha 5 reductase from creating DHT in the scalp, than any synthetic drug like finasteride.

It’s also completely in line with nature and the only side effects are increased health, energy, metabolism and sex drive. Type 2 alpha 5 reductase is an enzyme that converts testosterone to dihydroxytestosterone.

Some foods cause hair loss, other help regrowth

Enzymes have a very narrow range of pH that they can operate within, and outside this range they can’t do their job. Type 2 alpha 5 reductase operates below neutral in our scalps. So by raising our bodily pH we can directly reduce the amount of DHT in the scalp.

There’s a very easy way to do this and it’s detailed in full in our hair loss course along with detailed tables of alkalizing and acidifying foods, that’s available right now here.

Alkalizing the bloodstream is in my experience the most effective and long term solution for inhibiting 5-alpha-reductase and can have a dramatic effect on preventing further hair loss.

Before the agricultural revolution our diets consisted primarily of highly alkalizing foods. After the agricultural revolution our diets shifted towards acidifying foods like grains.

The overall affect is that many enzymes, which are pH controlled, went out of sync with the body (doing what they weren’t designed to do) and one of the side effects was ‘male pattern baldness.’ I certainly can’t imagine many hunter gatherers with shiny bald scalps or receding hair lines.

Luckily, we don’t have to go back to hunting and gathering all day to reverse our hair loss. We can just copy their diets, which will alkalize our bodies and the effect is the same.

Hair loss isn’t a natural phenomenon, it’s a side effect of our modern diets and lifestyle including high stress levels as well as a genetic predisposition. Here are 4 foods that may contribute to increased hair loss.

It’s now clear that ‘male pattern baldness’ is a fairly modern phenomenon which doesn’t occur in Indigenous populations. The key is that simple changes can make a huge difference and the results are evident within a few months.

*This article was reviewed by Dr. Anil Simhadri

14 thoughts on “Best Natural 5 Alpha Reductase Inhibitors”

  1. Hi im 21 year old i did masterbation many times from 3 to 4 years now i have lose alot of hairs i drink 2 to 3 cups of green tea each day for my balding scalp….now what i can do futher for my hairs…tell me give me some new idea

  2. I have read that Saw palmetto inhibits iron adsorption, how would I prevent this as I am not anemic but am building my iron levels up as women need 80 to have the hair follicle to function and mine is currently 45.

    • My email is will (at) hairguard.com. However, if you have a question I prefer that you ask it in the comments, then everybody can benefit from the discussion, rather than ask it via email.

  3. Hi Will,

    One thing i would like to know about is the alkalising foods listed…I’ve read extensively how foods such kale and spinach are known as goitrogens and inhibit iodine absorption by the thyroid which can lead to an underactive thyroid which in turn can lead to hair loss.

    Do you have any further information on this? I really want to make smoothies with kale and spinach but im scared off by the possibility it might affect my thyroid and cause more shedding…

    • Hi Matt,

      While it’s true that goitrogens can lead to hypothyroidism, the risk is very small. This is especially true if you’re an otherwise healthy adult with no nutritional deficiencies.

      Essentially, the benefits outweigh the risks.

      – Steph

  4. Hi Will,

    One thing i would like to know about is the alkalising foods listed…I’ve read extensively how foods such kale and spinach are known as goitrogens and inhibit iodine absorption by the thyroid which can lead to an underactive thyroid which in turn can lead to hair loss.

    Do you have any further information on this? I really want to make smoothies with kale and spinach but im scared off by the possibility it might affect my thyroid and cause more shedding…

  5. Hello Will,

    I have excessive sebum in my scalp. If I do not shampoo everyday, it becomes very greasy. If I stop shampooing for 2-3 days, I get pain on my hair roots and have heavy hairfall.

    I have consulted doctors, but have not been able to find a permanent solution to this apart from daily shampooing the hair.

    Appreciate if you could guide me in the right direction, what actually the cause may be and what may be done to mitigate this.


  6. Hi Will, I have a condition where sweating quickly leads to itchy scalp . I may also seeing hair thinning. I read your post on re-growing hair, so working on it, can you suggest something related to this sweating & itching thing.

    • Improving your diet is a good first step, that can often help the itching. Also, review the quality of your water, (shower and drinking). Poor water quality can affect your scalp health.

  7. Hi Will,
    I am 24 and having thinning hair and getting worse since 6 months and i am trying to have a well balanced diet and having fish oil supplements and ashwaganda to reduce stress but i am loosing hair continuously even after using organic shampoo and maintaining it well. I am also having decrease in sex drive these days and not sure whats the reason .As a matter of fact i am 200lbs and 184cms height..
    I really appreciate it if you can suggest me any solution.
    Thank You.


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