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HTLT G-Test was created based on the 3 main ingredients found in our more simple 3-Test that have been made popular by some of the top scientists that have heavily researched the testosterone boosting category. G-Test is carefully researched, utilizing ingredients mostly backed by human studies. Learn more about our formula below!

Supplement Facts

Ingredients

Tongkat Ali Extract

Tongkat Ali is a well-known herb native to Southeast Asia, known for its therapeutic effects on sexual and hormonal health. Tongkat Ali contains a variety of bioactive compounds, including eurycomanones, glycosaponins, and polysaccharides, which have been shown to support increased sex drive, testosterone production, and improve sperm parameters in men [3].

A meta analysis done in 2021 by Lazarus et al evaluating 7 human trials found a positive net change in total testosterone levels with Tongkat Ali supplementation compared to placebo, in both hypo & eugonadal men.

Lazarev, A., & Bezuglov, E. (2021). Testosterone Boosters Intake in Athletes: Current Evidence and Further Directions. Endocrines, 2(2), 109-120. https://doi.org/10.3390/endocrines2020011

Testosterone Boosters Intake in Athletes: Current Evidence and Further Directions

Effect	Study 1: A decrease of cortisol by 16%, and an increase of testosterone by +37% was noted in healthy adults. Study 2: a significant increase in testosterone (from 8.0 ± 1.6 ng/mL). Free testosterone also increased significantly (from 9.4 ± 3.3 to 12.6 ± 5.9 pg/mL).
Trial Design	Systematic Review: two RCTs on Tongkat Ali in healthy populations
Trial Length	Study 1: 4 weeks Study 2: 2 weeks
Number of Subjects	Study 1: 63 Study 2: 32
Population	Study 1: Men and Women with moderate stress levels Study 2: Healthy men aged 24.4 ± 4.7 years
Dosage	Study 1: 200 mg/day of Physta™ Tongkat Ali Extract Study 2: 600mg/day Tongkat Ali extract

Endocrines | Free Full-Text | Testosterone Boosters Intake in Athletes: Current Evidence and Further Directions. (n.d.). Retrieved March 18, 2022, from https://www.mdpi.com/2673-396X/2/2/11

How Does Tongkat Ali Work?

Tongkat Ali extract works through a variety of mechanisms to support sexual and hormonal function. It is hypothesized that Tongkat’s active ingredients work as a 17α-hydroxylase activator, an aromatase inhibitor and demonstrates PDE5 inhibition to a notable degree [4,3].

By possible upregulation of 17α-hydroxylase, Tongkat Ali can increase the production of the sex hormones: pregnenolone, 17-OH-pregnenolone, DHEA, progesterone, 17-OH-progesterone, and 4-androstenedione [4]. This results in increased total testosterone & neurosteroid levels; on the other hand, by inhibiting the aromatase enzyme & enzymatic production of cortisol, Tongkat Ali can promote increases in total/free testosterone [1,2,3].

Ashwagandha Extract (Sensoril)

Ashwagandha is an Ayurvedic herb historically used as an adaptogen. It can significantly increase testosterone levels in males and is thought to do so by downregulation of cortisol. The systematic review below provides an overview of the effects of this herb on male sex hormones and its safety profile.

Examining the Effects of Herbs on Testosterone Concentrations in Men: A Systematic Review: Ashwagandha

Effect	Three of the 4 studies demonstrated positive effects of ashwagandha supplementation on testosterone concentrations in men. One study using KSM-66® was associated with a significant increase in testosterone concentrations (17.3% increase) after 90 d compared with the placebo group (3.8% increase) (P < 0.01). Another study showed that the ashwagandha group significantly increased testosterone concentrations (11.4%) compared with baseline values (P = 0.038)
Trial Design	Systematic Review; Three studies used a randomized, double-blind, placebo-controlled study design and 1 study used a randomized, double-blind, placebo-controlled, crossover study design
Trial Length	~8 wks
Number of Subjects	4 studies
Population	A total of 197 male participants were recruited for the studies, with ages ranging from 18 to 70 y and sample sizes ranging from 46 to 60 participants.
Dosage	Two studies used a patented ashwagandha root extract, KSM-66®, manufactured by Ixoreal (using a water-based extraction process, standardized to 5% withanolides) (35, 62), and the other 2 studies used another patented root and leaf extract, Shoden®, manufactured by Arjuna Natural (using a 70:30 ethanol:water extraction process, standardized to 35% withanolide glycosides). KSM study dosage: 600-675mg daily. Shoden® study dosage: 21 mg of withanolide glycosides daily

Smith, S., Lopresti, A., Teo, S., & Fairchild, T. (2020). Examining the Effects of Herbs on Testosterone Concentrations in Men: A Systematic Review. Advances in Nutrition, 12. https://doi.org/10.1093/advances/nmaa134

D-Chiro Inositol

D-Chiro Inositol is a cyclic sugar alcohol with biological activity as a second-messenger in the insulin signalling cascade, possessing anti-hyperglycemic and aromatase inhibiting properties, it has been shown to positively affect testosterone levels in males [6,7]. In a pilot trial on 10 healthy males, oral administration of D-chiro-inositol administration at 1g/day was associated with reduced serum levels of estrone (- 85.0%) and estradiol (- 14.4%), and increased serum levels of testosterone (+ 23.4%) and dehydroepiandrosterone (DHEA) (+ 13.8%) [7]. Additionally, epiandrosterone levels were higher (+39%) after treatment [7].

Fig. 1 Effect of D-chiro-inositol (DCI) treatment on total testosterone (T) levels. Total serum T levels from 10 male volunteers at baseline (t0) and after 30 days of treatment (t1) with 1 g DCI per day are presented as: a median values of total T (box plots). The boxes denote the interquartile range between the first and third quartiles (25th and 75th percentiles, respectively), the whiskers represent the minimum and maximum values, and the line inside the boxes represents the median value (p = 0.0020; Wilcoxon signed rank sum test);[7]

Fig. 4 Effect of D-chiro-inositol (DCI) treatment on estrone (E1) levels. E1 levels from 10 male volunteers at baseline (t0) and after 30 days of treatment (t1) with 1 g DCI per day are presented as: a median values of E1 (box plots) (p = 0.0020; Wilcoxon signed rank sum test) [7]

Fenugreek Extract

Fenugreek is a spice which has an extensive use in food preparation and more recently sports supplementation, a recent meta analysis by Isenmann et al conducted a quantitative analysis on 6 human trials evaluating the effects of fenugreek preparations on sex hormones and athletic markers in healthy individuals; a statistically significant improvement was noted in total testosterone levels, free testosterone levels, and reductions of estradiol, stating that “chronic application of fenugreek has performance-enhancing and anabolic effects in male athletes” [19].

NAC (N-Acetyl-Cysteine) & Selenium

In a randomized double blind placebo controlled trial published in The Journal of Urology by Safarinejad et al, it was found that administration of NAC (600mg/daily) and Selenium (200mcg/daily) in combination led to a significant increase in serum testosterone levels and improvement of sperm parameters in infertile men [20].

The exact mechanism is unknown, the authors state: “A prominent hypothesis is that decreased antioxidant function may be a contributing factor (of hypogonadism).”, indicating that the improvements in testicular function may be attributed to a reduction of oxidative stress affecting the leydig and sertoli cells of the testes [20].

Boron

Boron is a trace mineral found in coffee, dairy, fruits and vegetables. Supplementation with boron has been shown to increase free testosterone levels in males, primarily through its effects on the metabolism of sex hormones and SHBG [8,9].

Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines

Effect	Resulted in a statistically significant increase in the level of free testosterone, from 11.8 pg/mL to 15.2 pg/mL
Trial Design	Non-randomized controlled trial
Trial Length	1 week
Number of Subjects	8
Population	Young males between the ages of 18-29 years old
Dosage	10 mg daily

Naghii, M. R., Mofid, M., Asgari, A. R., Hedayati, M., & Daneshpour, M.-S. (2011). Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. Journal of Trace Elements in Medicine and Biology: Organ of the Society for Minerals and Trace Elements (GMS), 25(1), 54–58. https://doi.org/10.1016/j.jtemb.2010.10.001

Shilajit Extract (std. 50% Fulvic Acid, generic)

Shilajit is an ingredient derived from decomposed organic plant material and minerals, characterized by its richness in fulvic acid amongst other organic compounds [23].

It has a long history of use in South and East Asia for increasing vitality [23].

Trials evaluating Shilajit’s effects on males’ testosterone levels are promising, in which the greatest response was seen in hypogonadal men, seeing a +23.5% improvement in total testosterone levels [21].

In another human trial, Shilajit administration was also shown to significantly increase total testosterone, free testosterone and DHEA-S levels in healthy volunteers compared to placebo [22].

Wild Yam Extract (std. for Diosgenin)

Wild yam extract contains a significant amount of Diosgenin, a steroidal saponin which has been studied in humans as being a beneficial natural compound for improving athletic performance and increasing sex hormone levels in healthy males [18]. In a randomized placebo controlled trial, Diosgenin supplementation combined with resistance training increased serum DHEA, serum DHT, serum free testosterone, increased 1-rep max on the deadlift and increased arm fat-free mass compared to placebo [18].

Horii, N., Hasegawa, N., Fujie, S., Iemitsu, K., Uchida, M., Hamaoka, T., & Iemitsu, M. (2020). Effects of Dioscorea esculenta intake with resistance training on muscle hypertrophy and strength in sprint athletes. Journal of Clinical Biochemistry and Nutrition, 67(3), 338–343. https://doi.org/10.3164/jcbn.19-124

Zinc Citrate

Zinc deficiency can be a cause of low testosterone levels in men, zinc supplementation has been shown to reliably increase testosterone production in zinc-deficient men and is a first line intervention when trying to naturally increase testosterone levels in the context of nutrient deficiency [10,11].

Zinc status and serum testosterone levels of healthy adults

Effect	Zinc supplementation of marginally zinc-deficient normal elderly men for six months resulted in an increase in serum testosterone from 8.3 +/- 6.3 to 16.0 +/- 4.4 nmol/L (p = 0.02).
Trial Design	Comparative Study
Trial Length	6 Months
Number of Subjects	40 men
Population	20 to 80 y of age
Dosage	459 mumol (30mg) of elemental zinc (administered as zinc gluconate) per day

As, P., Cs, M., Fw, B., Jw, H., & Gj, B. (1996). Zinc status and serum testosterone levels of healthy adults. Nutrition (Burbank, Los Angeles County, Calif.), 12(5). https://doi.org/10.1016/s0899-9007(96)80058-x

P5P (Pyridoxal phosphate, active form of vitamin B6)

The active form of vitamin B6, P5P, has been shown to improve outcomes in the context of hyperprolactinemia, a possible endocrine cause of hormonal suppression (excess prolactin secretion results in secondary hypogonadism) [12,13,14]. Although the trials evaluating Vitamin B6/P5P’s effects on hyperprolactinemia used a very high dosage (300mg q12h PO), we felt a lower dose was warranted as the degree of hyperprolactinemia experienced by the participants in this trial was pharmacologically induced (secondary to antipsychotic use), above and excess of what might exist in individuals who do not have prolactinomas or concurrent use of antipsychotics. The dosage we used was less than the studied dosage with intent to target a favorable safety profile (some individuals can experience peripheral neuropathy with very high doses of vitamin B6).

Vitamian B6 (P5P): Safety and Efficacy of High-Dose Vitamin B6 as an Adjunctive Treatment for Antipsychotic-Induced Hyperprolactinemia in Male Patients With Treatment-Resistant Schizophrenia

Effect	Vitamin B6 supplementation led to an average of a 68.1% reduction in serum prolactin levels.
Trial Design	Randomized double-blinded controlled study
Trial Length	16 weeks
Number of Subjects	200
Population	Patients with Treatment-Resistant-Schizophrenia, adult males between 20 and 40 years of age.
Dosage	300 mg/12 h

Zhuo, C., Xu, Y., Wang, H., Fang, T., Chen, J., Zhou, C., Li, Q., Liu, J., Xu, S., Yao, C., Yang, W., Yang, A., Li, B., Chen, Y., Tian, H., & Lin, C. (2021). Safety and Efficacy of High-Dose Vitamin B6 as an Adjunctive Treatment for Antipsychotic-Induced Hyperprolactinemia in Male Patients With Treatment-Resistant Schizophrenia. Frontiers in Psychiatry, 12.

Vitamin D3

Vitamin D3 deficiency is a common global health issue which exists primarily in higher latitudes where individuals may not get adequate sunlight exposure throughout the year, some forms of secondary hypogonadism have a strong association with vitamin D deficiency [16]. Correcting deficient vitamin D levels is a safe and effective way to promote optimal health outcomes, especially in the context of deficiency. G Test+ implements a dosage in line with the RDA for vitamin D3 as a conservative approach, to reduce the risk of hypervitaminosis D for those who already consume a daily vitamin D supplement or plan to take this perpetually (fat-soluble vitamins can accumulate in tissues if taken in excess for long durations and can lead to toxicity if levels become too high).

Effect of vitamin D supplementation on testosterone levels in men

Effect	Vitamin D supplementation led to significant increases in total testosterone levels (from 10.7±3.9 nmol/l to 13.4±4.7 nmol/l; p<0.001), bioactive testosterone (from 5.21±1.87 nmol/l to 6.25±2.01 nmol/l; p=0.001), and free testosterone levels (from 0.222±0.080 nmol/l to 0.267±0.087 nmol/l; p=0.001). The placebo group did not experience any significant changes in testosterone measures.
Trial Design	Randomized Control Trial
Trial Length	12 months
Number of Subjects	54
Population	Men (age range not specified, greater than 20+ years old)
Dosage	3,332 IU/day

Pilz, S., Frisch, S., Koertke, H., Kuhn, J., Dreier, J., Obermayer-Pietsch, B., Wehr, E., & Zittermann, A. (2011). Effect of Vitamin D Supplementation on Testosterone Levels in Men. Hormone and Metabolic Research, 43(3), 223–225. https://doi.org/10.1055/s-0030-1269854

Research

Chan, K. Q., Stewart, C., Chester, N., Hamzah, S. H., & Yusof, A. (2021). The effect of Eurycoma Longifolia on the regulation of reproductive hormones in young males. Andrologia, 53(4). https://doi.org/10.1111/and.14001
Leisegang, K., Finelli, R., Sikka, S. C., & Selvam, M. K. P. (2022). Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials. Medicina, 58(8). https://doi.org/10.3390/medicina58081047
Rehman, S. U., Choe, K., & Yoo, H. H. (2016). Review on a Traditional Herbal Medicine, Eurycoma longifolia Jack (Tongkat Ali): Its Traditional Uses, Chemistry, Evidence-Based Pharmacology and Toxicology. Molecules, 21(3), Article 3. https://doi.org/10.3390/molecules21030331
Eng, A. (2007). Correcting systemic androgen levels using Eurycoma longifolia (United States Patent No. US20070009621A1). https://patents.google.com/patent/US20070009621A1/en
Chinnappan, S. M., George, A., Pandey, P., Narke, G., & Choudhary, Y. K. (2021). Effect of Eurycoma longifolia standardised aqueous root extract-Physta® on testosterone levels and quality of life in ageing male subjects: a randomised, double-blind, placebo-controlled multicentre study. Food & nutrition research, 65, 10.29219/fnr.v65.5647. https://doi.org/10.29219/fnr.v65.5647
Montt-Guevara, M. M., Finiguerra, M., Marzi, I., Fidecicchi, T., Ferrari, A., Genazzani, A. D., & Simoncini, T. (2021). D-Chiro-Inositol regulates insulin signaling in human adipocytes. Frontiers in Endocrinology, 12, Article 660815. https://doi.org/10.3389/fendo.2021.660815
Monastra, G., Vazquez-Levin, M., Bezerra Espinola, M.S. et al. D-chiro-inositol, an aromatase down-modulator, increases androgens and reduces estrogens in male volunteers: a pilot study. Basic Clin. Androl. 31, 13 (2021). https://doi.org/10.1186/s12610-021-00131-x
Naghii, M. R., Mofid, M., Asgari, A. R., Hedayati, M., & Daneshpour, M.-S. (2011). Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. Journal of Trace Elements in Medicine and Biology: Organ of the Society for Minerals and Trace Elements (GMS), 25(1), 54–58. https://doi.org/10.1016/j.jtemb.2010.10.001

Pizzorno L. Nothing Boring About Boron. Integr Med (Encinitas). 2015 Aug;14(4):35-48. PMID: 26770156; PMCID: PMC4712861.
Khan, S. S., Carter, R. E., & Greenland, P. (2023). Association of anemia with cardiovascular disease: A cohort study. The American Journal of Medicine. Advance online publication. https://doi.org/10.1016/j.amjmed.2023.01.045
As, P., Cs, M., Fw, B., Jw, H., & Gj, B. (1996). Zinc status and serum testosterone levels of healthy adults. Nutrition (Burbank, Los Angeles County, Calif.), 12(5). https://doi.org/10.1016/s0899-9007(96)80058-x
Zhuo, C., Xu, Y., Wang, H., Fang, T., Chen, J., Zhou, C., Li, Q., Liu, J., Xu, S., Yao, C., Yang, W., Yang, A., Li, B., Chen, Y., Tian, H., & Lin, C. (2021). Safety and Efficacy of High-Dose Vitamin B6 as an Adjunctive Treatment for Antipsychotic-Induced Hyperprolactinemia in Male Patients With Treatment-Resistant Schizophrenia. Frontiers in Psychiatry, 12.
Witwit, Suha. (2018). The Role of Vitamin B6 in Reducing Serum Prolactin in Comparison to Cabergoline. International Journal of Pharmaceutical Quality Assurance. 10. 10.25258/ijpqa.10.1.17.
Araújo, A. N., Wessling, A., & Bugalho, M. J. (2018). Male hypogonadism – when two endocrine causes merge in the same patient. Endocrine Abstracts, 56, P810. https://doi.org/10.1530/endoabs.56.P810
Janz, T., & Pearson, C. (2013). Vitamin D blood levels of Canadians. Health at a Glance. Statistics Canada Catalogue no. 82-624-X. https://www150.statcan.gc.ca/n1/pub/82-624-x/2013001/article/11727-eng.htm
Lee, D. M., Tajar, A., Pye, S. R., Boonen, S., Vanderschueren, D., Bouillon, R., O'Neill, T. W., Bartfai, G., Casanueva, F. F., Finn, J. D., Forti, G., Giwercman, A., Han, T. S., Huhtaniemi, I. T., Kula, K., Lean, M. E., Pendleton, N., Punab, M., Wu, F. C., & EMAS study group (2012). Association of hypogonadism with vitamin D status: the European Male Ageing Study. European journal of endocrinology, 166(1), 77–85. https://doi.org/10.1530/EJE-11-0743
Pilz, S., Frisch, S., Koertke, H., Kuhn, J., Dreier, J., Obermayer-Pietsch, B., Wehr, E., & Zittermann, A. (2011). Effect of Vitamin D Supplementation on Testosterone Levels in Men. Hormone and Metabolic Research, 43(3), 223–225. https://doi.org/10.1055/s-0030-1269854
Horii, N., Hasegawa, N., Fujie, S., Iemitsu, K., Uchida, M., Hamaoka, T., & Iemitsu, M. (2020). Effects of Dioscorea esculenta intake with resistance training on muscle hypertrophy and strength in sprint athletes. Journal of Clinical Biochemistry and Nutrition, 67(3), 338–343. https://doi.org/10.3164/jcbn.19-124
Isenmann, E., Alisauskas, P., Flenker, U., Schalla, J., & Diel, P. (2023). The Anabolic Effect of Fenugreek: A Systematic Review with Meta-analysis. International journal of sports medicine, 44(10), 692–703. https://doi.org/10.1055/a-2048-5925
Safarinejad, M. R., & Safarinejad, S. (2009). Efficacy of selenium and/or N-acetyl-cysteine for improving semen parameters in infertile men: a double-blind, placebo controlled, randomized study. The Journal of urology, 181(2), 741–751. https://doi.org/10.1016/j.juro.2008.10.015
Biswas, T. K., Pandit, S., Mondal, S., Biswas, S. K., Jana, U., Ghosh, T., Tripathi, P. C., Debnath, P. K., Auddy, R. G., & Auddy, B. (2010). Clinical evaluation of spermatogenic activity of processed Shilajit in oligospermia. Andrologia, 42(1), 48–56. https://doi.org/10.1111/j.1439-0272.2009.00956.x
Pandit, S., Biswas, S., Jana, U., De, R. K., Mukhopadhyay, S. C., & Biswas, T. K. (2016). Clinical evaluation of purified Shilajit on testosterone levels in healthy volunteers. Andrologia, 48(5), 570–575. https://doi.org/10.1111/and.12482
Carrasco-Gallardo, C., Guzmán, L., & Maccioni, R. B. (2012). Shilajit: a natural phytocomplex with potential procognitive activity. International journal of Alzheimer's disease, 2012, 674142. https://doi.org/10.1155/2012/674142

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