The Science Behind Premium Testosterone Support

Q: Can I take it with training?

Yes. It is designed for active men and is taken daily, whether you train that day or not. Several of the ingredients, including shilajit, ashwagandha and zinc, were studied specifically in resistance-trained or recreationally active populations.

Formula Snapshot

A transparent look at the ingredients and forms used in Premium Testosterone Support

Every active disclosed by name, dose, and standardization — no proprietary blends, no hidden math.

Ingredient	Amount	Form / Standardization	Primary Purpose
TestoSurge®	500 mg	Standardized fenugreek extract · ≥ 20% furostanolic saponins	Supports free & total testosterone
Ashwagandha	600 mg	KSM-66® root extract · ≥ 5% withanolides (HPLC)	Stress resilience & cortisol regulation
Shilajit	500 mg	Purified Himalayan resin · fulvic acid ≥ 50%	Supports testosterone & DHEAS
Vitamin D3	2,000 IU	Cholecalciferol	Hormonal & endocrine support
Chelated Zinc	15 mg	Zinc bisglycinate chelate	Cofactor in testosterone biosynthesis

Research At A Glance

A quick overview of the evidence behind each ingredient

Five actives. The signal, the evidence type, and the primary focus — at a glance. Select any card to jump to its full clinical review.

Strong

TestoSurge®

RCTs + meta-analysis · Total & free testosterone

Read the research → Strong

Ashwagandha

Multiple RCTs · Stress resilience + hormonal support

Read the research → Strong

Shilajit

Human clinical trials · Testosterone + DHEAS

Read the research → Moderate–Strong

Vitamin D3

Systematic reviews · Hormonal support

Read the research → Moderate

Chelated Zinc

Mechanistic research + reviews · Testosterone biosynthesis

Read the research →

Key Research Findings

What the literature consistently shows

Plain-language summaries of the strongest, most replicated findings across the formula.

01

Fenugreek supplementation has demonstrated support for total and free testosterone in multiple human studies and a pooled meta-analysis.⁴

02

Ashwagandha has demonstrated support for testosterone, DHEA-S, LH and cortisol regulation in randomized clinical research.¹⁰

03

Shilajit has shown support for total testosterone, free testosterone and DHEAS in a placebo-controlled human trial over 90 days.¹⁵

04

Vitamin D status is strongly associated with healthy testosterone status, with repletion most beneficial in deficient men.²⁰

05

Zinc plays an essential role in testosterone biosynthesis and male reproductive function.²⁴

Who It's For

Who Premium Testosterone Support is designed for

Built for active men who want a transparent, research-backed approach to hormonal support — not a marketing-led test booster.

Men over 30 Men looking to support healthy testosterone levels Men who want better vitality and drive Men focused on strength and performance Men who value evidence-based ingredients Men who prefer transparent formulas over proprietary blends

Beyond Boosting

Testosterone support is more than a single number

Healthy androgen output is the downstream signal of six upstream systems. Move those, and the number moves with them.

Stress

Chronic cortisol elevation suppresses the HPG axis.

Sleep

Most daily testosterone release occurs during deep sleep.

Nutrition

Energy availability and dietary fat shape steroidogenesis.

Recovery

Training without recovery flattens the anabolic response.

Body Composition

Visceral fat increases aromatase activity.

Micronutrients

Zinc, magnesium and vitamin D status set the ceiling.

How the Formula Works

Four mechanisms, one clean stack

01

Support endogenous pathways

Nutrient and botanical inputs that act upstream of natural steroidogenesis — not exogenous hormones.

02

Support stress resilience

Adaptogenic load on the HPA axis to keep cortisol from suppressing androgen output.

03

Support androgen availability

Mechanisms studied for free vs. bound testosterone, including SHBG-related pathways.

04

Correct common gaps

Replete the micronutrients (D3, Zn) where insufficiency is most prevalent in active adults.

Methodology

How we evaluated the research

A consistent evidence hierarchy. The same standard applied to every ingredient before it earns a place in the formula.

Human clinical trials prioritized

Evidence in humans is weighted above all in-vitro or animal data.

RCTs prioritized

Randomized, placebo-controlled trials anchor each ingredient claim.

Meta-analyses & systematic reviews

Pooled evidence shapes our view of effect size and consistency.

Mechanistic studies as context

Used to explain how an ingredient works — never as the only proof.

Animal vs. human evidence

Animal data is clearly distinguished and never treated as definitive.

Dose & form transparency

We require studied doses and the same standardized forms used in trials.

Ingredient Deep Dives

Each active, on the record

Overview, mechanism, research highlights, and quality standard — for every ingredient in the formula.

Ingredient · 01

TestoSurge®

Standardized fenugreek seed extract (Trigonella foenum-graecum)

Overview

TestoSurge® is a patented fenugreek extract from Indus Biotech, standardized for furostanolic saponins — the constituents associated with the hormonal endpoints reported in clinical work on fenugreek.²

Mechanism

Investigated for inhibition of aromatase and 5α-reductase activity, with downstream effects on the free-to-bound testosterone ratio rather than total production alone. Protodioscin content may also support luteinizing hormone (LH) secretion.

Research highlights

Randomized, placebo-controlled trials in resistance-trained males have reported improvements in total and bioavailable testosterone and body composition over 8-week protocols.³ A 2020 meta-analysis pooling four RCTs found a statistically significant increase in total serum testosterone,⁴ and a 2021 systematic review of 32 RCTs identified fenugreek as one of only two herbs with positive effects on testosterone in men.⁷

Quality standards

Standardized to ≥ 20% furostanolic saponins. HPLC identity verified.

Research callout

Studied at 500 mg/day in resistance-trained adults.

Reviewed by the 4 Gauge research team

Ingredient · 02

Ashwagandha

KSM-66® Withania somnifera root extract

Overview

A full-spectrum, root-only ashwagandha extract standardized to ≥ 5% withanolides by HPLC — a more rigorous standardization than UV-based testing. Withanolides are the steroidal lactones responsible for ashwagandha's hormonal and adaptogenic effects.⁸

Mechanism

Modulates the HPA axis. By dampening cortisol output under chronic stress, it relieves a known suppressor of GnRH and downstream testosterone synthesis, while also supporting LH.⁹

Research highlights

A crossover RCT in aging men reported an 18% greater increase in DHEA-S and a 14.7% greater increase in testosterone vs. placebo,¹⁰ and a 12-week RCT showed significant increases in free testosterone and LH.¹¹ Reviews report cortisol reductions of roughly 11–32% alongside favorable testosterone effects in men.¹³

Quality standards

Standardized to ≥ 5% withanolides by HPLC.

Research callout

Strongest evidence base of any adaptogen for stress-driven hormonal endpoints.

Reviewed by the 4 Gauge research team

Ingredient · 03

Shilajit

Purified Himalayan resin

Overview

A mineral-rich resin from high-altitude rock strata, characterized for its fulvic and humic acid content. 4 Gauge uses shilajit standardized to ≥ 50% fulvic acid by HPLC.¹⁴

Mechanism

The fulvic-acid fraction acts as a mineral-shuttling carrier; mechanistic work points to activation of steroidogenic enzymes (3β-HSD and 17β-HSD) and reduced testicular oxidative stress.¹⁸

Research highlights

A 90-day randomized, double-blind, placebo-controlled trial in healthy men (250 mg twice daily) reported significant increases in total testosterone, free testosterone and DHEAS, with LH and FSH maintained.¹⁵ An 8-week RCT also showed shilajit attenuated fatigue-induced losses in muscular strength.¹⁶

Quality standards

Purified resin, fulvic acid ≥ 50%, screened for heavy metals.

Research callout

Use purified resin only — raw shilajit can carry heavy-metal contamination.

Reviewed by the 4 Gauge research team

Ingredient · 04

Vitamin D3

Cholecalciferol

Overview

Vitamin D functions as a steroid-hormone precursor. Its receptor (VDR) is expressed throughout reproductive tissues, including the Leydig cells of the testes.¹⁹

Mechanism

Adequate 25(OH)D status supports normal expression of steroidogenic enzymes and may lower SHBG, increasing free testosterone; insufficiency consistently tracks with lower androgen markers.²²

Research highlights

A PRISMA systematic review found vitamin D deficiency is associated with lower testosterone and that supplementation may improve it, particularly in deficient men,²⁰ a finding supported by a 2024 meta-analytic review of androgen endpoints.²¹

Quality standards

Cholecalciferol form, assayed for potency.

Research callout

Test 25(OH)D. Aim for sufficiency, not megadosing.

Reviewed by the 4 Gauge research team

Ingredient · 05

Chelated Zinc

Zinc bisglycinate

Overview

Zinc is a cofactor for over 300 enzymes, including those involved in testosterone biosynthesis. Bisglycinate is selected for tolerability and absorption.²⁴

Mechanism

A required cofactor in androgen production that also inhibits aromatase and supports LH-receptor signalling on Leydig cells. Restricting dietary zinc lowers testosterone in young men within weeks.²⁵

Research highlights

Reviews and clinical work show zinc status is directly linked to serum and seminal testosterone, with repletion most beneficial in deficient or heavily-training men.²⁶²⁷

Quality standards

Zinc bisglycinate chelate, verified identity and potency.

Research callout

Athletes lose zinc through sweat — repletion matters most under high training load.

Reviewed by the 4 Gauge research team

Quality Standard

Generic testing vs. HPLC verification

Most of the category still uses UV testing because it's cheaper. We use HPLC because it identifies — and quantifies — the actual compound you paid for.

Comparison	Generic Testing Industry baseline	4 Gauge · HPLC Pharmaceutical standard
Potency verification	Estimated by UV absorbance — bulk reading only.	Quantified per active compound on every batch.
Consistency	Lot-to-lot variance often unmeasured.	Standardized profile verified against reference chromatogram.
Specificity	Cannot distinguish actives from look-alike compounds.	Separates and identifies individual constituents.
Standardization	Marker compound declared, rarely confirmed.	Standardization confirmed analytically before release.
Quality control	Pass/fail at minimum thresholds.	Pharmaceutical-grade method used as the release standard.

Research Summary

The formula at a glance

Ingredient	Dose	Evidence	Primary endpoint	Strength
TestoSurge®	500 mg	RCTs + meta-analysis	Free testosterone, body comp.	Moderate–High
Ashwagandha	600 mg	Meta-analysis + RCTs	Cortisol, recovery, total T	High
Shilajit	500 mg	RCT	Total + free testosterone	Moderate
Vitamin D3	2,000 IU	Systematic reviews	Androgen status (if deficient)	Moderate
Zinc bisglycinate	15 mg	Reviews + mechanistic	Testosterone in deficiency	Moderate

Continue Your Research

Go deeper on each ingredient

Dedicated research briefs for every active in the formula — and the guides that put them in context.

Research Brief

Fenugreek Research

Mechanism, dose-response and clinical endpoints for fenugreek extracts.

Coming soon

Research Brief

Ashwagandha Research

RCTs and meta-analyses on KSM-66® and standardized withanolides.

Coming soon

Research Brief

Shilajit Research

Clinical trials on purified resin, fulvic acid and DHEAS endpoints.

Coming soon

Research Brief

Vitamin D & Testosterone

How 25(OH)D status maps to androgen output in men.

Coming soon

Research Brief

Zinc & Testosterone

Cofactor biology and repletion evidence in active adults.

Coming soon

Guide

Ingredients Guide

How 4 Gauge selects, doses and verifies every active.

Read guide →

Put it into practice

Ready to put the research into practice?

A transparent formula built on premium, evidence-based ingredients — standardized actives at clinically studied doses, manufactured with quality in mind from sourcing through release.

Transparent formula
Premium ingredients
Made without proprietary blends
45-day guarantee

Shop Premium Testosterone Support See what's inside

4 Gauge Premium Testosterone Support bottle next to research-backed formula callout

About the Author

Who wrote and reviewed this page

Author & Reviewer

Connor Southworth

Founder, 4 Gauge

Connor Southworth is the founder of 4 Gauge and has spent years researching, formulating, and manufacturing premium nutritional supplements. He personally oversees product development and ingredient selection, with a focus on evidence-based formulations designed to support performance, recovery, and long-term health.

10+ yrsIn nutrition

Evidence-ledFocus

June 2026Last reviewed

June 2027Next review

FAQ

Honest answers, no fine-print games

Is this a testosterone replacement?

No. Premium Testosterone Support is not testosterone replacement therapy (TRT) and contains no exogenous hormones. It supplies nutrients and standardized botanical extracts studied for their ability to support your body's own natural testosterone production and hormonal balance. If you have a diagnosed hormone condition, speak with a qualified clinician.

How is 4 Gauge different from a generic test booster?

Every active is disclosed by name, dose and standardization — no proprietary blends. The botanical ingredients are HPLC-verified for identity and potency, and the doses reflect the amounts used in human clinical research rather than under-dosed 'pixie-dusting'.

How long until I notice anything?

The clinical studies behind these ingredients typically ran 8–12 weeks, with some hormonal endpoints measured over 90 days. Consistent daily use for at least 8 weeks — alongside good sleep, training and nutrition — gives the formula the best chance to work.

Can I take it with training?

Yes. It's designed for active men and is taken daily, whether you train that day or not. Several of the ingredients — shilajit, ashwagandha and zinc — were studied specifically in resistance-trained or recreationally active populations.

Is it third-party tested?

Yes. The key botanical actives are verified by HPLC for identity and potency, and shilajit is screened for heavy metals to recognised limits before release.

Sources & References

The literature behind the formula

Grouped by topic. Human RCTs, meta-analyses and systematic reviews are weighted above mechanistic or animal data.

01 · TopicBackground & Declining Testosterone

1.Maćkowski M, et al. "The Role of Environmental Factors, Lifestyle, and Supplementation in Regulating Endogenous Testosterone Levels in Men." IJITSS, 2025. View source

02 · TopicTestoSurge® / Fenugreek Research

2.Campbell B, et al. "The effects of a commercially available botanical supplement on strength, body composition, power output, and hormonal profiles in resistance-trained males." J Int Soc Sports Nutr, 2010. PMC2978122
3.Poole C, et al. "Effects of TESTOSURGE supplementation on strength, body composition and hormonal profiles during 8 weeks of resistance training." J Int Soc Sports Nutr, 2009. PMC3313155
4.Mansoori A, et al. "Effect of fenugreek extract supplement on testosterone levels in male: A meta-analysis." Phytother Res, 2020. doi:10.1002/ptr.6627
5.Albaker WI. "Fenugreek and Its Effects on Muscle Performance: A Systematic Review." J Pers Med, 2023. PMC10054907
6.Drevon CA, et al. "Effect of a plant extract of fenugreek on testosterone: a double-blind RCT." PLoS ONE, 2024. PMC11407615
7.Lopresti AL, et al. "Examining the Effects of Herbs on Testosterone Concentrations in Men: A Systematic Review." Adv Nutr, 2021. PMC8166567

03 · TopicAshwagandha Clinical Studies

8.Zakrzewska N, et al. "The Multifaceted Effects of Ashwagandha Root Extract on Physical Performance, Cognitive Function, Mental Health, and Safety in Adults." QS, 2024. View source
9.Mieszkowska JW, et al. "The Neuroendocrinology of Chronic Stress: Evaluating the Clinical Efficacy of Ashwagandha on Serum Cortisol." IJITSS, 2026. View source
10.Lopresti AL, Drummond PD, Smith SJ. "A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha in Aging, Overweight Males." Am J Mens Health, 2019. PMC6438434
11.Smith SJ, Lopresti AL, Fairchild T. "Efficacy and Safety of Witholytin® Ashwagandha Root Extract: a randomized, double-blind, placebo-controlled trial." J Psychopharmacol, 2023. PMC10647917
12.Prajapati P, et al. "A Randomized Double-blind Study on Ashwagandha Root Powder Ghan (AF-43): stress, anxiety, sleep and anabolic hormonal outcomes." IJRA, 2025. doi:10.4103/IJRA.IJRA_4_26
13.Gómez Afonso A, et al. "Effects of Withania somnifera on Hematological and Biochemical Markers, Hormonal Behavior, and Oxidant Response in Healthy Adults: A Systematic Review." Curr Nutr Rep, 2023. PMC10444651

04 · TopicShilajit Clinical Studies

14.Syed G, et al. "Study of Fulvic Acid: A Natural Dietary Supplement." 2014. View source
15.Pandit S, et al. "Clinical evaluation of purified Shilajit on testosterone levels in healthy volunteers." Andrologia, 2016. doi:10.1111/and.12482
16.Keller JL, et al. "The effects of Shilajit supplementation on fatigue-induced decreases in muscular strength and serum hydroxyproline levels." J Int Soc Sports Nutr, 2019. PMC6364418
17.Das A, et al. "The Human Skeletal Muscle Transcriptome in Response to Oral Shilajit Supplementation." J Med Food, 2016. PMC4948208
18.Yadav A, et al. "Shilajit mitigates chemotherapeutic drug-induced testicular toxicity: steroidogenesis modulation and Nrf-2/Keap-1 signaling." J Ayurveda Integr Med, 2024. PMC11362644

05 · TopicVitamin D & Testosterone Research

19.Heijboer AC, et al. "Effects of vitamin D supplementation on androgens in men with low testosterone levels: a randomized controlled trial." Eur J Nutr, 2019. PMC6842386
20.Saxena A, et al. "Association Between Vitamin D Deficiency and Testosterone Levels in Adult Males: A Systematic Review." Cureus, 2023. PMC10518189
21.Alharran A, et al. "The Impact of Vitamin D on Androgens and Anabolic Steroids among Adult Males: A Meta-Analytic Review." Diseases, 2024. PMC11506788
22.Giovannucci E, et al. "Association between plasma 25-OH vitamin D and testosterone levels in men." Clin Endocrinol, 2012. PMC3712348
23.Krysiak R, et al. "Vitamin D Status Determines Cardiometabolic Effects of Testosterone Replacement Therapy in Men with Late-Onset Hypogonadism." Nutrients, 2025. PMC11944846

06 · TopicZinc & Testosterone Research

24.Cortés-Barberena E, et al. "Zinc and Its Impact on the Function of the Testicle and Epididymis." Int J Mol Sci, 2024. PMC11354358
25.Memon AR, et al. "Molecular basis for the effects of zinc deficiency on spermatogenesis." Indian J Urol, 2015. PMC4300574
26.Chaudhari AR, Kothari R. "Zinc Levels in Seminal Fluid in Infertile Males and its Relation with Serum Free Testosterone." J Clin Diagn Res, 2016. PMC4948382
27.Colagar AH, Fallah A, Mohammad-Hasani A. "Zinc is an Essential Element for Male Fertility." Crescent J Med Biol Sci, 2018. PMC6010824