7 Day Customer Support
  • Live Chat
  • 1-800-537-9910
iSatori Isa-Test GF


An Product
Targets the 3 Most Important Hormones for Increased Muscle!*
Muscle & Strength Rewards

Earn 2 points for every dollar you spend at Muscle & Strength! Spend your points on order discounts, fitness gear and exclusive products.

2 Free Samples

Try before you buy! You can choose 2 free samples with every order you place at Muscle & Strength.

Same Day Shipping

We ship fast! USA orders placed before 6pm EST will be shipped the same day.

International orders placed before 4pm EST will be shipped the same day.

60 Day Guarantee

Not happy with your purchase? No problem. Simply return it to us within 60 days and we'll replace it, credit your account, or give you a full refund.

Contact Us

If you have any questions about products please call us on 1-800-537-9910 or email support@muscleandstrength.com

Buying Options
$32.99 49.9900
120 Bio-Diffusion Capsules
30 Servings | $1.10 Per Serving
Out of Stock
Nutrition Info

120 Bio-Diffusion Capsules

Serving Size: 4 Capsules
Servings Per Container: 30
Amount Per Serving
Vitamin C (as Ascorbic Acid)
Vitamin B6 (Pyridoxine HCl)
Magnesium (as Oxide & Aspartate)
Zinc (as Zinc Aspartate)
Isa-Test™, a Proprietary Blend Containing:
Tribulus Extract, (Tribulus Terrestris L.) (aerial parts), (60% total saponins, 20% Protodioscin), Epimedium Extract, (Epimedium sagittatum and Epimedium brevicornum)(leaf), (standardized for 10% icariin), P-450 Estrogen Inhibitor Citrus bioflavanoid complex, (Citrus sinesis) (peel & fruit), (50% hesperidin), Tongkat Ali Extract 20:1, (Eurycoma longifolia)(root), Ajuga turkestanica extract 10:1 (stem and leaf), Grape seed extract, (Vitis vinifera L.) (seed) , (standardized for 95% proanthocyanidins), Fenugreek Extract, Fenugreek Extract (trigonella foenum-graecum L.) (seed), (standardized for 50% fenuside saponins), Rhaponticum carthamoides extract (root), (standardized for 5% Ecdysterones)
SOMATRIN™, a Proprietary Blend Containing:
Velvet bean extract, (Mucuna Pruriens) (Seed), Nettle extract 30:1, (urtica dioica)(root), (standardized for 20% L-Dopa), Melatonin, (N-Acetyl-5-Methoxytryptamine)
ISAWFLOW™, a Proprietary Blend Containing:
Butchers Broom Extract, (ruscus aculeatus)(root) (standardized for 20% sterolic heterosides), Hesperidin Methyl Chalcone, (citrus sinensis)(fruit)(90% hesperidin)
* % Daily Value is based on a 2,000 calorie diet. Your daily values may be higher or lower based on your calorie needs.
† Daily Value (DV) not established.
Gelatin, Magnesium Stearate, Silicon Dioxide, Microcrystalline Cellulose, Titanium Dioxide, Fd&C Red #40, Fd&C Blue #1, Fd&C Red #28

As a dietary supplement, men take 4 capsules with a full glass of water one hour prior to exercise. On non-training days, take 4 capsules one hour prior to bedtime. Take with or without food. FOR BEST RESULTS, use continuously for a minimum of 8 weeks.

Use only as directed. Do not exceed suggested daily dose. Not intended for individuals under the age of 18, unless instructed by a doctor. Women should not use this supplement; so obviously, do not use this product if you are pregnant, nursing, or are contemplating pregnancy. If you have a medical condition or are taking any prescription medications, please consult your physician first. WARNING: For adult use only at bedtime. This product is not to be taken by pregnant or lactating women. If you are taking medication or have a medical condition, consult a physician before using this product. Do not use in conjunction with alcoholic beverages, when driving a vehicle, or while operating machinery.

Expand Info
Product Information
Swipe left/right to reveal product information

Natural Testosterone Stimulation

Testosterone, estrogen, and growth factors are the most potent anabolic hormones for increased muscle mass and strength gains! Here's why ISA-TEST GF is the breakthrough testosterone formula you've been waiting for:*

  • Increase Your Bioavailable Testosterone!*
  • Exclusive P-450™ Reduces "Female-Hormone" Estrogen!*
  • Spikes Anabolic Growth Factors!*
  • Rapid Bio-Diffusion Delivery Technology

Testosterone, Estrogen, and Growth Factors

ISA-TEST GF works from the first dose to dramatically raise your testosterone levels, naturally, whenever you want.*

Every bodybuilder knows these are the three most potent hormones for increased muscle mass, strength gains, and cranked up sexual drive. ISA-TEST GF is now the world's only formula proven to manipulate all three... for total anabolic growth!*

Even more impressive, here are five undisputed facts that are sure to convince you of the power of Isa-Test GF:

FACT 1: ISA-TEST contains clinical data revealing an INCREASE in BIO-AVAILABLE TESTOSTERONE...*

FACT 2: ISA-TEST contains the scientifically shown P-450™ TO REDUCE the "female-hormone" ESTROGEN...*

FACT 3:ISA-TEST is the FIRST EVER to use the GH breakthrough SOMATRIN™ to INCREASE YOUR STRENGTH on the FIRST workout...*

FACT 4:ISA-TEST will not shut down your body's natural production of Testosterone, like prohormones and illegal steroids...*

FACT 5: ISA-TEST contains Rapid Bio-Diffusion Delivery™ Technology, so you can "feel" its effects from THE VERY FIRST DOSE!*

ISA-TEST GF Ingredient Breakdown


Somatrin is a unique and powerful compound, found in ISA-TEST GF, which possesses serious anabolic growth factor supporting properties. In fact, in a recent clinical study, Somatrin was suggested to increase human growth hormone factors when taken 30 minutes before training.*

Testofen™ (Trigonella Foenum Greacum)

Testofen is a not-so-well-known herb but it's become quite an underground sensation for many European bodybuilders. It contains a variety of powerful anabolic compounds, among them Protodioscin and Steroidal Saponins.*

Unlike other natural testosterone-boosting herbs, Testofen contains a host of active compounds in addition to Protodioscin and Saponins—all suggested to promote Testosterone (or T, for short) levels, muscle mass, and libido.*

Research suggests the majority of these saponins exist as saponin glycosides. Fenuside is a set of saponin glycosides unique to Testofen that have been specially extracted and standardized to yield the highest strength and purity for maximal benefit.

Now, since Testofen is the only natural substance that produces these unique Fenusides, what's interesting is Testofen "acts" more like Testosterone by binding to the Testosterone receptor sites.*

Equally important, though, it has been suggested to do this without shutting off the body's own natural production of T. In a recent randomized, placebo-controlled clinical trial with 60 men, Testofen supported increased Testosterone in test subjects.*

It's for these reasons, Testofen is one of bodybuilding's best-kept secrets because, as suggested by multiple research studies, it may support androgenic and anabolic properties to increase muscle mass.*

Tribulus Terrestris

This herbal extract, otherwise known as Tribulus or by the active compounds saponins and protodioscin, was originally discovered and researched in Bulgaria (the home of many of today's Olympic Powerlifters). Even though it's been lopped into the same boat as prohormones, it's absolutely, positively not a hormone. In fact, tribulus works with your body—not to inhibit it—but to help support its natural ability to produce T and help maintain levels already within normal range.*

Eurycoma Longifolia (Longjax™)

Animal studies have suggested effects of Eurycoma longifolia on increases in T. Currently, there have been no negative side effects reported from the use of Eurycoma.*

Zinc/Magnesium (Zinc Aspartate, Magnesium Aspartate)

Supported by two studies, this combination of minerals has suggested its worth in the lab and in the real world.*

It's become apparent for some time now that consistent resistance training causes a depletion of vital minerals in the muscle cells. One such critical mineral is zinc. Zinc has also been suggested to play an important role in the body's ability to get a restful night's sleep. When you are able to get a sound night's sleep, your body releases many more hormones, namely T and growth hormone—two very powerful anabolic hormones for building muscle mass. In fact, a larger percentage of T secreted daily in men occurs during sleep, and levels peak during the early morning. As you can see, a good night's sleep is vitally important for increasing T levels, and thus supplementing with zinc may help replace not only the "depleted" zinc from weight training but supply the body with adequate amounts for a restful night's sleep.*

What's more, zinc and magnesium supplementation have both been suggested to reduce levels of the catabolic "stress" hormone.*

Because zinc and magnesium deficiencies are both commonly found in the general public and are even more prevalent in intensely trained athletes and weight trainers, this combination has become popular. I suppose it's also safe to say that because zinc and magnesium is merely a harmless mineral combination, it's becoming more and more widely used by competitive athletes, including college, professional, and Olympian. And with great success!*


Ajuga is a traditional folk remedy used in Central Asia for thousands of years to support muscular strength and physical endurance under harsh, exhausting conditions.*


Rhaponticum is a plant that grows throughout eastern Siberia. Currently, rhaponticum is listed in the Russian Pharmacopoeia as a supporting compound for increasing work efficiency under stressful conditions, improving athletic performance, and promoting recovery after intense muscular workloads.*


Also known as "horny goat weed," epimedium is grown as an ornamental herb in Asia and the Mediterranean region. It has been used for centuries to treat fatigue.*

P-450™ Hesperetin

Hesperetin ([(S)-2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4- methoxyphenyl)-4-H-1-benzopy-ran-4-one]) is an interesting citrus bio-flavonoid found primarily in oranges and lemons. The antioxidant properties of hesperetin are fairly well established.*

Grapeseed Extract

An extract from red grapes containing the active compounds known as oligomeric proanthocyanidins (OPC). OPC have been suggested to exhibit antioxidant and cardio-supporting properties.*

Rapid Bio-Diffusion Delivery™ Technology

With the guidance of a leading specialist and medical doctor, iSatori Technologies developed an exclusive Rapid Bio-Diffusion Delivery™ technology, which uses a sophisticated "micro-particlization" process, so Isa-Test starts working from the very first dose to crank up the body's natural testosterone production, fast.*

ISA-TEST GF Frequently Asked Questions

What is Isa-Test, and how does it work?

Isa-Test is a precise combination of natural ingredients clinically shown to cause rapid increases in Testosterone and a reduction in the "female-hormone" estrogen. It's designed to promote explosive gains in strength, increased muscle mass, and improved sexual drive and performance.*

What is the difference between the "old" Isa-Test and the new Isa-Test?

Isa-Test is now the only testosterone stimulator that also increases growth hormone factors, because our researchers at iSatori discovered and added the new proven compound, Somatrin™. In addition, it's formulated with our exclusive Rapid Bio-Diffusion Delivery™ technology for 200% faster absorption and increased potency.*

What is the new compound in Isa-Test, Somatrin™?

Somatrin™ is a unique and powerful compound, found only in ISA-TEST, which possesses serious anabolic growth factor stimulating properties. In fact, in a recent clinical study, Somatrin was shown to increase human growth hormone factors. A widely known scientific fact, growth hormone is the primary anabolic hormone responsible for accelerated muscular growth.*

How does Isa-Test's Rapid Bio-Diffusion Delivery system work?

With the guidance of a leading pharmaceutical specialist and medical doctor, iSatori Technologies developed an exclusive Rapid Bio-Diffusion Delivery™ technology, which uses a sophisticated "micro-particlization" process, so Isa-Test starts working from the very first dose to crank up the body's natural testosterone production, fast. Within 30 minutes of taking Isa-Test, you'll begin to "feel" it going to work… an instant rush of testosterone… because of its lightening-fast absorption and increased potency. No other testosterone formula in existence contains this state-of-the-art delivery technology. You can find it only in Isa-Test.*

What does the research say about Isa-Test, and is it safe?

The efficacy of Isa-Test's incredible testosterone-enhancing and estrogen-reducing effects were scientifically documented by researchers Rob Mendel, PhD, and Dr. Tim Ziegenfuss of the Ohio Research Group of Exercise Science and Sports Nutrition! The conclusion of the study was after just three weeks (and Isa-Test works on a progressive basis), Free or usable Testosterone levels increased and estrogen levels decreased. Equally important, all of the subjects' health markers (e.g., liver, kidney, cholesterol, blood pressure, etc.) were normal and healthy. So, we know, without a reason of a doubt, Isa-Test works impressively fast and is completely safe.*

How can I take Isa-Test for maximum results?

Take a full dose (four capsules) of Isa-Test 60 minutes before weight training. On non-training days, take one full dose before bedtime to optimize the restorative effects of Testosterone while sleeping. For increased testosterone production, a more advanced "dosing strategy," devised by our scientific team, can be found inside The Testosterone Solution.

Do I need to "load" or "cycle" Isa-Test?

"Loading" or "cycling" is not necessary. And because Isa-Test is natural and won't shut down your body's own production of testosterone, you don't need to cycle it and can use it for as long you would like. It is, however, always a good idea to take a break for one to two weeks, after using any kind of supplement after 12 weeks.

How much Testosterone increase do you need to boost muscle growth?

Given the vast number of factors involved in muscle growth (e.g., training status/stimulus, genetics, diet, etc.), this question is a bit too broad in scope to answer definitively. However, one possibility is that a situation similar to nutrient timing (for carbs and protein) exists with Testosterone. In other words, by elevating Testosterone during certain key periods, muscle growth, strength, etc., can be accelerated. This idea underpins the "dosing strategy" of Isa-Test.

Why is it so important for men to suppress Estrogen?

While Estrogen does have important functional roles in men (such as maintaining bone and cardiovascular health), in excess, Estrogen can promote water retention, increase bodyfat, and cause gynecomastia; that is, the female-like increase in breast tissue. This is particularly true in men who are already overweight and/or have elevated blood sugar levels. Some research even indicates increasing levels of environmentally produced, synthetic Estrogens (called xenoEstrogens) have the potential to disrupt the delicate endocrine system in men, potentially reducing sperm counts and increasing the risk of testicular cancer. The goal with Isa-Test is to keep Estrogen at levels that optimize health and body composition.

What kind of results can I expect from using Isa-Test?

Within the first two to four weeks, expect to see increases in strength and improvements in sexual performance. Within eight weeks of continuous use, expect your body composition to change dramatically (e.g., more muscle, less fat).*

Are there other supplements I should take to enhance the benefits of Isa-Test?

Although Isa-Test has been designed as a standalone supplement, there are three other supplements you can take to magnify its health benefits. First and foremost is a high-quality multivitamin with added antioxidants. Second, protein—about 20 or 30 grams before and after training. And third, creatine—ideally taken within minutes after each training session.*

Is it possible to duplicate the effects of Isa-Test by purchasing each of the individual ingredients?

No—every ingredient in Isa-Test undergoes an exclusive extraction and manufacturing process to enhance its potency and purity. Also, the patent-pending Rapid Bio-Diffusion Delivery™ Technology ensures the delivery (bioavailability) of the ingredients in Isa-Test is unmatched.*


  1. Ang, H.H., and Lee, K.L., "Effect of Eurycoma longifolia Jack on Orientation Activities in Middle-Aged Male Rats," Fundam Clin Pharmacol 16.6 (2002) : 479-83.
  2. Ang, H.H., Sim M.K., "Eurycoma longifolia Jack Enhances Libido in Sexually Experienced Male Rats," Exp Anim 46.4 (1997) : 287-90.
  3. Annewieke, W., "Measures of Bioavailable Serum Testosterone and Estradiol and Their Relationships with Muscle Strength, Bone Density, and Body Composition in Elderly Men," J Clin Endocrinol Metab 85 (2000) : 3276-82.
  4. Awoniyi, C., et al., "Regulation of Gonadotrophin Secretion in the Male: Effect of an Aromatization Inhibitor in Estradiol-Implanted, Orchidectomized Dogs," Journal Andriol 7 (1986) : 239-43.
  5. Bamman, M.M., et al., "Urban Mechanical Load Increases Muscle IGF-1 and Androgen Receptor mRNA Concentrations in Humans," Am J Physiol 280 (2001) : E383-90.
  6. Bhasin, S., et al., "Androgen Effects on Body C Growth Horm IGF," Res 13 Suppl A (2003) : S63-71.
  7. Bhasin, S., et al., "The Effects of Supraphysiologic Doses of Testosterone on Muscle Size and Strength in Normal Men," N Engl J Med 335.1 (1996) : 1-7.
  8. Bhasin, S., "Effects of Testosterone Administration on Fat Distribution, Insulin Sensitivity, and Atherosclerosis Progression," Clin Infect Dis 37 Suppl 2 (2003) : S142-9.
  9. Brown, G.A., et al., "Effects of Anabolic Precursors on Serum Testosterone Concentrations and Adaptations to Resistance Training in Young Men," Int J Sport Nutr Exerc Metab 10.3 (2000) : 340-59.
  10. Department of Obstetrics and Gynecology, National University Hospital, National University of Singapore, Singapore.
  11. Exercise Biochemistry Laboratory, Department of Health and Human Performance, Iowa State University, Ames, IA 50011, USA.
  12. Ferrando, A.A., et al., "Testosterone Injection Stimulates Net Protein Synthesis but Not Tissue Amino Acid Transport," Am J Physiol 275.5 Pt 1 (1998) : E864-71.
  13. Gauthaman, K., et al., "Aphrodisiac Properties of Tribulus Terrestris Extract (Protodioscin) in Normal and Castrated Rats," Life Sci 71.12 (2002) : 1385-96.
  14. Guay, A.T., et al., "Clomiphene Increases Free Testosterone Levels in Men with Both Secondary Hypogonadism and Erectile Dysfunction: Who Does and Does Not Benefit?" Int J Impot Res 15.3 (2003) : 156-65.
  15. Human Performance Specialists, Inc. Thomas Incledon, President, "6-OXO on Endocrine Responses in Resistance-Trained Men," Abstract presented at The American Dietetic Association Annual Meeting in October 2003.
  16. Juniewicz, P.E., et al., "Aromatase Inhibition in the Dog. Effect on Serum LH, Serum Testosterone Concentrations and Spermatogenesis," Journal Urology 139.4 (1988) : 827-31.
  17. Kadi, F.P., et al., "The Expression of Androgen Receptors in Human Neck and Limb Muscles: Effects of Training and Self-Administration of Androgenic-Anabolic Steroids," Histochemistry and Cell Biology 113 (2000) : 25-29.
  18. Kraemer, W.J., et al., "Endogenous Anabolic Hormonal and Growth Factor Responses to Heavy Resistance Exercise in Males and Females," Int J Sport Med 12 (1991) : 228-235.
  19. Kraemer, W.J., et al., "Hormonal and Growth Factor Responses to Heavy Resistance Exercise Protocols," J Appl Physiol 69 (1990) : 1442-50.
  20. Manni, A., et al., "Bioavailability of Albumin-Bound Testosterone," J Clin Endocrinol Metab 61.4 (1985) : 705-10.
  21. McCell, G.E., et al., "Acute and Chronic Hormonal Responses to Resistance Training Designed to Promote Muscular Hypertrophy," Can J Appl Physiol 24 (1999) : 96-107.
  22. Meeking, DR, et al., Exercise-induced GH secretion is enhanced by the oral ingestion of melatonin in healthy adult male subjects, Eur J Endocrinol. 1999 Jul;141(1):22-6.
  23. Pardridge, W.M., "Serum Bioavailability of Sex Steroid Hormones," Clin Endocrinol Metab 15.2 (1986) : 259-78. Review.
  24. Phillips, S.M., et al., "Mixed Muscle Protein Synthesis and Breakdown After Resistance Exercise in Humans," Am J Physiol 273 (1997) : E99-107.
  25. Protich, M., et al., "Clinical Trial of a Tribestan Preparation in Infertile Men" [Article in Bulgarian], Akush Ginekol (Sofiia) 22.4 (1983) : 326-9.
  26. R. Mendel, PhD, et al. "Hormonal Responses to ISA-TEST Admin.," Ohio Research Group. [2005].
  27. Sinha-Hikim, I., et al., "Testosterone-Induced Muscle Hypertrophy Is Associated with an Increase in Satellite Cell Number in Healthy, Young Men," Am J Physiol Endocrinol Metab 285.1 (2003) : E197-205.
  28. Snyder, P.J., et al., "Effects of Testosterone Replacement in Hypogonadal Men," J Clin Endocrinol Metab 85.8 (2000) : 2670-7.
  29. Spaliviero, J.A., et al., "Luteinizing Hormone Receptor-Mediated Effects on Initiation of Spermatogenesis in Gonadotrophin-Deficient (hpg) Mice Are Replicated by Testosterone," Biol Reprod 2003 Sep 3 [Epub ahead of print].
Overall Rating
4.8 out of 5 stars
Reviews (10)
Verified Buyers (9)
Review Graph
  • 5 star

  • 4 star

  • 3 star

  • 2 star

  • 1 star

Overall Rating
    Show More +
    Show Less -
User Image
Build Muscle
I have been taking this for about 2 weeks now in conjunction with a pre-workout. My strength has greatly improved and I feel less tired after workouts which is probably also due to the pre-workout. I have noticed that I do have a shorter temper when driving and I get annoyed easier but it isn't that often that it affects my life negatively. I kind of liked how test freak improved my libido a lot more than this, however I feel stronger from isa test GF. Good stuff!*
Was this helpful?
You found this not helpful
3 of 3 found this helpful
2011-05-25 18:28:26Z
Overall Rating
    Show More +
    Show Less -
User Image
Verified Buyer
Is the first time when I use and is the best for grow testosterone*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2020-08-31 17:27:43Z
Overall Rating
    Show More +
    Show Less -
User Image
Antonio W
Verified Buyer
Amazing product and great Price*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2020-02-29 21:32:12Z
Overall Rating
    Show More +
    Show Less -
User Image
Jani L
Verified Buyer
Best testobooster in the market.*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2019-12-12 12:16:52Z
Overall Rating
    Show More +
    Show Less -
User Image
Sean K
Verified Buyer
Great product but 2 tabs before training is more than enough & 1-2 on non training days for recovery. Same with creatine just 1 scoop before workout. Never exceed with supplements less is more. ISA test is very strong so plenty of minerals throughout gym session, take about 45 mins before so u can get the best results out of the supplement I will buy again. Be aware ur sex drive will be through the roof when taking.*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2019-07-24 10:55:39Z
Overall Rating
    Show More +
    Show Less -
User Image
Tony R
Burn Fat
Verified Buyer
Haven't had a good chance to put this to the test with a decent weight program.*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2018-08-06 17:44:25Z
Overall Rating
    Show More +
    Show Less -
User Image
Ibrahim A
Verified Buyer
still didnt use, recommended by a friend*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2018-01-02 06:52:05Z
Overall Rating
    Show More +
    Show Less -
User Image
Deanna R
Verified Buyer
I really love this product great stuff*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2016-12-17 14:28:36Z
Overall Rating
    Show More +
    Show Less -
User Image
Verified Buyer
I would recommend this product to others. I definitely can tell a difference.*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2016-03-12 19:57:16Z
Overall Rating
    Show More +
    Show Less -
User Image
Sports Improvement
Verified Buyer
Great product*
Was this helpful?
You found this not helpful
0 of 0 found this helpful
2015-10-05 00:16:25Z
* Muscle & Strength does not imply any medical claims from this review. There are no guarantees of specific results and results may vary.
* These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.