Top 3 Recommended Testosterone Boosters
The Best Natural Testosterone Boosters
LAST UPDATED: September 2018.
By utilising his proven analytical skills in his career and underwhelmed by many products Ben established this site to understand and expose what exactly is included in the supplements you are using.
This page is supported by 24 scientific studies cited at the bottom of the text.
Best of the Boost
We outline the most effective natural testosterone boosters on this page to help you make the best and informed choice.
Each product has been reviewed with hours spent researching each individual ingredient to understand how they work and what benefit they posses for the user.
Anecdotal evidence is avoided and cited references to reliable and reputable study sources are included.
So, why do you need a testosterone booster?
Testosterone is the vital sex hormone steroid for men. It has an effect on many physiological functions.
The synthesis of testosterone is mainly in the testes via the Leydig cells. It is important that we maintain a high level of natural testosterone as it can effect everything from muscle to brain function. 
With this in mind…
Do you feel like have hit a plateau with your training and that you just cannot get past that particular weight in the gym on the bench or squat?
Do you feel like you are not getting any bigger or putting on extra pounds of muscle?
Are you finding it difficult to maintain muscle or particularly difficult to get back to top flight performance after injury?
Or do you feel a little bit lethargic and your libido is suffering?
This is exactly how I started to feel around the age of 31.
If you have answered “yes” to anyone of these questions, chances are you are suffering from low T.
This is a completely normal and natural process. As we age we produce less testosterone, it is that simple.
‘Testosterone levels peak by early adulthood and drop as you age—about 1% to 2% a year’ 
Wouldn’t it be much better to be able to reverse these effects and feel:
- Increased strength
- More active libido
- Increased stamina
- Build more muscle mass
- Lift your mood
You can Effectively, Legally and Safely Treat Low T Without Hormone Replacement Therapy On Prescription…
|Top 3 Test Boosters||
*Best On The Market*
#2 Prime Male
|Capsules Per Day||4||4||4|
(From USA & UK)
|Manufacture location||USA & UK||USA & UK||USA|
(With 3 Box Deal)
(on selected purchases)
|Ordering process||Direct from manufacturer||Direct from manufacturer||Direct from manufacturer|
|Natural & Legal||Yes||Yes||Yes|
|Price & Payment||$65.00 (multi-buy offers available) Pay via paypal or 9 currencies||$69.00 (multi-buy offers available) via paypal or 4 currencies||$69.95 (multi-buy offers available) 5 currencies|
|Increases free test?||YES – Excellent performance||YES – Fantastic results||YES – Super product|
|Full Review||Read Review||Read Review||Read Review|
Best Testosterone Boosters Video
As already mentioned, I have spent countless hours researching and combing through each individual ingredient included in these products to establish the facts and the fiction.
I also use these products to help improve my performance in the gym and on the rugby field.
#1 – TestoFuel
The No.1 Natural Testosterone Booster on the market.
Why you will love TESTOFUEL
TestoFuel helped me:
- Build muscle
- Increase strength
- More energy
- Improve mood
TestoFuel is a great product with a plethora of working (100% natural) ingredients supported by research and scientific studies.
- 2300mg of D-Aspartic Acid – That’s worth 3 ounce of lamb!
- Money Back Guarantee
- 5000IU Vitamin D3 – The equivalent of 14 ounces of cooked salmon!
- Zinc, Magnesium, B6 included
This includes 9 proven ingredients with a four daily servings exceeding a large 3000mg per day which is much more than others.
It also includes ZMA ingredients which form the back bone of any proven and effective testosterone booster.
It also includes ingredients such as D3 and D-Aspartic Acid which are well renowned for their testosterone stimulating benefit.
Then there’s other ingredients that are less commonly found in other testosterone boosters but are also beneficial and proven to stimulate testosterone such as:
- Panax Ginseng
However, more importantly and what really sets TestoFuel apart from the competition is that not one ingredient is included based purely on anecdotal evidence, hear say, folk law or legend.
There’s nothing present based upon ancient rituals or herbal remedies, each ingredient has publicly available and reputable studies demonstrating that they can stimulate hormone production.
There are too many testosterone boosters on the market that include unproven ingredients that offer no benefit and can potentially be harmful.
Ingredients such as Tribulus that are proven not to be effective at stimulating testosterone production still feature heavily in products due to nothing more than rumor.
Not only that, tribulus can be dangerous, cause a number of health issues including toxicity and reports of fetus development problems. 
TestoFuel can improve testosterone levels, improve mood, increase libido and even increase bone density fighting off osteoporosis because of its list of ingredients that have clinical backing.
Myself plus thousands of other guys including golden era bodybuilder Robbie Robinson use this to increase testosterone levels for strength, size or just to feel better.
I would have liked to see the addition of Vitamin C and perhaps and anti-inflammatory such as Boron.
This is only available online direct, so you may need to plan a bit more advance for a re-sup.
This is a premium product with excellent ingredients, so it is not the cheapest, but that means you do not have to buy different products.
I packed on 16lbs of lean muscle. Read my review.
More importantly it helps my recovery, even moreso now I am doing more running for my Army training.
The real king of T-boosters!
Head straight to their website: >>www.TESTOFUEL.com<<
#2 – Prime Male
Why you will love Prime Male
Prime Male has supported me to:
- Increase libido
- Increase vitality
- Increase testosterone
- Reverse muscle loss
Prime Male is aimed more specifically at the older man who wants to benefit, not necessarily from just packing on huge slabs of muscle, but rather the increased energy levels, increased libido and reversed muscular dystrophy that becomes common as men age.
- Formulated for older men
- 1600mg D-Aspartic Acid
- Backed by ex-NFL players
- Boron to reduce inflammation
It packs a massive hit of 12 scientifically proven booster ingredients which are 100% natural and suited to even the most ardent gym rat thanks to the anti inflammatory ingredient: Boron.
It is always a bit of a toss up for me between TestoFuel and Prime Male.
I really like both and I like the slight variation and additional ingredients Prime Male offers.
As already mentioned Boron is a good anti-inflammatory which can help prevent chronic diseases such as obesity as well as increasing testosterone level.
Too much inflammation also inhibits testosterone production which can cause an unwanted hormone imbalance.
There’s also Nettle and Luteolin, which again both help fight this hormone imbalance so testosterone levels can thrive.
Mucuna Pruriens helps regulate stress levels too, because too much stress leads to lower testosterone levels.
I was stressed for approximately 3 years and it diminished my test levels and my gym progress.
The ingredients of B6, Zinc and Magnesium are also present which makes up the ‘ZMA’ complex as seen in TestoFuel but there’s also BioPerine which helps your body absorb all of the nutrients to ensure best bang for your buck.
There’s no point having a wealth of effective ingredients if your body doesn’t absorb them all.
As with TestoFuel, this company also provide you with a money back guarantee.
This product really helped me recover when I was suffering from a recurring rotator cuff injury from playing rugby.
As with TestoFuel, this is online order only so you may want to buy in advance to allow for postage times.
There’s a wealth of ingredients available and that doesn’t come cheap, but at least you know what goes in to a full bottle of this natural test booster.
While this seems to be marketed towards older gentlemen; women and younger guys can use it too, so don’t be put off.
There’s less D-Aspartic Acid than TestoFuel.
Read my review here.
You can head straight over to their website: >>www.PRIMEMALE.com<<
#3 – TestRX
No.3 recommended natural test booster.
Why you will love TESTRX
TestRX has enabled me to:
- Feel more energy
- Cut fat
- Increase natural test
- Sharper mind
As with TestoFuel and Prime Male, this product offers a broad range of clinically proven ingredients with cited references available in the review.
This is only forced to 3rd place due offering a fewer number of ingredients.
It should have included Boron and Ginseng too if it was to be more competitive.
- 2300mg D-Aspartic Acid
- High dose
- Great for all guys
The recommended dose of 4 tablets daily with over 2800mg per daily serving is great.
Strong doses of D3 and Fenugreek plus D-Aspartic Acid make TestRX a viable contender and one to consider.
It is also worth noting, that with the best testosterone boosters, this also includes the foundation of Zinc, Magnesium and B6.
Plus, like the other contenders on the top two podiums, there’s no proprietary blend either.
This means we known exactly how much of each ingredient is included so were are not being ripped off.
There’s also no need to mix and match different supplements to get the vitals that we need to increase those natural T levels.
This top three is bombarded with products that can only be bought direct.
That means you can’t pick up a pack from Walmart or go buying lots of supps from Walgreens at once.
It does mean we know of the source and to eliminate counterfeit products though.
It does offer a less amount of ingredients compared to TestoFuel and Prime Male which means it won’t have as much effect, but it still packs a strong punch.
Head straight to TestRX website direct: >>www.TESTRX.com<<
I have heard about TRT, what do I need to know?
If you think your natural testosterone levels are abnormally low, this is termed hypogonadism.
This is not to be mistaken for the andropause which refers to the natural decline of testosterone your body releases in to your system as you age.
You may have noticed some of the following side effects, or more than likely, your partner and others around you have possibly noticed a change…
Here are some signs to look out for… 
- – Despondency
- – Weariness
- – Hopelessness
- – Lack of focus
- – Insomnolence
- – Brittle bones
- – Muscle waste
- – Overweight
- – No libido
- – Impotency
However, you should certainly seek medical advice to confirm whether you have hypogonadism or suffering from andropause.
If you are suffering from hypogonadism you need to seek medical advice and usually a blood test will be taken to check the figures.
If you do have abnormally low testosterone, it will be necessary to increase your test levels.
Some people may wish to use testosterone replacement therapy.
Low test can have a major impact on not just your sex life and energy levels but also other important areas of your health such as:
- metabolic syndrome
- type 2 diabetes
Increasing your test levels can have a huge beneficial impact on your mental, physical and physiological functions.
These are the main forms of TRT which you can discuss with your Doctor: topical (via creams, patches or gels) and injections.
Like any medical intervention, testosterone therapy or replacement treatment does not come without risks and side effects. Here are the most commonly reported ones.
1. Testosterone therapy can increase your risk of blood clots and even stroke (through increased red blood cell counts).
2. You could experience skin issues including acne
3. Your sleep may be affected (sleep apnea is a commonly reported side effect)
4. TRT can lead to enlargement of male breast tissue.
5. The links to increase prostate cancer risk are thought to be very low, but more research is needed in this area. If you go on TRT, get regular checks.
And it’s addictive, too.
In fact, the main risk of being on being on testosterone therapy is that it is hard to come off it once you start.
Once you are on it, your body will stop making its own testosterone all the while that you are taking TRT.
Going on hormone therapy is a serious and long term decision, and not one to be taken lightly, not when there are natural safe alternatives that you should try first.
The Best Natural T Boosters Trialed And Used By Myself
You may actually be suffering from andropause, also known as hypogonadism too; this is the gradual decline of testosterone as you hit the age of around 30. 
However, sometimes you do not notice it yourself, in some cases it is your partner that does.
You will start to notice a loss of muscle mass, increased fatty deposit build up and it can also effect your mood and libido, you may not find your partner physically attractive anymore which can damage relationships.
However, there is a prescription free and natural option that can slow down the effects of testosterone loss and even reverse them.
There’s also no need for expensive hormone replacement therapy in most cases because testosterone boosters stimulate more natural production of testosterone.
A natural test booster can help you!
Without such you will not be able to naturally raise your testosterone levels quick enough once your cycle has finished to retain that strength and size.
I want to offer you sage advice on what supplements, routines, exercises and food you should be utilizing for optimum gains in and out of the gym which can improve your quality of life and increase muscle.
Natural testosterone boosters are a great way to trigger testosterone production, naturally. In conjunction with a booster, a good weights program hitting the big compound lifts will help you build muscle, cut fat and increase your strength.
What are the Low T symptoms?
For quite a while I was struggling with 308lbs on the bench. I just could not get past it regardless.
I could not put any more weight on and felt like I was stagnating at no heavier than 170lbs. It frustrated the hell out of me.
This was also affecting my other lifts too, I just felt like there was an immovable wall or object in my path.
It is now nice to be hitting 440lbs and still improving.
Alternatively, it could be that you have found yourself now seemingly stuck in the drudgery of work and family life with an overwhelming feeling of lethargy, being moodier, low libido and finding that your muscle mass has been replaced with softer arms, chest and stomach?
With age comes the gradual decline of testosterone, it is a bit like the male equivalent of menopause that women suffer from, however, it is much more gradual and less of a smack in the face.
In most cases, due to the gradual nature of andropause, many men never even recognize the symptoms or do not relate the ‘typical’ aging ‘dad’ bod with testosterone or hormones.
Have you noticed you are more irrational? A bit less impatient? Old man syndrome who is ratty and says his mind without a care for the consequences?
Are you more harsh to your partner and make snide little cutting remarks to make them feel a bit upset too? Or have you stopped complimenting them or jealous of their happiness?
Or do you just feel a little down and low all of the time? Maybe not depressed but just feel flat?
Again, testosterone has an effect on your mood. It can diminish your outlook on life. You may start to lose your enthusiasm and just settle in to the drudgery of routine with little desire to escape.
Okay, this has hit me in the past, hard.
Have you noticed you just don’t have the same desire for sex anymore?
Beforehand you were jumping on your partner; sex in the shower, sex in the car, over the banister in the hallway, in the kitchen and occasionally in your bed?
If sex wasn’t available were you masturbating? Or sometimes thinking of people you fancied while day dreaming at work?
Yet now, you just don’t have that spark?
Again, do you feel flat and a little bit numb to sex. Does your partner mention anything or try to instigate sex or spice the relationship up yet you’re just not interested?
Or do you struggle to maintain a hard erection?
All of this has happened to me in the past. It is a killer.
You may feel that you are just not attracted to your partner anymore, and they will certainly feel the same which can strain an otherwise loving relationship.
However, testosterone, or rather a lack of testosterone can be the root of the cause, and the problems.
One thing I noticed was a build up of fat around my lower back. It wasn’t that I was getting fat and obese, but I would just put a bit of ‘timber’ on then find it extremely hard to shift, so much so that it wouldn’t shift at all.
Testosterone can regulate fat levels too, naturally, men carry more lean muscle and less fat than women.
If you are noticing fat build up, this again, can be partly responsible for a hormone imbalance.
How are your energy levels? Lethargic and lack of energy to hit the gym?
Lack of energy to take your partner out for that date that you promised 5 weeks ago?
Or are you just generally feeling sluggish and like you are dragging yourself around unwillingly through life?
Or rather you have taken the back seat and life is dragging you around?
Have you lost your ‘alpha’?
If you play sport, this can be a big issue.
I play rugby and nearing the age of 34 the difference between able to recover after a game now compared to when I was under the age of 30 is like the difference between black and white.
I simply could not lift any weights until around Thursday after playing on a Saturday.
Normally rugby training is on a Tuesday and Thursday evening yet I simply could not train. My limbs were extremely sore and aching.
My joints also were suffering and injuries just hung around for much longer than they would have done even just 5 years ago.
It actually made me feel quite depressed.
a) walking around like John Wayne for 9 months of the year
b) unable to hit the gym properly during the week
c) sore joints and limbs constantly nagging at me to stop
Have You Taken Steroids or Prohormones?
Once again, I am guilty of this too. In fact my short journey is well documented on here.
When you take steroids or any anabolic be it injected or orally via tablets or pills you are replacing your bodies own naturally produced testosterone with much higher levels of synthetic testosterone.
Your body recognizes the overload so ‘shuts down’ production. You may feel an off sensation in your testicles when this happens, especially the first time. This is them effectively deactivating.
When your course/cycle is over and provided you take a break between cycles your own naturally produced testosterone is no longer being produced.
So, it takes a while for your body to recognize that it now needs to start producing it as the synthetic overload of testosterone has stopped.
This period of ‘post cycle’ will leave you extremely depleted and the symptoms of low testosterone are exaggerated this can lead to:
- limp dick
- no desire for sex
- muscle loss
It can take over a month for your natural testosterone levels to rise again, that’s a long time and depending on your relationship status, it can be cause for concern…it certainly was for me.
In fact, prolonged, uncontrolled and un-prescribed anabolic steroid use can lead to hypogonadism. 
What Causes Low T?
Age is the most common factor causing testosterone levels to naturally decline. So, in reality, it is going to affect us all at some point.
This natural process is called the andropause and its effects are most noticeable in men when they hit their 40s or 50s.
However, the reduction in testosterone can happen as young as 30 where men will experience a decline as much as 2% every year.
Many people think that stress, depression or anxiety causes testosterone levels to decline, however, this is not the case.
However, these factors can cause symptoms similar to low testosterone but are often mistaken for other reasons such as blood vessel problems or other psychological issues. 
This reduction in testosterone is completely natural and happens to all men.
According to the Boston University School of Medicine Hypogonadism affects up to 5 million men in the US are estimated to be affected by this condition.
And, hypogonadism is not just the same as the natural decline of testosterone that is experienced with age. This is a hypogonadism is a health condition.
This condition is where the testes are producing much fewer or no hormones at all. That is, the gonadal function is not working sufficiently from testicular failure and/or dysfunction of the hypothalamic-pituitary axis. 
Hypogonadism can be traced back to birth or it can be caused by health issues such as type 2 diabetes and obesity.
How do testosterone boosters work?
By feeding your body with a number of proven ingredients that are able to stimulate and encourage an increase of testosterone production.
The correct ingredients and nutrition encourages the brain and glands to produce more testosterone.
- Without an effective and healthy nutrition plan in place your body cannot optimally operate and produce the maximum amount of testosterone.
- A T-Booster fills the gaps and ensures you are getting the nutrients that are best for increasing testosterone levels.
Good testosterone boosters reduce the amount of Sex Hormone Binding Globulin (SHBG).
- Did you know that over 50% of the testosterone you produce is not available for use?
- This is because it is bound to SHBG and that means it is not free to increase muscle or provide any other anabolic effects. 
- Test boosters prevent this binding process so it is freely available.
- Estrogen is a female sex hormone, but men naturally produce it as well.
- Too much estrogen will enhance female characteristics such as increased fat levels and breast tissue development. Estrogen dominance will also exacerbate impotency.
- There is an enzyme called aromatase which even converts testosterone to estrogen.
- Some testosterone booster’s have ingredients to control estrogen development.
Which are the key ingredients?
There are many ingredients that are proven to encourage testosterone production and regulate estrogen.
Many of which you may be surprised to hear, however, there are also many ingredients that are not effective or are built around anecdote and legend.
You must avoid these ingredients as they offer nothing, yet many ineffective and un-researched products still contain them.
Look for a testosterone booster which include some of the following nutrients:
- D-Aspartic Acid can increase total testosterone levels in men, particularly those who are new to resistance training 
- D-AA stimulates a release of hormones from the brain
- It is considered that DAA can build up in the testes helping secrete more testosterone 
- While researching vitamin D3 there’s a study that demonstrated that D3 supplementation increased testosterone levels in men compared to the placebo group  
- Clinical trials also illustrated a trend that showed men who have low vitamin D3 levels were at a higher risk of hypogonadism 
- A 5 year study by the University of Leeds in the UK found startling improvements in the pumping ability of the patients (suffering heart failure) who were being administered vitamin D3. 
- In a study concerning men who took 10mg of Boron a day they saw their estrogen levels drop and their free testosterone rise.
- Boron also acts as an anti-inflammatory; too much inflammation inhibits testosterone production and can increase the risk of chronic diseases such obesity. 
- Boron has also proven to increase testosterone levels in postmenopausal women. 
Which ingredients don’t increase testosterone?
The problem with food supplements is that they do not fall under strict guidance principles which means many ingredients can simply by included within supplements with little official intervention.
Then when combined with a proprietary blend it is simply a free for all for anyone to release a product to the suspecting public.
These can also include either dangerous ingredients or just simply ingredients without any real substantial research in to their effects.
However, you are more at risk from supplements that simply include ingredients that have legendary status yet the science proves otherwise.
So, here’s a few common ingredients that are really not very helpful, so just do not bother if you see these on the ingredient panel.
- A mistake I made when new to supplements was believe the hype about how effective tribulus is for raising testosterone. It doesn’t.
- No study has confirmed that taking a tribulus supplement will increase natural testosterone levels. 
- In fact, there is a study on professional Australian rugby players that proves that taking tribulus does not work. 
- As we age DHEA levels naturally decrease, and DHEA is used by the body to produce androgens, as such a decrease is associated with low hormone levels.
- No studies can confirm that taking DHEA supplements actually reverses the trend, therefore, it won’t help increase muscle growth.
- Also known as Wild Yam extract in some products.
- At best, DHEA supplements may help reduce abdominal fat. 
- It is theorized that the sterols in sarsaparilla can be used like a steroid to convert to testosterone.
- This is a false claim and is not true according to tests. 
Horny Goat Weed
- Widely popular and found in lots and lots of test booster supplements that in some circumstances can seem like it will be effective at increasing T levels. 
- It seems to be an aphrodisiac rather than a testosterone booster and may also improve bone health although the evidence is not particularly strong. 
Abieta-8 11 13-trien-18-oic acid (Dehydroabietic Acid)
- Claimed to be anti-estrogenic. If we have an imbalance of male and female sex hormones it will have an effect on the benefits that come with testosterone.
- At best this will help lower estrogen but claims that it can act like a steroid are un-true.
- It does have anti-inflammatory effects that can help treat or prevent obesity. 
Big brands = Big fail
There are many testosterone boosters from many well established ‘traditional’ bodybuilding brands on the market which can cloud your judgement by offering hugely different ingredients.
Yet, the market is awash with products from famous, long standing brands that almost seem not to be bothered with the content of their supplements because their name and heritage alone sells itself, regardless of performance.
The Right Ingredients
Clinical studies and research has identified a select number of ingredients which have proven, when combined in the correct ratios to stimulate your own body to produce up to 42% more testosterone which will regain strength, libido, lean muscle mass and energy.
What is remarkable are the sheer number of products available in stores or on-line that do not include any of these identified proven ingredients and instead rely on anecdotal ‘evidence’ as well as masking the real ingredient levels with a proprietary blend.
A proprietary blend enables the supplement manufacturers to essentially conceal the amount of each ingredient included in that product.
Bulking agents don’t cost as much as D-Aspartic Acid…
These products need to be avoided.
An additional consideration is the legality and safety of some products.
I have tested a huge amount of supplements and on a good number of occasions there have been instances where synthetic chemical compounds are included.
These can not only be illegal in some countries/states but also feature on the banned substance list; if you play sport this could ruin your career or any future aspirations, not to mention the health implications.
Region of Manufacture
Patriotism aside, where would you like your supplements to be manufactured?
Supplements are going to be digested in your body, there is a high level of trust involved. You want the facility where it is manufactured to be clean and safe. You want good manufacturing practices to be adhered to.
You do not want contamination from other ingredients and you want to ensure that what you are taking contains what is on the label.
Therefore, naturally, you want your supplements to be manufactured in a responsible and regulated region.
This would be North America, Europe or places like Australia. Stringent rules, laws and regulations enforced ensure the safety of your health.
Do not be tempted by supplements that ‘offer’ the same but are manufactured in other places that are notoriously less regulated and do not strive or not renowned for quality control.
So, through thorough research and my own real life physical testing I have found out which ones actually perform and what are worth you hard earned cash.
 Androgen deficiency in the aging man. Arianayagam R, Arianayagam M, McGrath S, Rashid P. Aust Fam Physician. 2010 Oct;39(10):752-5. PMID: 20890477
 Tribulus terrestris-induced severe nephrotoxicity in a young healthy male. Talasaz AH, Abbasi MR, Abkhiz S, Dashti-Khavidaki S. Nephrol Dial Transplant. 2010 Nov;25(11):3792-3. doi: 10.1093/ndt/gfq457. Epub 2010 Jul 28. PMID: 20667992
 Late-onset hypogonadism in the aging male (LOH): definition, diagnostic and clinical aspects. Schubert M, Jockenhövel F. J Endocrinol Invest. 2005;28(3 Suppl):23-7. PMID: 16042356
 Anabolic steroid-induced hypogonadism: diagnosis and treatment. Rahnema CD, Lipshultz LI, Crosnoe LE, Kovac JR, Kim ED. Fertil Steril. 2014 May;101(5):1271-9. doi: 10.1016/j.fertnstert.2014.02.002. Epub 2014 Mar 14. Review. PMID: 24636400
 Resistance training increases SHBG in overweight/obese, young men. Roberts CK, Croymans DM, Aziz N, Butch AW, Lee CC. Metabolism. 2013 May;62(5):725-33. doi: 10.1016/j.metabol.2012.12.004. Epub 2013 Jan 12. PMID: 23318050
 Topo E, Soricelli A, D’Aniello A, Ronsini S, D’Aniello G. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. Reproductive Biology and Endocrinology. 2009;7(120):
 Effect of vitamin D supplementation on testosterone levels in men. Pilz S, Frisch S, Koertke H, Kuhn J, Dreier J, Obermayer-Pietsch B, Wehr E, Zittermann A. Horm Metab Res. 2011 Mar;43(3):223-5. doi: 10.1055/s-0030-1269854. Epub 2010 Dec 10.
 Serum vitamin D levels and hypogonadism in men. Lerchbaum E, Pilz S, Trummer C, Rabe T, Schenk M, Heijboer AC, Obermayer-Pietsch B. Andrology. 2014 Sep;2(5):748-54. doi: 10.1111/j.2047-2927.2014.00247.x. Epub 2014 Jul 16. PMID: 25044703
 Nothing Boring About Boron. Pizzorno L. Integr Med (Encinitas). 2015 Aug;14(4):35-48. Review. PMID: 26770156
 A systematic review on the herbal extract Tribulus terrestris and the roots of its putative aphrodisiac and performance enhancing effect. Qureshi A, Naughton DP, Petroczi A. J Diet Suppl. 2014 Mar;11(1):64-79. doi: 10.3109/19390211.2014.887602. Review. PMID: 24559105
 Tyler’s Herbs of Choice: The Therapeutic Use of Phytomedicinals, Third Edition By Dennis V.C. Awang
 Liu WJ, et al. Effects of icariin on erectile function and expression of nitric oxide synthase isoforms in castrated rats. Asian J Androl. (2005)
 Tian L, et al. Effects of icariin on the erectile function and expression of nitrogen oxide synthase isoforms in corpus cavernosum of arterigenic erectile dysfunction rat model. Zhonghua Yi Xue Za Zhi. (2004)
 Dehydroabietic acid, a phytochemical, acts as ligand for PPARs in macrophages and adipocytes to regulate inflammation. Kang MS, Hirai S, Goto T, Kuroyanagi K, Lee JY, Uemura T, Ezaki Y, Takahashi N, Kawada T. Biochem Biophys Res Commun. 2008 May 2;369(2):333-8. doi: 10.1016/j.bbrc.2008.02.002. Epub 2008 Feb 11. PMID: 18267111