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Tribulus Terrestris for Testosterone

Verdict: Tribulus does not raise testosterone

Despite being heavily marketed as a "natural testosterone booster," Tribulus terrestris does not meaningfully raise testosterone in healthy or athletic men. Human clinical trials and systematic reviews consistently find no effect, and major regulators and clinics reject the claim.

D 🔴 D Counter-Evidence Counter-Evidence

🔬Why this grade7-layer evidence engine

This earns a Counter-Evidence grade because the human data directly contradict the marketing. A double-blind RCT in healthy young men (PMID 15994038) found no significant difference in testosterone versus placebo, and a double-blind RCT in elite rugby players (PMID 17530942) found no change in the androgen profile. An open-label trial in infertile men (PMID 27337519) likewise showed no significant change in total testosterone, free testosterone, or LH.

Higher-tier reviews confirm the pattern, which is why these trials cannot be overridden by isolated positive reports. A 2014 systematic review of 11 studies (PMID 24559105) concluded Tribulus is ineffective at raising testosterone in humans, with androgen elevation seen only in animal studies. A 2025 systematic review of 483 men (PMID 40219032) found no androgen change in 8 of 10 trials; the only increases, a modest 60-70 ng/dL, appeared in two studies of hypogonadal men, not the general population the product targets.

Regulators and clinics align with this conclusion. The Mayo Clinic states there is no clinical evidence that over-the-counter boosters actually increase testosterone, Harvard Health is skeptical, the FDA has approved no such claim, and the EU's EFSA rejected the related health claims. For raising testosterone in typical men, the supplement is best viewed as not working.

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Scoring transparency

All scores computed by a 7-layer evidence engine — fully auditable
Raw score 0.25
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
D · Counter-Evidence
Confidence
80%
Broadly consistent
Evidence level
E2
Multiple high-quality MAs (≥2 independent, consistent)

How strongly each layer supports this effect

lower = less supportive
L2 PubMedPrimary literature
0.20
L5 Clinical bodiesAuthoritative stance
0.23
L3 MechanismPlausibility
0.25
L11 AI re-checkIndependent read
0.30
L1 ExamineGlobal benchmark
0.50
Against Mixed Supports
▸View the full decision path (audit trail)
  1. compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.248
  2. tier_from_score — 依分數區間映射至 tier letter
  3. apply_hec_rules — 高品質 SR/MA 顯示 negative 主導 (2 negative > 0 positive)，下層 RCT 不能推翻
  4. apply_hec_override — HEC-1 高階證據 negative — 強制由 U 改為 D
  5. tier_strict_requirement_check — Tier 條件達標，未降階
  6. detect_disputes — 偵測到 0 個 hard + 1 個 soft dispute
  7. decide_status — 依 tier + dispute 結果決定 status

📄PubMed studies (5)L2 · primary research & systematic reviews

The aphrodisiac herb Tribulus terrestris does not influence the androgen production in young men
PMID: 15994038 2005 RCT (double-blind) n = 21
Finding: No significant differences in testosterone between TT1 (15.75 nmol/l), TT2 (16.32 nmol/l), and controls (17.74 nmol/l); p > 0.05 for all comparisons.
Effect size: MD approximately -2 nmol/l (non-significant), all values within normal range
View on PubMed
The effect of five weeks of Tribulus terrestris supplementation on muscle strength and body composition during preseason training in elite rugby league players
PMID: 17530942 2007 RCT (double-blind) n = 22
Finding: No between-group differences in urinary T/E ratio; TT did not alter androgen profile and would not trigger WADA doping violation (T/E < 4:1).
Effect size: null
View on PubMed
Prospective Analysis on the Effect of Botanical Medicine (Tribulus terrestris) on Serum Testosterone Level and Semen Parameters in Males with Unexplained Infertility
PMID: 27337519 2017 RCT (open-label) n = 30
Finding: No statistically significant difference in total testosterone, free testosterone, or LH before and after treatment; TT ineffective for hormonal parameters.
🟠 Limited quality Effect size: null
View on PubMed
A systematic review on the herbal extract Tribulus terrestris and the roots of its putative aphrodisiac and performance enhancing effect
PMID: 24559105 2014 系統性回顧
Finding: 11 studies reviewed; TT is ineffective for increasing testosterone levels in humans; marketing claims are unsubstantiated; only animal studies showed androgen elevation.
Effect size: null
View on PubMed
Effects of Tribulus (Tribulus terrestris L.) Supplementation on Erectile Dysfunction and Testosterone Levels in Men—A Systematic Review of Clinical Trials
PMID: 40219032 2025 系統性回顧 n = 483
Finding: 8 out of 10 studies showed no significant changes in androgen profile; only 2 studies (in hypogonadal men) reported modest increases of 60-70 ng/dL; overall low level of evidence for testosterone elevation.
Effect size: 60-70 ng/dL increase in 2 outlier studies (hypogonadal populations only)
View on PubMed

🏛️Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …

L4a US FDA
Cautious
L4b EU EFSA
Against
L4d TW TFDA / 衛福部
Cautious
須由中醫師處方使用（白蒺藜，衛署藥製字第011641號）；未經確認其食用安全性前，不得供為食品原料使用。 source↗
L5a NIH Office of Dietary Supplements
Cautious
L5b Mayo Clinic
Against
there is no clinical evidence to show that over-the-counter supplements like [testosterone boosters] actually increase testosterone levels source↗
L5d Harvard Health
Against
L5e Specialty Society (condition-mapped)
Not addressed
✓PMID 100% verifiedevery citation checked via NCBI Entrez
🔬5 PubMed studiesindependently re-checked by multiple sub-agents
engine_version: v1.0 claim_id: CLM-COND-testosterone-INT-tribulus-terrestris-001 繁體中文版 →