Staminol (or sometimes known as Staminol Ultra) is a said to be an effective formula for men to address male performance concerns. Unlike other fly-by-night male enhancement products, Staminol is manufactured by a legitimate company (none other than GNC) and it’s endorsed by the urological surgeon.
In this post, we are going to take a closer look at Staminol… what’s inside Staminol and does it work?
The key ingredients include:
L-arginine – 1000 mg : L-arginine is an semiessential amino acid. It occurs naturally in many nuts, legume, and seed. Early studies suggest that L-arginine may aid medical condition that improved with increased vasodilation, including erectile dysfunction, heart disease, chest pain and vascular headaches.
However, researcher David Barr argues that L-arginine supplementation doesn’t affect blood flow. 
As well, Examine.com points out that the studies show unreliable results:
“L-arginine is a popular supplement for athletes as it is touted to increase nitric oxide activity in the body. Unfortunately, this effect appears to be unreliable in otherwise healthy adults. While there have been studies that have measured increased effects of nitric oxide (blood flow) they are paired with studies showing no net effects.” 
According to Mayo Clinic, the therapeutic dosage for L-arginine is 400-6000 mg.
Note: Citrulline is a better booster of blood arginine than L-arginine supplementation.
L-arginine may cause side effects such as: bloating, diarrhea, nausea, numbness, increase risk of bleeding, change in blood sugar level, etc.
Also, if you have high blood pressure or existing heart conditions, you must can talk to your doctor before increasing nitric level.
Maca root powder – 100mg: maca traditionally grows in Peru. It has been used as herbal medicine for menopausal discomfort, infertility, and sexual healing. At least three studies  have confirm its libido-boosting effect.
As well, Maca appears to improve erection quality in men with mild erectile dysfunction , though the study size is small (50 men).
According to Examine.com, the standard dose for maca is 1500 – 3000 mg.
Horny Goat Weed – 50mg: this herb has been used as the traditional remedy in China for centuries to aid erectile dysfunction, fatigue, pain other conditions.
In recent years Horny Goat Weed is touted to be the natural alternative to the blue pills. Similar to the active ingredient of blue pills, Icariin (the active ingredients of Horny Goat Weed) helps to inhibit an enzyme called PDE5. As PDE5 restrict blood flow to the penis, inhibiting PDE5 enhance erection. However, Icariin is not as effective as the blue pills .
In addition, this herb helps to boost testosteron – but only in rats. 
Use of Horny Goat Weed is possibly safe for most people, though few may experience upset stomach and dry mouth.
Yohimbe Bark Extract – 5omg: also known as Yohimbine, it’s commonly found in sexual enhancement supplements. Many believe it’s a natural remedy for erectile dysfunction, though studies show mixed results.
According to Wikipedia, the therapeutic index for Yohimbine is quite low, and dose should not exceed 100 mg. Each serving of Staminol contains 50 mg of Yohimbe Bark Extract, so it’s considered safe.
Note that Yohimbe bark is on the FDA list of dangerous supplements. It has been associated with these side effects: skin flushing, dizziness, headaches, nervousness, stomach upset, frequent urination, painful urination, elevated heart rate and blood pressure. You will want to approach the herb with caution.
As well, Anyone with kidney, liver, heart or psychiatric problems should avoid Yohimbe.
DHEA – 25mg: DHEA is a hormone produced by your body’s adrenal glands. Depending on the body’s needs, it can convert into testosterone or estrogen.
For the purpose of testosterone enhancement, the recommended dose is 100 mg for a person over 40. If you are under 40, you shouldn’t take DHEA without your doctor’s supervision. 
Note 1: DHEA may not be an approved substance in athletic competition.
Note 2: If your T levels are in the normal range, raising them higher may not improve erection issues.
Fenuegreek seed extract – 600 mg : Fenugreek is an annual native plant in Arab region and India. Historically, it was used as to enhance libido, improve digestive problems and to induce child birth.
Most related research 500-600 mg of Fenugreek extract.
Because of these demonstrated benefits, you will find Ginkgo in many male virility supplements. However, the evidence is lacking to support the use of Ginkgo for sexual health improvement.
One pilot study found that Ginkgo Biloba supplementation is shown to improve libido in patients who suffer from antidepressant-induced sexual dysfunction. And, Ginkgo appeared to benefit female subjects to a larger degree than male subjects. 
Pros of Staminol
#1. It’s endorsed by Dr. Frank Costa, an urological surgeon and member of GNC medical advisory board.
#2. The product comes with 30-day money back guarantee.
#3. The formula contains beneficial ingredients in therapeutic dose.
Cons of Staminol
#1. It contains Yohimbe Bark Extract, which may result in unpleasant side effects in some men.
#2. There’s no clinical study to back up the claims made by the manufacturer. It’s unclear if Staminol formula has been tested for safety and effectiveness.
#3. There are mixed reviews on this product.
One big concern with GNC
The products sold by GNC may not be properly labeled.
It’s reported that GNC, Target, Walmart and Wal Greens have been selling were allegedly selling store brand herbal supplements that either didn’t contain the labeled substance or contain ingredients that weren’t listed on the labels. 
As well, Vitalikor, a product promoted and sold for sexual enhancement in GNC stores, was found to contain hidden drug ingredient .
To be fair, GNC Staminol is not outrageously expensive ($36.99 for 6o capsules according to the official GNC website). At that price, Staminol is worth experimenting with, though the ingredient profile is on the weak side.
I still think this doctor approved formula is the best male enhancement solution available on the market, anecdotally speaking. It contains the essential nutrients to empower your penis. You may notice a slight temporary increase in girth, but the real magic is that it boosts erection quality and delay orgasm. It’s also the only clinically proven product. Now you can try it for 60 days.
All that said, if you plan to try Staminol, or any other supplements, be sure to keep your doctor in the loop!