Boron for Biohackers: SHBG, Free Testosterone and Self-Experiments
Boron from a biohacking angle: mechanisms, SHBG and testosterone data, boron forms, a clean N-of-1 experiment and the safety limits for elemental boron.
Biohacker verdict in 60 seconds
- What boron is: a trace element from fruit, nuts, legumes and drinking water that feeds into metabolic pathways of steroid hormones, vitamin D, calcium and magnesium. mechanistically plausible
- The strongest human signal: in eight healthy men, SHBG was lower six hours after 10 mg of boron; after one week, free testosterone had risen and estradiol had fallen. early study signal
- The counter-test: with 2.5 mg of boron over seven weeks, neither testosterone nor strength nor lean mass changed in training bodybuilders. currently not supported for performance and muscle growth.
- Who a trial is most interesting for: people with a low-boron diet, marginal magnesium intake or a known, medically assessed hormone profile who want to measure cleanly.
- Who is likely to notice little: people who eat a varied plant-rich diet, have normal hormone values and hope for more strength or muscle.
- Limits: EU upper limit of 10 mg of boron per day from all sources; the BfR proposes at most 0.5 mg per daily dose for supplements. Borax is never swallowed.
- Verdict: boron is an exciting candidate for a well-documented, time-limited N-of-1 experiment – not a testosterone booster and not a baseline supplement.
How to read the evidence tags
Every important claim in this article carries its evidence level right next to it:
- well established – several good human studies or reviews with consistent results
- probable or context-dependent – mostly positive human data, but dependent on baseline status, dose or product
- mechanistically plausible – biologically coherent, derived from cell, animal or metabolic data, not confirmed as an effect in humans
- early study signal – small or short human studies with a positive result, not yet independently confirmed
- anecdotal or N-of-1 – individual observations and self-experiments without a control group
- currently not supported – specifically studied without an effect, or no reliable data
Why boron is biologically interesting
Boron is a small, chemically unusual element. Boric acid forms reversible bonds with molecules carrying neighbouring hydroxyl groups – so-called cis-diol structures. Such structures occur in sugars, nucleotides and some signalling molecules. A recent review sees this as an explanation for why boron turns up in such different systems: mineralisation, vitamin D metabolism, hormone-related biomarkers, antioxidant defence and inflammation (Tuzcu et al., 2026). mechanistically plausible
That breadth is exactly what makes boron interesting for self-optimisers – and hard to test. A substance that nudges many systems a little rarely produces a large effect on a single value. The authors of the same review therefore still consider strict essentiality for humans unproven and call for studies with clear dosing of the boron form, pharmacokinetics and adequately sized groups (Tuzcu et al., 2026).
EFSA classifies boron as non-essential, and the US Institute of Medicine has set no requirement because a clear function in humans is missing (Institute of Medicine, 2001). Dietary boron is absorbed mostly as boric acid at about 90 percent and excreted mainly in urine. Adults in the US took in on average 0.87 to 1.35 milligrams of boron per day – mainly from avocados, nuts, prunes, juices, coffee, milk and beans (Institute of Medicine, 2001). well established as intake data.
Boron, boron glycinate and borax: three different things
All amounts in this article refer to elemental boron, not the weight of the compound. A compound is only partly boron: according to its EU authorisation, calcium fructoborate contains 2.5 to 2.9 percent boron, and 220 milligrams of the compound provide about 6.4 milligrams of boron according to EFSA (Commission Implementing Regulation (EU) 2021/2129; EFSA, 2021).
Borax is disodium tetraborate decahydrate. ECHA lists disodium tetraborate in anhydrous form, as the pentahydrate and as the decahydrate with the harmonised classification Repr. 1B, H360FD: “May damage fertility. May damage the unborn child.” (ECHA, 2010).
| Form | What it is | Human data | EU status |
|---|---|---|---|
| Boric acid | simple boron compound; the form boron takes in the body | a few small studies, form often not stated | listed as a nutrient source for supplements |
| Sodium borate | salt of boric acid | no dedicated efficacy studies found | listed as a nutrient source; never swallow household borax |
| Calcium fructoborate | calcium, fructose and 2.5–2.9 % boron | short, small, mostly industry-linked studies | authorised since 2021 as a novel food for adults |
| Boron glycinate, citrate, aspartate | market names; boron with glycine, citrate or aspartate | no comparative absorption studies found | not listed in Annex II of the supplements directive |
The EU classification follows Annex II of Directive 2002/46/EC in the consolidated version of 6 February 2024, which lists boric acid and sodium borate for boron, and the authorisation of calcium fructoborate. For boron glycinate, boron citrate and boron aspartate: an absorption advantage has not been shown. Because dietary boron is already very well absorbed, a large difference between forms is not expected either. currently not supported as a form advantage.
How boron acts on metabolism
In short: in human studies, boron shifts several levers at once – hormone transport, vitamin D, mineral excretion and inflammatory markers. Exactly how this happens at the molecular level in humans is not resolved.
Steroid hormones and SHBG. SHBG (sex hormone-binding globulin) is a transport protein made in the liver. It binds testosterone and estradiol tightly; another part is loosely attached to albumin, and only a small share circulates free. If SHBG falls, the free share can rise at the same total testosterone. In the study by Naghii et al. (2011), SHBG was lower six hours after 10 mg of boron, and after one week free testosterone had risen and estradiol had fallen; dihydrotestosterone and cortisol were higher. early study signal
Vitamin D. In the same study, vitamin D was higher after one week (Naghii et al., 2011). The Institute of Medicine lists an influence of boron on vitamin D metabolism as a discussed function (Institute of Medicine, 2001). early study signal
Calcium and magnesium. In postmenopausal women after a low-boron diet, 3 mg of boron per day reduced urinary excretion of calcium and magnesium; the effect depended on magnesium intake (Nielsen et al., 1987). A second study found no effect on minerals (Beattie & Peace, 1993). early study signal, context-dependent
Inflammatory signals. Six hours after 10 mg of boron, hsCRP and TNF-α were lower, and after one week the measured inflammatory markers had fallen (Naghii et al., 2011). early study signal
Why responses can differ. The Nielsen data show that the boron effect depended on magnesium status. Someone who already takes in plenty of boron from food and water starts from a different point than someone on a low-boron diet. An effect that becomes visible with marginal intake can disappear with good intake. mechanistically plausible
What human studies actually show
| Study and goal | Amount and form | People and duration | Result and evidence |
|---|---|---|---|
| Naghii et al., 2011 – hormones and inflammation | 10 mg boron per day; form not stated | 8 healthy men; 1 week; no parallel placebo group | SHBG lower after 6 hours; after 7 days free testosterone higher, estradiol lower; early study signal |
| Ferrando & Green, 1993 – strength and hormones | 2.5 mg boron per day | 19 bodybuilders aged 20–27; 7 weeks; placebo-controlled | no effect on testosterone, strength or lean mass; currently not supported |
| Nielsen et al., 1987 – minerals and hormones | 3 mg boron per day after a low-boron diet | 12 postmenopausal women; no parallel control group | less urinary calcium and magnesium loss; estradiol and testosterone higher; early study signal |
| Beattie & Peace, 1993 – bone and hormones | 3 mg boron per day after a low-boron diet | postmenopausal women; no parallel control group | no change in minerals, hormones or bone resorption markers; contradicts Nielsen |
| Pietrzkowski et al., 2014 – knee discomfort | 220 mg calcium fructoborate per day (about 6.4 mg boron) | 60 people with knee discomfort; 14 days; placebo-controlled | better discomfort scores; industry-linked, this compound only; early study signal |
SHBG, free testosterone and estradiol
The signal is real – and small in scope. The Naghii study underlies almost every claim about boron and SHBG. It shows a rapid shift in SHBG and, one week later, a hormone profile with more free testosterone and less estradiol. That is exactly the pattern biohackers look for. early study signal
What the study cannot settle: eight participants, one week, no parallel placebo group, no independent replication (PubMed and Europe PMC, as of 14 September 2026) and only laboratory values instead of strength, libido or well-being. Whether the effect persists over weeks, whether it occurs at a lower dose and who shows it has not been studied.
Strength, muscle mass and performance
The only placebo-controlled study in training men found no difference with 2.5 mg of boron over seven weeks in total or free testosterone, lean mass, squat or bench press maximum; both groups got stronger through training (Ferrando & Green, 1993). currently not supported For progress in the gym, training planning, progression and recovery remain the effective levers – for example with a structured progression as in the 5/3/1 article.
Women and menopause
In postmenopausal women, estradiol and testosterone rose under 3 mg of boron, especially with low magnesium intake (Nielsen et al., 1987); a second study found no change (Beattie & Peace, 1993). early study signal, contradictory. The results of the men’s study cannot be applied to women, and we found no human study for perimenopause or libido. A rise in estradiol is not automatically an advantage; hormonal symptoms belong with a doctor.
Joints, bone and inflammation
For the specific compound calcium fructoborate, a placebo-controlled study reports better scores for knee discomfort after 14 days (Pietrzkowski et al., 2014). Most of the authors worked for the developer of the compound; the result applies only to this form. early study signal We found no studies showing fewer fractures or higher bone density from boron supplements. currently not supported
Why your SHBG can drop – even without boron
An individual drop in SHBG can be real without proving a general effect of boron. SHBG responds to many factors, and many of them change exactly when someone starts a supplement (Szybiak-Skora et al., 2025):
- Liver: fatty liver and insulin resistance lower SHBG production.
- Insulin and body weight: overweight and visceral fat go along with lower SHBG; weight loss and fasting raise it.
- Energy intake: a calorie deficit and low energy availability shift SHBG and testosterone; in athletes, persistently low energy availability can lower testosterone (Mountjoy et al., 2023).
- Thyroid: an overactive thyroid raises SHBG, an underactive one lowers it.
- Medications and hormones: oestrogens, for example in oral contraceptives, raise SHBG; androgens lower it.
- Other supplements: starting magnesium, vitamin D or herbal “boosters” at the same time changes the baseline.
- Life stage: in women, SHBG changes across the menopausal transition (SWAN, 2024).
- Measurement: time of day, fasting and laboratory method change testosterone values; guidelines call for repeated morning measurements (Bhasin et al., 2018).
Lower is not automatically better. In observational studies, low SHBG is associated with insulin resistance and a higher risk of diabetes (SWAN, 2024; Szybiak-Skora et al., 2025). An SHBG value only makes sense together with total testosterone, albumin, measured or calculated free testosterone and estradiol (Bhasin et al., 2018; Vermeulen et al., 1999).
Who is most likely to benefit
These groups fit the available data best. A benefit has not been shown for any of them – these are the starting points where an effect is most plausible:
- People with a low-boron diet: little fruit, nuts and legumes. The metabolic studies found effects mainly after a low-boron diet (Nielsen et al., 1987). context-dependent
- People with marginal magnesium intake: the boron effect on minerals and hormones depended on magnesium (Nielsen et al., 1987). early study signal
- Men with a medically assessed, rather high SHBG who want to document their profile – as a self-experiment with measurement, not as treatment. mechanistically plausible
- People with knee discomfort looking specifically at the studied compound calcium fructoborate. early study signal
Who will probably notice little
- Well-supplied people with a plant-rich diet and normal hormone values.
- Strength athletes expecting muscle or strength gains: there was no effect in the bodybuilder study (Ferrando & Green, 1993). currently not supported
- People with an energy deficit, sleep deprivation or untreated conditions: these factors move hormones and SHBG more than a trace element does (Mountjoy et al., 2023; Leproult & Van Cauter, 2011).
- Anyone starting several products at once: a possible effect can no longer be recognised.
Dosing by goal: what was actually studied
This is not an intake recommendation. The overview separates normal intake, studied amounts and safety limits. All values refer to elemental boron unless stated otherwise.
| Context | Amount | Form, people, duration | Assessment |
|---|---|---|---|
| Natural intake | 0.87–1.35 mg per day | food; adults in the US; long term | well established as intake data |
| Supplement maximum (proposal) | 0.5 mg per daily dose | food supplements; adults; BfR | scientific proposal, not law |
| Knee discomfort (studied) | 220 mg calcium fructoborate per day, about 6.4 mg boron | 60 people with knee discomfort; 14 days | early study signal; this compound only |
| Minerals, hormones (studied) | 3 mg per day | postmenopausal women after a low-boron diet; weeks | early study signal; contradictory |
| Strength and testosterone (studied) | 2.5 mg per day | 19 training men; 7 weeks | currently not supported |
| SHBG, free testosterone (experimental) | 10 mg per day | 8 healthy men; 1 week; form not stated | early study signal; sits at the EU upper limit |
| EU safety limit | 10 mg per day | total intake from all sources; adults; EFSA | limit, not a target |
| US safety limit | 20 mg per day | total intake; adults aged 19 and over; Institute of Medicine | US standard, not transferable to the EU |
What follows: a generally effective dose is not known. The strongest hormone signal comes from the highest studied amount, which on its own already uses up the EU upper limit for total intake – food and drinking water come on top. Amounts in this range therefore belong under medical supervision. The BfR proposal for supplements is far lower; whether it measurably shifts hormone values has not been studied. Neither 10 nor 15 milligrams is a standard dose.
What you can measure before and after a trial
A clean N-of-1 experiment in six steps – as a documentation framework, not as therapy. Discuss the plan, the amount and the laboratory values with a doctor beforehand.
- Baseline values: two measurements one to two weeks apart before starting. This makes normal fluctuation visible.
- Choose the markers: SHBG, total testosterone, albumin, measured or calculated free testosterone, estradiol (Bhasin et al., 2018; Vermeulen et al., 1999). Useful companion markers: creatinine or eGFR, because boron is excreted via the kidneys; 25-OH vitamin D and magnesium if those axes interest you.
- Same conditions: morning, fasted, same weekday, same laboratory, same method.
- Keep companion factors constant: body weight, calorie intake, training, sleep, alcohol, medications and all other supplements stay unchanged. Only one variable changes.
- Set the period in advance: for example a defined intake phase, then the same measurement, then a break with another measurement. If an effect reverses after stopping, it is more credible.
- Define stopping criteria in advance: nausea, vomiting, diarrhoea or other new symptoms; unusual kidney or hormone values; a wish to conceive or pregnancy. Then stop and see a doctor.
Interpretation: a single value is not a result. Only a change larger than your own baseline fluctuation that shows up again on repetition is meaningful.
Why a single measurement can mislead
- Observed series after starting a supplement (solid, circles)
- Comparison series without intervention (dashed, squares)
- Personal average (dotted)
After the unusually high third measurement, the next measurement moves back closer to the average in both series. Schematic, without numbers and without patient data.
User experiences and their limits
Common observations: some people report lower SHBG values, higher free testosterone in the laboratory, more energy, better libido or less joint discomfort after a few weeks of boron. Others measure and feel no difference. anecdotal
These reports are often honestly measured. They just cannot answer what would have happened without boron. Hormone values fluctuate from one measurement to the next, an unusual starting value is often closer to the average next time, and many people start a diet, training or other supplements at the same time. Products also declare sometimes the compound and sometimes elemental boron – so experiences are hard to compare. A well-documented N-of-1 experiment following the scheme above is far more informative than a forum post. N-of-1
Combinations and possible synergies
None of the following combinations has a combination study with boron. The table therefore strictly separates shared mechanism, theoretical synergy, anecdotal reports and actual studies.
| Combination | Shared mechanism | Theory and reports | Combination studies |
|---|---|---|---|
| Boron + magnesium | mineral balance; the boron effect depended on magnesium status in one study | theoretical synergy with marginal intake; magnesium alone: small study with higher testosterone (Cinar et al., 2011) | none found |
| Boron + vitamin D | vitamin D metabolism; vitamin D rose in the boron study | theoretical; vitamin D alone did not change testosterone in healthy men (Lerchbaum et al., 2017) | none found |
| Boron + sleep optimisation | no shared mechanism; sleep acts directly on testosterone | one week of sleep restriction lowered testosterone (Leproult & Van Cauter, 2011); sleep is the bigger lever | none found |
| Boron + ashwagandha | both are marketed around hormones; mechanisms differ | ashwagandha alone: small, manufacturer-linked studies with higher testosterone (Lopresti et al., 2019; Wankhede et al., 2015); stack reports anecdotal | none found |
| Boron + tongkat ali | both are marketed around hormones; mechanisms differ | tongkat ali alone: rise mainly with testosterone deficiency (Leisegang et al., 2022); stack reports anecdotal | none found |
Biohacker rule for stacks: one variable per experiment. Starting boron together with magnesium, ashwagandha or tongkat ali produces an uncontrolled multiple intervention – and afterwards you cannot tell which ingredient did anything. Ashwagandha is associated with rare liver injury and is not permitted as a food in Denmark (LiverTox, Ashwagandha; Fødevarestyrelsen); for tongkat ali, EFSA could not confirm the safety of a root extract (EFSA, 2021; LiverTox, Tongkat Ali). Many “testosterone booster” blends contain ingredients without testosterone data and sometimes amounts above upper limits (Clemesha et al., 2020).
Safety and sensible limits
In short: the limits are based on reproductive and developmental effects in animal studies. They apply to total intake from food, water and supplements – and they are not a recommendation.
Upper limits and the BfR proposal at a glance
- EU · EFSA
10 mg of boron per day
Tolerable upper intake level for adults; total intake from food, water and supplements
- Germany · BfR
0.5 mg of boron per daily dose
Proposed maximum level in food supplements; a scientific proposal, not law
- US · Institute of Medicine
20 mg of boron per day
Tolerable upper intake level for adults aged 19 and over; total intake
Upper limit or BfR proposal – not an intake recommendation. The values have different reference points and must not be offset against each other.
EU and German values
- EFSA upper limit: 10 milligrams of boron per day for adults including pregnant and breastfeeding women; 3 mg (1–3 years), 4 mg (4–6 years), 5 mg (7–10 years), 7 mg (11–14 years), 9 mg (15–17 years). The basis is the EFSA opinion of 2004 (EFSA, 2004). The current EFSA overview of all upper limits, version 11 of August 2025, lists this value unchanged; no newer boron assessment is recorded there (EFSA overview, 2025).
- BfR maximum level proposal: at most 0.5 milligrams of boron per recommended daily dose of a food supplement, with a note that boron-containing products are not suitable for children and adolescents (BfR, proposed maximum levels).
- Food additives: a group ADI of 0.16 milligrams of boron per kilogram of body weight per day applies to the food additives boric acid and borax (EFSA, 2013).
- Calcium fructoborate: at most 220 milligrams of the compound per day, for adults only, not for pregnant or breastfeeding women (Commission Implementing Regulation (EU) 2021/2129).
US values
- Institute of Medicine upper limit: 20 milligrams of boron per day for adults aged 19 and over; lower age-dependent values for adolescents and children. The basis was reproductive and developmental effects in animal studies (Institute of Medicine, 2001).
International: drinking water
- WHO: guideline value of 2.4 milligrams of boron per litre of drinking water (WHO, 2022). Depending on the region, mineral water can also provide notable boron (BfR, 2006).
Borax is not a supplement
On social media, borax is promoted as a “cheap boron source”. That is dangerous. Borax is a chemical, classified as toxic for reproduction (Repr. 1B) and identified by ECHA as a substance of very high concern (ECHA, 2010). The fact that boric acid and sodium borate are listed as nutrient sources for supplements manufactured under controlled conditions does not turn household borax into a food. Never swallow household, cleaning, craft or industrial products containing borax or boric acid – not even diluted. In case of accidental ingestion, contact poison control.
Risk groups and interactions
- Pregnancy, breastfeeding, trying to conceive: the limits are based on developmental effects; the BfR counts pregnant and breastfeeding women among the risk groups (BfR, 2006). No self-experiment.
- Children and adolescents: boron-containing supplements are not suitable according to the BfR.
- Kidney disease: boron is excreted via the kidneys (Institute of Medicine, 2001); intake only under medical supervision.
- Hormone therapy and hormone-dependent conditions: because boron changed estradiol and testosterone, the BfR counts postmenopausal women on hormone replacement therapy and subfertile men among the risk groups (BfR, 2006).
- Overdose: very high intakes can affect the stomach, intestines, liver, kidneys and brain (ATSDR). For acute symptoms, seek medical help or contact poison control.
- Interactions: we found no verified human data on medicines. If you take medicines regularly, discuss it with a doctor or pharmacist first.
- Products: check that elemental boron per daily dose is declared, and count boron from multivitamin or “booster” products. Claims such as “boosts testosterone” are not authorised for foods (Regulation (EC) No 1924/2006; Regulation (EU) No 1169/2011).
Final verdict
Boron is biologically more active than its “non-essential” label suggests – and clinically far less researched than social media claims. The SHBG and testosterone signal is real, but it comes from a small short-term study using an amount at the EU upper limit. There is no effect on strength and muscle mass, no advantage for forms such as boron glycinate and no combination study for stacks.
For biohackers, this means: boron is a legitimate candidate for a well-planned self-experiment with two baseline measurements, constant companion factors, clear stopping criteria and a medical check-in – below the upper limits and with one variable. Anyone expecting quick strength gains will get more out of training, sleep and energy intake. And borax stays off limits.
Medical disclaimer
This article is for general information and does not replace medical or pharmaceutical advice. It contains no personal dosing recommendation. Hormonal symptoms, unusual laboratory values, a wish to conceive or menopausal symptoms belong with a doctor. Talk to a doctor or pharmacist before taking boron-containing products – especially during pregnancy or breastfeeding, with kidney, liver or thyroid disease, hormone therapy, regular medication or for minors.
You can find more topics in the knowledge section. If you want to approach training, load and recovery in a structured way, fitness coaching can support you – without medical diagnosis or treatment. You can record measurements and observations objectively in the Coach Cedric app.
Quick answers
Frequently asked questions about boron supplements
Does boron lower SHBG?
In one small study, yes: in eight healthy men, SHBG was lower six hours after 10 milligrams of boron. The study had no parallel placebo group and has not been independently replicated. That is an early study signal – whether the effect lasts and occurs reliably in other people has not been studied.
Does boron increase free testosterone?
In the same study, free testosterone rose after one week of 10 milligrams of boron per day. In a placebo-controlled study of 19 bodybuilders, 2.5 milligrams of boron over seven weeks changed neither free nor total testosterone, strength or lean mass. A hormone signal, yes; a performance effect is currently not supported.
What does boron glycinate offer compared with other forms?
We found no comparative human studies on boron glycinate, boron citrate or boron aspartate. Dietary boron is mostly converted to boric acid in the gut and well absorbed. What matters for comparison is the amount of elemental boron, not the name of the compound.
Can boron be combined with ashwagandha or tongkat ali?
There is no combination study for these stacks. The ingredients were studied individually; a joint effect is theoretically conceivable but not established. Ashwagandha and tongkat ali have their own safety questions, such as rare liver injury. Several products at once make any measurement impossible to interpret.
Is borax the same as boron?
No. Borax is a household and industrial chemical classified in the EU as toxic for reproduction. Household, cleaning or craft products containing borax must never be swallowed – not even diluted.
Is boron essential for humans?
That is not established. EFSA classifies boron as non-essential, and the US Institute of Medicine has not set a requirement. Boron is biologically active and changes mineral and hormone values in studies – there is still no recommended daily intake.
How much boron is considered safe?
For adults, EFSA sets a tolerable upper intake level of 10 milligrams of boron per day for total intake from food, water and supplements; the current EFSA overview from August 2025 confirms this. The BfR proposes a maximum of 0.5 milligrams per daily dose for food supplements. In the US, the upper limit is 20 milligrams. These are limits, not target amounts.
Do the results apply to women?
Not automatically. The SHBG study included only men. In postmenopausal women, estradiol and testosterone rose under 3 milligrams of boron in one small older study and did not change in a second. Human data for perimenopause are missing.
Which laboratory values should I measure in a self-experiment?
At minimum SHBG, total testosterone, albumin and measured or calculated free testosterone, plus estradiol – each in the morning, fasted, in the same laboratory and with the same method. Two baseline measurements before starting reveal normal fluctuation. Unusual values belong with a doctor.
Transparency
Sources and references
- Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines (Naghii et al., 2011)
- The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders (Ferrando & Green, 1993)
- Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women (Nielsen et al., 1987)
- The influence of a low-boron diet and boron supplementation on bone, major mineral and sex steroid metabolism in postmenopausal women (Beattie & Peace, 1993)
- Short-term efficacy of calcium fructoborate on subjects with knee discomfort (Pietrzkowski et al., 2014)
- Boron as a Context-Dependent System-Level Modulator: Mechanisms and Implications in Chronic Diseases (Tuzcu et al., 2026)
- Dietary Reference Intakes: Arsenic, Boron, Nickel, Silicon, and Vanadium (2001)
- New Insights in the Diagnostic Potential of Sex Hormone-Binding Globulin (SHBG) – Clinical Approach (Szybiak-Skora et al., 2025)
- Longitudinal Changes in Sex Hormone Binding Globulin (SHBG) and Risk of Incident Diabetes: The Study of Women’s Health Across the Nation (SWAN) (2024)
- Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline (Bhasin et al., 2018)
- A critical evaluation of simple methods for the estimation of free testosterone in serum (Vermeulen et al., 1999)
- Effects of magnesium supplementation on testosterone levels of athletes and sedentary subjects at rest and after exhaustion (Cinar et al., 2011)
- Vitamin D and Testosterone in Healthy Men: A Randomized Controlled Trial (Lerchbaum et al., 2017)
- Effect of 1 week of sleep restriction on testosterone levels in young healthy men (Leproult & Van Cauter, 2011)
- 2023 International Olympic Committee’s (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs) (Mountjoy et al., 2023)
- A Randomized, Double-Blind, Placebo-Controlled, Crossover Study Examining the Hormonal and Vitality Effects of Ashwagandha (Withania somnifera) in Aging, Overweight Males (Lopresti et al., 2019)
- Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial (Wankhede et al., 2015)
- LiverTox: Ashwagandha
- Ashwagandha
- Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials (Leisegang et al., 2022)
- LiverTox: Tongkat Ali
- Safety of Eurycoma longifolia (Jack) root extract as a novel food pursuant to Regulation (EU) 2015/2283 (2021)
- ‘Testosterone Boosting’ Supplements Composition and Claims Are not Supported by the Academic Literature (Clemesha et al., 2020)
- Overview on Tolerable Upper Intake Levels as derived by the Scientific Committee on Food (SCF) and the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA), Version 11 (August 2025)
- Opinion of the Scientific Panel on Dietetic Products, Nutrition and Allergies related to the Tolerable Upper Intake Level of Boron (Sodium Borate and Boric Acid) (2004)
- Scientific Opinion on the re-evaluation of boric acid (E 284) and sodium tetraborate (borax) (E 285) as food additives (2013)
- Proposed maximum levels for boron in foods including food supplements
- Addition of boric acid or borax to food supplements (Health Assessment No. 005/2006)
- Safety of calcium fructoborate as a novel food pursuant to Regulation (EU) 2015/2283 (2021)
- Commission Implementing Regulation (EU) 2021/2129 authorising calcium fructoborate as a novel food
- Directive 2002/46/EC on food supplements (consolidated version of 6 February 2024)
- Regulation (EC) No 1924/2006 on nutrition and health claims made on foods
- Regulation (EU) No 1169/2011 on the provision of food information to consumers
- Support document for identification of disodium tetraborate, anhydrous as a substance of very high concern (2010)
- Guidelines for Drinking-water Quality: Chemical fact sheet Boron (2022)
- ToxFAQs: Boron