In 30 seconds
Evidence: In a 2013 trial, 200mg/day of standardised Tongkat Ali extract was associated with measured changes in cortisol and testosterone over four weeks — trial evidence, not a claim about this product.
Timing: Cortisol follows a diurnal rhythm and responds to sleep, training load and stress over several weeks, so one measurement is a snapshot rather than a trend.
Next step: Get your own baseline (e.g. testosterone, cortisol, vitamin D) via your GP or a UK service such as Medichecks or Thriva — numbers to track over time.
Tongkat Ali (Eurycoma longifolia) is a flowering plant native to the rainforests of Malaysia, Indonesia, and Thailand. Known locally as "Malaysian ginseng," it has been used in Southeast Asian traditional medicine for centuries — and it has since been examined in a growing number of clinical trials. In a 2013 randomised controlled trial of 63 moderately stressed adults, 200mg/day of standardised Tongkat Ali extract was associated with a 16% reduction in cortisol and a 37% change in total testosterone over four weeks (Talbott et al., JISSN, 2013). These are research findings about the doses studied; they cannot be transferred to any finished product as label claims.
A 2022 meta-analysis of five RCTs then confirmed the trend: across study populations, Tongkat Ali was associated with a statistically significant difference in total testosterone (SMD 1.352, 95% CI 0.565–2.138, p=0.001) in both healthy and hypogonadal men (Leisegang et al., Medicina, 2022). The available trials included several populations, including stressed adults and men with low baseline testosterone. Findings apply only to the extracts, doses and populations studied. This guide reviews that evidence and its limitations for UK readers.
- A 2022 meta-analysis of 5 RCTs found a statistically significant difference in total testosterone associated with Tongkat Ali (SMD 1.352, p=0.001) — a research finding, not a finished-product label claim
- In stressed adults, cortisol fell by 16% and total testosterone differed by 37% from baseline in just 4 weeks at 200 mg/day (Talbott 2013) — doses studied; not transferable to a finished product
- In Chinnappan et al. (2021, n=105), changes in testosterone, muscle strength and cortisol were reported after 12 weeks at the studied 200mg/day dose. This is a research finding, not a finished-product claim
- Key active compound: eurycomanone — look for extracts standardised to 1–1.5% eurycomanone (Malaysian Standard MS 2409:2011)
- Some trials enrolled men with low or borderline baseline values or higher stress. Findings apply only to those study populations and doses
- UK regulatory status should be checked against current FSA guidance. Trials studied 100–400mg/day of standardised extract
Looking for a Daily Formula Without Tongkat Ali?
Important: Blue Power does not contain Tongkat Ali or Fadogia agrestis. It is a separate UK-made, once-daily food supplement with seven clearly listed ingredients and no proprietary blend.
- See the Blue Power overview.
- Start with the 20-tablet starter pack.
- Compare 20, 40 and 80-tablet packs and their cost per tablet.
Zinc contributes to the maintenance of normal testosterone levels in the blood. Vitamin C contributes to the reduction of tiredness and fatigue (EFSA authorised claims).
What Is Tongkat Ali and How Does It Work?
Tongkat Ali (literally "Ali's walking stick" in Malay) is a slow-growing understory tree of the Simaroubaceae family. It reaches up to 15 metres tall but grows painfully slowly — a mature tree can take 10–15 years to develop. The medicinal part is the root, which is extraordinarily bitter (locals call it "bitter root") and rich in a class of compounds called quassinoids.
Eurycomanone is a quassinoid used as a standardisation marker for Tongkat Ali extracts. Laboratory and animal studies have examined several possible mechanisms, but the mechanisms underlying human clinical findings remain uncertain and do not establish a benefit.
Glycosaponins are another compound class examined in Tongkat Ali research. The trials reviewed measured specific hormone, stress and other clinical markers; they did not establish stimulant-like energy effects or predict an individual response. Findings cannot be transferred to a finished product as label claims.
The Malaysian Standard MS 2409:2011 sets quality benchmarks for Tongkat Ali products: eurycomanone 0.80–1.50% by weight, total polysaccharides >30%, total protein >20%, total glycosaponin >40%. Most clinical trials used Physta®, a patented hot-water root extract manufactured by Biotropics Malaysia that meets this standard. When buying in the UK, look for a product that specifies eurycomanone content — if the label just says "Tongkat Ali extract" without a standardisation percentage, you can't compare it to the clinical evidence.
A 2014 review in Andrologia discussed differences between the populations studied and reported no significant toxicity at the concentrations examined (George & Henkel, Andrologia, 2014). These findings are population-specific and cannot predict an individual response or support a finished-product claim.
What Have Clinical Trials Studied About Tongkat Ali?
1. Testosterone Outcomes Studied in Trials Meta-analysis
The most robust evidence comes from a 2022 meta-analysis pooling five randomised controlled trials. In this meta-analysis, a statistically significant between-group difference in total testosterone was reported (SMD 1.352, 95% CI 0.565–2.138, p=0.001). These findings concern the study populations and doses and cannot be transferred to a finished product as a claim (Leisegang et al., Medicina, 2022).
The most detailed dose-response data comes from a 2021 double-blind, placebo-controlled RCT of 105 men aged 50–70 with testosterone below 300ng/dL. The authors reported between-group changes in testosterone markers at weeks 4, 8 and 12 in the 200mg/day group, while a change was reported at week 12 in the 100mg group. Changes in DHEA and cortisol markers were also reported (Chinnappan et al., Food & Nutrition Research, 2021).
Editorial note — what this means in context: The meta-analysis result (SMD 1.352, p=0.001) is statistically robust, but the clinical picture is more nuanced than a simple hormone-level story. Larger changes were reported in some study groups with low baseline testosterone or elevated cortisol. The 2024 trial in trained participants reported no significant change. Results are population-specific and do not predict an individual response.
— Blue Power Research Team, reviewing Leisegang et al. (2022)Study Funding Transparency
Understanding who funded each study helps weigh the evidence properly. Most Tongkat Ali clinical trials used Physta, a patented extract manufactured by Biotropics Malaysia:
| Study | Sample | Funding / Extract | Status |
|---|---|---|---|
| Talbott 2013 (cortisol/T) | n=63, stressed adults | Biotropics Malaysia (Physta) | Industry |
| Chinnappan 2021 (hypogonadal) | n=105, men 50–70 | Biotropics Malaysia (Physta) | Industry |
| Ismail 2012 (sexual function) | n=109, men 30–55 | Biotropics Malaysia (Physta) | Industry |
| Tambi 2010 (fertility)* | n=75, infertile men | Not declared / hospital-led | Independent |
| Applied Sciences 2024 (null result) | n=33, trained athletes | University research | Independent |
| Leisegang 2022 (meta-analysis) | 5 RCTs pooled | Academic review, no declared funding | Independent |
*Open-label study without placebo control.
Most positive RCTs were funded by the manufacturer of Physta extract. The independently funded meta-analysis (Leisegang 2022) pooled five RCTs and reported a statistically significant between-group difference. The independently funded 2024 study reported no significant change in trained participants. Together, the results show substantial differences between study populations.
2. Cortisol and Stress Markers One RCT
Clinical studies have examined cortisol and testosterone markers in specific populations; the findings do not establish a benefit for an individual or finished product. In Talbott's 2013 RCT of 63 moderately stressed adults, 200mg/day of Tongkat Ali for 4 weeks was associated with a 16% reduction in cortisol and a 37% change in total testosterone from baseline. The same study measured mood states: tension dropped 11%, anger 12%, and confusion 15% (all p<0.05) (Talbott et al., JISSN, 2013).
In Chinnappan et al. (2021, n=105), changes in cortisol and testosterone markers were reported in the 200mg/day group. The findings concern the studied extract, dose and population and cannot be transferred to a finished product as a claim (Chinnappan et al., 2021).
3. Male Fertility & Sperm Quality
In an open-label study of 75 infertile men (no placebo control), 200mg/day of Tongkat Ali for up to 9 months reported changes across semen parameters including volume, concentration, motility and morphology. During the uncontrolled study, 14.7% of couples reported spontaneous pregnancy (11 out of 75) during the treatment period (Tambi et al., Asian Journal of Andrology, 2010). Note: as an open-label study without a placebo arm, these results are suggestive rather than definitive.
A separate 12-week RCT in 109 men aged 30–55 reported between-group changes in sperm motility and semen volume at 300mg/day (Ismail et al., Evidence-Based Complementary and Alternative Medicine, 2012). For men considering both fertility and general wellbeing, these findings concern the studied extract and dose; larger placebo-controlled trials are needed.
4. Sexual Function & Wellbeing
The Ismail 2012 RCT also measured sexual function using the International Index of Erectile Function (IIEF): changes in IIEF domain scores and self-reported sexual desire were reported at 300mg/day over 12 weeks. A 2015 meta-analysis of two RCTs also reported between-group differences in participants with lower baseline IIEF scores. These dose-specific research findings cannot be transferred to a finished product as claims (Kotirum et al., Complementary Therapies in Medicine, 2015).
A 6-month RCT in 45 men with androgen deficiency of ageing (mean age 47) found that 200mg/day Tongkat Ali alongside concurrent exercise training was associated with a greater change in erectile-function scores and total testosterone than exercise alone (Leitao et al., Maturitas, 2021). These are research findings about the 200mg dose studied and cannot be transferred to any finished product as label claims.
5. Muscle Strength & Physical Performance
In Chinnappan et al. (2021, n=105), between-group differences in measured strength were reported at 200mg/day over 12 weeks. Henkel et al. (2014, n=25) reported changes in testosterone markers and muscular-force measurements at 400mg/day over five weeks. These findings concern the study populations and doses and cannot support a finished-product claim (Henkel et al., Phytotherapy Research, 2014).
The caveat: the 2024 study in already-trained athletes found no effect on strength or body composition at 400mg/day over 4 weeks. Results differed between the populations studied, including a null 2024 trial in trained participants. The evidence cannot predict an individual response or support a finished-product claim.
6. Body Composition
In Ismail et al. (2012), a between-group difference in fat mass was reported among participants with BMI ≥25 at 300mg/day. The trial did not establish the mechanism responsible and cannot predict an individual weight outcome.
What Tongkat Ali Doses Have Clinical Trials Studied?
| Study | Dose | Duration | Population | Reported Outcome |
|---|---|---|---|---|
| Talbott 2013 | 200mg/day | 4 weeks | Stressed adults (n=63) | Changes in cortisol and testosterone markers reported |
| Chinnappan 2021 | 200mg/day Frequently Studied | 12 weeks | Hypogonadal men 50–70 (n=105) | Between-group changes in testosterone and strength markers reported |
| Ismail 2012 | 300mg/day | 12 weeks | Men 30–55 (n=109) | Changes in IIEF and sperm-motility measures reported |
| Tambi 2010* | 200mg/day | Up to 9 months | Infertile men (n=75) | Pregnancy observed in 11/75; semen-parameter changes reported |
| Henkel 2014 | 400mg/day | 5 weeks | Active seniors 57–72 (n=25) | Changes in testosterone and muscular-force measurements reported |
| Leitao 2021 | 200mg/day | 6 months | Men with ADAM, ~47yr (n=45) | Between-group changes in IIEF and testosterone markers reported alongside exercise |
*Open-label study (no placebo control). All other studies listed are double-blind, placebo-controlled RCTs. Outcomes concern the listed study doses and are not finished-product claims.
Clinical trials studied 100–400mg/day. In Chinnappan et al. (2021, n=105), different between-group changes were reported at 100mg and 200mg over 12 weeks. These findings are specific to the studied extract, doses and population and are not a dosing recommendation.
Is Tongkat Ali Safe? Side Effects & the EFSA Question
Across the cited RCTs, no serious adverse events were reported at 100–400mg/day over the studied durations. Minor adverse effects included restlessness, insomnia and digestive discomfort. The George and Henkel review reported no significant toxicity in the studies and doses it examined, but this does not establish general safety; EFSA's later assessment raised genotoxicity concerns (Andrologia, 2014).
The EFSA Novel Food Assessment
In December 2021, EFSA's NDA Panel assessed a Tongkat Ali novel-food preparation and concluded that safety had not been established because of genotoxicity concerns (EFSA Journal 19(12):6937, 2021). Animal-study doses and human trial doses differ, but that difference should not be used to infer safety. Check current regulatory guidance and consult a healthcare professional before use.
- Men on blood pressure medication: Tongkat Ali may have mild blood pressure effects
- Anticoagulant therapy (warfarin, aspirin): Limited data on interactions
- Diabetes medication: May affect blood glucose regulation
- Hormone-sensitive conditions: Hormone-related markers have been examined in limited studies; consult a healthcare professional before use
- Liver conditions: LiverTox classifies it as a "possible rare cause" of liver injury based on a single case report (NCBI LiverTox)
- Under 18s and pregnant/breastfeeding women: Not studied in these groups
UK regulatory status can change and retail availability does not itself establish authorisation. Check the current Food Standards Agency guidance and the seller's documentation before purchasing a Tongkat Ali product.
Human trials at 100–400mg/day reported limited adverse-event data over their studied durations, but they were not designed to resolve EFSA's genotoxicity concern. Consult a healthcare professional before use, particularly if you take medication or have a medical condition.
Editorial note — safety in context: The EFSA opinion is worth reading in full rather than reacting to the headline. The genotoxicity signal came from chromosome aberration assays at 2,000mg/kg in rats — that's the human equivalent of swallowing an entire bottle of supplements in one sitting. At the 200–400mg/day doses used in clinical trials, the safety data across multiple studies lasting up to 9 months is consistent and reassuring. That said, men with pre-existing liver conditions should err on the side of caution and consult their GP.
— Blue Power Research Team, reviewing the EFSA 2021 safety assessmentHow Do You Choose Quality Tongkat Ali in the UK?
The surge in popularity — driven partly by podcast recommendations and social media — has flooded the UK market with products of wildly varying quality. Here's what separates a well-standardised, GMP-certified Tongkat Ali product from marketing noise:
- Eurycomanone standardisation: Look for at least 1% eurycomanone by weight. The Malaysian Standard MS 2409:2011 specifies 0.80–1.50%. Products claiming "100:1 extract" or "200:1 concentration" without specifying eurycomanone content are using meaningless ratios — a 200:1 extract tells you nothing about the actual bioactive content.
- Extraction method: Clinical trials used hot-water extraction (aqueous extraction). Alcohol-based or chemical extractions may concentrate different compounds. If the product doesn't specify extraction method, ask.
- Third-party testing: Heavy metals (lead, arsenic, mercury), microbial contamination, and identity testing. A Certificate of Analysis (CoA) should be available on request.
- GMP certification: UK or EU Good Manufacturing Practice standards ensure consistent production quality.
- Dose transparency: Avoid proprietary blends that hide individual ingredient amounts. You should know exactly how many milligrams of Tongkat Ali you're getting per serving.
Tongkat Ali vs Other Herbal Supplements for Men: How Does It Compare?
The evidence bases differ in study count, population, dose and design, so these ingredients cannot be compared directly. Tongkat Ali has been assessed in a five-RCT meta-analysis; the other ingredients have separate and differently limited evidence bases. These research findings are not finished-product claims.
Tongkat Ali and shilajit have been examined separately in laboratory and clinical research. Proposed mechanisms remain under investigation and cannot be transferred to a finished product as claims.
Reporting side effects. Food supplements are generally well tolerated, but if you notice an unexpected reaction to any supplement you can report it to the UK regulator through the MHRA Yellow Card Scheme. Always tell your GP or pharmacist about supplements you take, especially alongside prescription medicines.
Why Blue Power uses these doses
Blue Power is a once-daily multi-ingredient tablet, not a single high-dose extract. That is a deliberate design choice, and it explains why some ingredient amounts are lower than the doses used in single-ingredient clinical trials.
Each ingredient is included at an amount tied to its own nutritional role and to UK safe-intake limits. For example, zinc is included at 10 mg — 100% of the EU Nutrient Reference Value — which is the amount at which the authorised claim applies: “Zinc contributes to the maintenance of normal testosterone levels in the blood.” Larger amounts are not more useful: the 2020 FAZST trial found no benefit from high-dose zinc in men who already had enough, and intakes above 40 mg/day risk copper depletion.
Blue Power does not contain Tongkat Ali or Fadogia agrestis. Research on those ingredients cannot be transferred to Blue Power as a product claim.
Frequently Asked Questions About Tongkat Ali UK
What is Tongkat Ali and what does it do for men?
Tongkat Ali (Eurycoma longifolia) is a flowering plant native to Southeast Asian rainforests, traditionally used in Malaysian and Indonesian medicine. In a 2013 RCT (Talbott et al., JISSN, n=63, 200mg/day, four weeks), changes in cortisol and testosterone markers were reported in moderately stressed adults (PubMed 23705671). In Leisegang et al. (2022), a meta-analysis of five RCTs, a statistically significant between-group difference in total testosterone was reported (SMD 1.352, p=0.001). These findings concern the extracts, doses and populations studied and cannot be transferred to a finished product as claims.
Is Tongkat Ali legal in the UK?
UK regulatory status can change. Check current Food Standards Agency guidance and the seller's documentation before purchase. EFSA's 2021 safety assessment raised genotoxicity concerns, so availability alone should not be treated as evidence of authorisation or safety.
How much Tongkat Ali should men take per day?
Clinical trials used 100–400mg/day of standardised extract, with 200mg/day frequently studied. In Chinnappan et al. (2021, n=105), different testosterone-marker changes were reported between the 100mg and 200mg groups over 12 weeks. These findings apply only to the studied doses and are not label claims or dosing recommendations.
What does the clinical evidence say about Tongkat Ali and testosterone?
A 2022 meta-analysis of five RCTs reported a statistically significant between-group difference in total testosterone (SMD 1.352, p=0.001). A 2024 study reported no significant change in exercise-trained participants. Results differed across the populations studied and cannot predict an individual response or be transferred to a finished product as a claim.
What is eurycomanone and why does it matter?
Eurycomanone is the primary bioactive quassinoid compound in Tongkat Ali root; in laboratory and animal studies it has been investigated as the compound behind most of Tongkat Ali's studied effects. The Malaysian Standard MS 2409:2011 specifies 0.80–1.50% eurycomanone for quality extracts. When buying Tongkat Ali in the UK, look for products standardised to at least 1% eurycomanone. Ignore extract ratios like "100:1" — they don't tell you the actual bioactive content.
Are there any side effects of Tongkat Ali?
Across the cited trials, no serious adverse events were reported at 100–400mg/day over 4 weeks to 9 months, but the evidence is limited and EFSA’s 2021 assessment raised genotoxicity concerns. Minor side effects can include restlessness, insomnia (if taken late in the day), and mild digestive discomfort. EFSA flagged genotoxicity concerns at extremely high rat doses (2000mg/kg), but human clinical trials at standard doses reported no serious adverse events. Men on blood pressure medication, anticoagulants, or diabetes drugs should consult their GP before use.
The Bottom Line: Is Tongkat Ali Worth It for UK Men Over 40?
Tongkat Ali has been examined in a meta-analysis of five RCTs, while many other herbal ingredients have smaller or differently designed evidence bases. This difference in study design does not establish superior efficacy or predict an individual response. The reported findings remain specific to the extracts, doses and populations studied.
Trial outcomes differed by baseline status and study population, including a null result in trained participants. The evidence remains limited and cannot predict an effect for an individual.
Quality is everything. Standardised hot-water root extract with verified eurycomanone content, not "100:1" marketing ratios. For men who want Tongkat Ali as part of a daily supplement that includes other ingredients, look for full-dose transparency and third-party testing.
On one common co-ingredient: Zinc contributes to the maintenance of normal testosterone levels in the blood.
References & Sources (expand)
- Talbott SM et al. (2013). Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. Journal of the International Society of Sports Nutrition 10(1):28. PubMed 23705671
- Leisegang K et al. (2022). Eurycoma longifolia (Jack) Improves Serum Total Testosterone in Men: A Systematic Review and Meta-Analysis of Clinical Trials. Medicina 58(8):1047. PubMed 36013514
- Chinnappan SM et al. (2021). Efficacy of Physta water extract on testosterone and physical performance in elderly men with testosterone deficiency. Food & Nutrition Research 65:5647. PubMed 34262417
- Ismail SB et al. (2012). Randomized Clinical Trial on the Use of PHYSTA for the Improvement of Quality of Life and Sexual Well-Being in Men. Evidence-Based Complementary and Alternative Medicine 2012:429268. PubMed 23243445
- Tambi MIBM et al. (2010). Standardised water-soluble extract of Eurycoma longifolia for managing men with late-onset hypogonadism. Asian Journal of Andrology 12(3):376-80. PubMed 20348942
- Leitao AE et al. (2021). A 6-month randomized controlled trial comparing Eurycoma longifolia combined with concurrent training versus concurrent training alone. Maturitas 145:78-85. PubMed 33541567
- Henkel RR et al. (2014). Tongkat Ali as a potential herbal supplement for physically active male and female seniors. Phytotherapy Research. PubMed 23754792
- George A & Henkel R (2014). Phytoandrogenic properties of Eurycoma longifolia. Andrologia 46(7):708-21. PubMed 24386995
- Kotirum S et al. (2015). Efficacy of Tongkat Ali on erectile function improvement: systematic review and meta-analysis. Complementary Therapies in Medicine 23(5). PubMed 26365449
- EFSA NDA Panel (2021). Safety of an aqueous extract from the roots of Eurycoma longifolia as a novel food. EFSA Journal 19(12):6937. PubMed 34987621
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury — Tongkat Ali. NCBI LiverTox NBK609015
- Applied Sciences (2024). Effect of Tongkat Ali on free testosterone, body composition and strength in trained men and women. 14(11):4372. MDPI
- Martin LJ et al. (2021). The Effect of Herbal Supplements on Clinical Testosterone Concentrations: A Systematic Review. Nutrients 13(5). PMC8166567
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