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Natural and Highly Versatile 24-Hour TEST Stack

  • Build Lean Muscle Mass, Strength, Hardness
  • Enhance Workout Performance
  • Suppress Estrogen Levels
  • Boost Natural Growth Factors
  • Increase Libido
  • Promote Restful Sleep

Daytime and Nighttime Natural Testosterone Stack Formulated to Support a Variety of Men's Health and Fitness Goals

FLEX Stack® ADVANCED is a dual-supporting natural testosterone stack designed to constantly supply the system with non-stop 24-hour testosterone support, which can then help facilitate healthy muscle growth, enhance daily health and wellness, and support numerous men's health goals.*

Powered by N-TEST 600® ADVANCED, a healthy and natural free testosterone booster that contains the clinically-studied ingredient Testofen® to increase free testosterone levels by up to 98%, FLEX Stack® ADVANCED maximizes your physiological levels of testosterone to help support greater muscle strength and size, elevate fitness activity and performance, and enhance overall daily wellness.*

Phase 2 of FLEX Stack ADVANCED is Z-TEST®, a nighttime anabolic catalyst that supports natural testosterone levels, blocks estrogen, increases natural growth factors (GH), and promotes a more restful, restorative sleep.* When these two formulas are used in tandem and have the ability to reinforce each other's results, they create a stronger more suitable environment to drive advanced results.*

Natural Daytime Free Testosterone Booster

N-TEST 600® ADVANCED is a strong natural testosterone booster fully loaded with 600 mg of Testofen®, the clinically studied and proven amount necessary to support and increase healthy free testosterone levels up to 98%. This is especially significant because only 2% of testosterone is unbound, or bioavailable and “free” to enter cells and exert its biological actions of binding to androgen receptors. Because N-TEST 600® ADVANCED offers testosterone support naturally versus synthetically, it provides all the positive men’s health and muscle-building results without the negative androgenic and estrogen-related side effects.*

Key Lean Muscle Building Ingredients:

N-TEST 600® ADVANCED includes 10 mg of elemental Boron, 350 mg of Tribulus terrestris, and is reinforced with 150 mg of Smilax officinalis and 100 mg of Black Maca Root Powder. This superior formulation helps to build up healthy testosterone levels and synergistically support increases in strength, size, lean muscle mass and hardness. N-TEST 600® ADVANCED is an ideal choice to help you begin you’re your path toward optimizing your daily health, living an active lifestyle, and reaching your fitness goals.*

Estrogen-Suppression Agent:

N-TEST 600® ADVANCED is loaded with 100 mg of Diindolymethane (DIM), which is designed to block the estrogen receptors activity and interferring with them to help raise the ratio of testosterone to estrogen. With DIM causing more testosterone to be freed, the results can help support a stronger capacity to build muscle from workouts, a higher sex drive, better moods and improved health.*

Strong Bioavailability:

Delivered via liquid gels, N-TEST 600® ADVANCED features BioPerine® for advanced uptake and increased absorption of the ingredients necessary to achieve results. It enhances the formula's overall capability of being absorbed and utilized by the body toward producing stronger results.*


Versatile Nighttime Anabolic Catalyst

Use Z-TEST® in conjunction with any testosterone supplement to fully support and increase anabolic gains. Z-TEST® can also be used alone as a PCT (Post Cycle Therapy) after an intense on-cycle, specifically optimizing healthy testosterone levels during the night-time while also restoring your endocrine system back to its natural homeostasis.*

Anti-Aromatase/Estrogen Blocker:

Z-TEST’s formulation helps block estrogen, which helps to avoid the negative and adverse androgenic and estrogen-related side effects commonly associated with natural or artificial sources of testosterone supplementation.*

Boosts Natural Growth Factor:

Z-TEST® supports the release of more natural growth factor, which the body produces less of with age. Z-TEST® uses these growth factors to increase muscle hypertrophy, support lean body definition, and improve recovery.*

Restful Sleep:

Z-TEST’s formulation also includes ingredients used to promote a more relaxing, restful & restorative sleep to aid recovery.*

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Boron is an essential trace mineral that naturally occurs in certain nuts, fruits, and vegetables, and is known to help decrease and regulate estrogen. As a result of reducing estrogen levels, testosterone levels remain high and become more available to help support desired goals.*


An extract of fenugreek seed containing the steroidal saponins, sapogenins and furostanol saponins, which have been suggested in human studies to raise free testosterone (the biologically active form) and act as important precursors for the synthesis of a number of sex hormones for an increased libido.† Just as important, not only does Testofen® boost free testosterone, but it also aids in fat loss. Participants in a study have significantly raised testosterone, and also didn't gain any weight. Blood Urea nitrogen levels were also significantly reduced after consumption of Testofen®, which shows a reduction in protein catabolism.*

Testofen®, unlike other Fenugreek products available today, contains high concentrations of a specific group of saponin glycosides isolated and characterized exclusively by Gencor scientists. These compounds, called fenusides, are the subjects of ongoing research, which Gencor believes will continue to support Fenugreek's testosterone-promoting benefits. Testofen® is a registered trademark of Gencor Pacific, Inc.

†Effect of Testofen® on safety, anabolic activity and factors affecting exercise physiology. ©Copyright 2008 by Gencor Nutrients, Inc.

Tribulus terrestris:

Bulgarian herb that tends to increase both free and total testosterone levels, and as a result enhances your muscle building capabilities and sex drive. It is believed that it exerts its effects through an increase in Luteninizing hormone (LH) levels, a hormone that signals the body to increase its testosterone production.

Smilax officinalis

Smilax, otherwise known as Sarsparilla, the tropical plant found in Mexico, doesn’t add testosterone to your system directly, but instead it does help to trigger and signal other hormones to activate in the body. Due to this response, Smilax is believed to help support and stimulate testosterone-like effects that can lead to anabolic strength, energy, and muscle-building results.*

Black Maca Root Powder

Sourced from the Andes Mountains in Peru, Black Maca is loaded with amino acids, minerals, vitamins and antioxidants. With such a strong nutritional profile it’s very deserving of its status as a powerful ‘superfood’. Black Maca has a wide range of supportive health benefits, notably its long-standing tradition of helping to enhance energy, build up stamina, and improve athletic performance. And its benefits have also been linked toward helping with libido and arousing sexual desire.*

Diindolylmethane (DIM)

Diindolylmethane (DIM) blocks the estrogen receptors activity, and by interferring with them, it helps raise the ratio of testosterone to estrogen. With DIM causing more testosterone to be freed, this means a result in a higher sex drive, better moods, lean muscle building, and bone-strengthening from workouts. Other possible DIM benefits include the fat burning and the increase of insulin sensitivity, which can help with the uptake of nutrients overall.*


BioPerine®, a black pepper fruit extract, is the only product sourced out of piperine to obtain a patented status for its ability to increase the bioavailability of nutritional compounds. Secondly, it is the only source from piperine to have undergone clinical studies in the U.S. to substantiate its safety and efficacy for nutritional use.


Indole-3-carbinol occurs naturally in cruciferous vegetables such as broccoli, cabbage, cauliflower, brussels sprouts, collard greens and kale. With powerful antioxidant protection, I3C helps to prevent cellular damage caused by free radicals. In addition I3C can help reduce estrogen levels while maintaining a healthy hormonal balance. I3C is also known to support the liver's detoxification processes as well as normal cellular reproduction.*


Believed to be an effective aromatase inhibitor, Chrysin supports decreasing your body’s level of estrogen. It has also been shown to induce an anti-inflammatory effect.*


As a precursor to dopamine, a chemical in the brain that is linked to cravings and pleasure, L-Dopa is used to maintain elevated dopamine levels, helping you to resist the urge to overeat at night. L-Dopa may also be used to trigger production of human growth hormone, which in turn builds muscle and reduces fat.*


Produced by the pineal gland from the amino acid Tryptophan, melatonin helps the body know when it’s time to sleep or when it’s time to wake up. It maintains the Circadian Rhythm of our body, which is the built-in 24-Hour “clock” inside our body. The Circadian Rhythm plays an important role when we should wake up and when we should fall asleep, and melatonin is directly linked. When your surrounding is dark, the body produces more melatonin, and when your surrounding is bright, melatonin is reduced. By increasing melatonin production in the evening, Z-TEST® will help make it easier to fall asleep.*


Used to help relieve stress by inducing a relaxing effect without drowsiness, L-Theanine helps reduce mental and physical stress, improves focus and concentration, and enhances mood. Studies show it helps both reduce the time that it takes a person to fall asleep as well as decrease the number of nighttime awakenings due to its relaxing and tranquilizing properties.*

5-Hydroxytryptophan (5-HTP):

A naturally-occurring amino acid and chemical precursor as well as metabolic intermediate in the biosynthesis of the neurotransmitters serotonin and melatonin from tryptophan. 5-HTP is used as an antidepressant, appetite suppressant, and sleep aid.

Ingredients & Supplemental Facts Label

Ingredients and Supplemental Facts Label

Level 1: Beginner

Anabolic Switch:

Use N-TEST 600® ADVANCED for 2 weeks, then follow with Z-TEST® for 2 weeks. Repeat this process for 8 full weeks.

Advantage: Switching on and off between both products provides a more constant and steady supply of healthy testosterone needed to achieve and sustain muscular gains over the course of 8 weeks. It also allows the body to maintain a more natural state of homeostasis, to help avoid adverse androgenic/estrogen-related side effects.*

Level 2: Intermediate

Anabolic Shift:

Use N-TEST 600® ADVANCED alone for 4 full weeks, then follow up with Z-TEST® for 4 weeks.

Advantage: Flood your system with an onslaught of testosterone to maximize full anabolic results in a short time frame. Following with Z-TEST® to improve recovery, and to also restore your body’s natural testosterone back to normal levels. This staggered, dual attack TEST approach provides the positive anabolic muscle gains without the estrogen-related side effects.*

Level 3: Hardcore

Anabolic Mayhem:

Use N-TEST 600® ADVANCED and Z-TEST® together daily for 4 intense weeks.

Advantage: Overload your system with a relentless and constant 24-hour barrage of muscle-yielding testosterone to build more muscle, spike performance, and maximize anabolic results. This aggressive approach creates an environment of anabolic mayhem that takes a hold of your system quickly, to produce extreme results in an accelerated amount of time.*


N-TEST 600® ADVANCED: KEEP OUT OF REACH OF CHILDREN. Consult with your physician before using this product. Do not take this product if you have a medical condition including, but not limited to, diabetes, heart disease, psychological disorder, prostate hypertrophy or hormonal abnormalities. Consult with your physician if you are taking antidepressants, MAO inhibitors, or other prescription drugs. This product should not be used by pregnant or lactating women. Not intended for use by persons under the age of 18. Do not exceed recommended dose. Do not use if tamper resistant seal is broken. STORE IN A COOL, DRY PLACE, AND AVOID EXCESSIVE HEAT.

Z-TEST®: KEEP OUT OF REACH OF CHILDREN. Do not exceed recommended dose. Not intended for use by persons under the age of 18. For adult use only at bedtime. This product is not to be taken by pregnant or lactating women. This product is not intended for use by those with a serious medical condition. Consult your physician prior to use if you are taking OTC, prescription medication (including but not limited to MOA Inhibitors), or other dietary supplements. Do not use in conjunction with alcoholic beverages, when driving a vehicle, or while operating machinery. Do not use if tamper resistant seal is broken. STORE IN A COOL, DRY PLACE. AVOID EXCESSIVE HEAT.

California Residents  |  WARNING: Cancer and Reproductive Harm – www.P65Warnings.ca.gov/Food

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*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease.