Forskolin (Coleus forskohlii) for Testosterone

Verdict: Weak, unreplicated evidence for raising testosterone

There is not enough evidence that forskolin (Coleus forskohlii) raises testosterone. The entire claim rests on a single small, industry-funded trial that has gone unreplicated for nearly two decades, and no major clinical guideline recommends it.

C 🟠 C Weak Evidence Disputed

🔬Why this grade7-layer evidence engine

The testosterone signal traces to just one study: Godard 2005 (PMID 16129715), a double-blind RCT in 30 overweight and obese men taking Coleus forskohlii (250 mg standardized to 10% forskolin) twice daily for 12 weeks. Free testosterone rose about 17% versus placebo, but this was a secondary endpoint in a trial designed around body composition, the study was industry-funded and single-center, and no confirmatory RCT or meta-analysis has reproduced the effect on PubMed since 2005.

Clinical authorities give it no support. The American Urological Association and Endocrine Society testosterone-deficiency guidelines never mention forskolin, instead recommending lifestyle modification and prescription therapy; Cleveland Clinic and Harvard Health are likewise silent. On the regulatory side, the US FDA has only issued warning letters over disease claims (not testosterone), and the EU EFSA has not accepted forskolin health claims, keeping them on-hold with no established causal relationship.

The proposed mechanism (cAMP upregulation) is biologically plausible but unconfirmed in humans, and the lone positive result applies only to overweight men, not healthy or low-testosterone populations. Taken together this is weak, disputed evidence: a single small trial with no replication and no clinical endorsement does not justify marketing forskolin as a testosterone booster.

⚖️

Scoring transparency

All scores computed by a 7-layer evidence engine — fully auditable
Raw score 0.41
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
C · Disputed
Confidence
70%
Broadly consistent
Evidence level
E7
Single small RCT

How strongly each layer supports this effect

lower = less supportive
L2 PubMedPrimary literature
0.40
L1 ExamineGlobal benchmark
0.50
L3 MechanismPlausibility
0.50
L11 AI re-checkIndependent read
0.50
L5 Clinical bodiesAuthoritative stance
0.55
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 = 0.413
  2. tier_from_score — 依分數區間映射至 tier letter
  3. apply_hec_rules — 無高階證據可裁決
  4. tier_strict_requirement_check — Tier 條件達標,未降階
  5. detect_disputes — 偵測到 1 個 hard + 1 個 soft dispute
  6. decide_status — 依 tier + dispute 結果決定 status

📄PubMed studies (1)L2 · primary research & systematic reviews

Body composition and hormonal adaptations associated with forskolin consumption in overweight and obese men (Godard et al.)
PMID: 16129715 2005 RCT (double-blind) n = 30
Finding: Free testosterone increased 16.77% in forskolin group vs decrease in placebo (p<=0.05) as a secondary endpoint; primary outcome was body composition (decreased fat mass, increased lean mass). Small single-center pilot in overweight/obese men.
⚠️ Industry-funded Effect size: +16.77% free testosterone vs placebo (secondary endpoint, n=30)
View on PubMed

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

L4a US FDA
Cautious
Coleus forskohlii [an ingredient in Blood Pressure Support] contains a chemical called forskolin, which is known for having the ability to reduce blood pressure source↗
L4b EU EFSA
Against
L4d TW TFDA / 衛福部
Neutral
毛喉鞘蕊花(Coleus forskohlii)列於食藥署「可供食品使用原料彙整一覽表」之草、木本植物類,可供直接食品使用,使用部位為根。 source↗
L5a NIH Office of Dietary Supplements
Cautious
L5e Specialty Society (condition-mapped)
Not addressed
All men with testosterone deficiency should be counseled regarding lifestyle modifications as a treatment strategy. source↗
PMID 100% verifiedevery citation checked via NCBI Entrez
🔬1 PubMed studiesindependently re-checked by multiple sub-agents
engine_version: v1.0 claim_id: CLM-COND-testosterone-INT-forskolin-001 繁體中文版 →