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Butea superba

Butea superba
Evidence Level
Limited
2 Clinical Trials
5 Documented Benefits
2/5 Evidence Score

Butea superba is a Thai herb, often called red kwao krua, marketed for male libido, erectile function, and vitality, and traditionally used as a male tonic; it is essentially the male counterpart to the female-oriented Pueraria mirifica. It is used as a standardized root extract, with limited human research suggesting possible benefit for libido and sexual function, so claims should be viewed cautiously. Human safety data is limited, and because it may have hormonal activity, those with hormone-sensitive conditions should be cautious; quality and sourcing vary, so it is best to choose tested products and check with a doctor before use, especially if on medication.

Studied Dose 250-500 mg dried tuber 1-3×/day. Caution: hyperandrogenemia case report; limit duration and dose.
Active Compound Flavonoids (medicarpin, formononetin), butein, butin, sterols (β-sitosterol, stigmasterol), and tuber-specific phytoandrogenic compounds.

Benefits

Erectile Dysfunction (One Small RCT)

A randomized double-blind trial in Thai males aged 30-70 with ED showed significant improvement in 4 of 5 IIEF-5 questionnaire domains over 3 months, with 82.4% of patients reporting noticeable improvement and no apparent change in hematology or blood chemistry. Important: small single-trial evidence — not replicated in larger Western populations.

Supported by Trial 1

Possible cAMP PDE Inhibition (Mechanism for ED Effect)

Compounds isolated from Butea superba tuber show inhibitory effects on cAMP phosphodiesterase higher than caffeine and theophylline in vitro. This mechanism overlaps with PDE5 inhibitors (sildenafil) for erectile function — though specific PDE5 selectivity is unclear. Mechanism-based explanation for the ED trial findings.

Supported by Trial 1, Trial 2

Possible Androgenic / Phytoandrogen Activity

Animal studies and a human case report document androgen elevation — specifically dihydrotestosterone (DHT) increases. The case showed DHT 1512 pg/mL (reference 250-990) after a few weeks of Butea capsules. This has been characterized both as a desired effect (for libido) and as an adverse hyperandrogenism event.

Supported by Trial 2

Traditional Thai Use for Vitality

Known as Red Kwao Krua in Thailand, Butea superba is traditionally classified as a 'rejuvenating' herb for aging men, paralleling Pueraria mirifica (White Kwao Krua) for women. Used historically to promote vitality, libido, and physical strength. Most evidence remains traditional rather than RCT-confirmed.

Supported by Trial 1, Trial 2

Possible Improved Penile Blood Flow (Animal)

Diabetic rat studies show Butea superba enhanced penile erection by increasing intracavernous pressure (ICP), explained by relaxation of cavernous smooth muscle and increased blood flow. Provides preclinical mechanism for ED benefit beyond cAMP PDE inhibition.

Supported by Trial 1, Trial 2

Mechanism of action

1

cAMP Phosphodiesterase Inhibition

Butea superba tuber compounds inhibit cAMP phosphodiesterase more potently than methylxanthines (caffeine, theophylline) in vitro. Elevated cAMP supports smooth muscle relaxation in cavernous bodies — a mechanism related to (but distinct from) cGMP-PDE5 inhibition by sildenafil. May explain ED benefits.

2

Androgenic / DHT-Elevating Activity

Animal and human case data document increased dihydrotestosterone (DHT) levels with Butea superba use. The mechanism is incompletely understood — it may involve LH suppression alongside direct androgenic phytochemicals or 5α-reductase modulation. The reported case showed DHT at 1512 pg/mL (vs. normal 250-990).

3

Luteinizing Hormone (LH) Reduction

Butea superba reduced LH levels in male rats, consistent with negative feedback from elevated peripheral androgens. This is a typical pattern in androgen-elevating agents and may reduce endogenous testicular function with chronic use.

4

Cavernous Smooth Muscle Relaxation

Beyond cAMP PDE inhibition, animal studies suggest direct relaxant effects on cavernous smooth muscle, supporting penile blood flow increase. This is the proximal mechanism for erectile improvement in animal models.

5

Phytoestrogen / Phytoandrogen Crosstalk

Butea superba contains both estrogenic (formononetin, flavonoid) and androgenic compounds. The net hormonal effect is androgen-dominant in standard doses. This dual-receptor activity complicates risk assessment, particularly for hormone-sensitive conditions.

Clinical trials

1
Butea superba for Erectile Dysfunction (Clinical Trial)

3-month randomized, double-blind clinical trial in Thai males with erectile dysfunction. Crude preparation of Butea superba tubers vs. placebo. Outcomes: IIEF-5 (5-item International Index of Erectile Function) questionnaire and sexual records, plus safety hematology and blood chemistry. (Cherdshewasart, Asian J Androl)

Thai male volunteers aged 30-70 with erectile dysfunction.

Significant improvement in 4 of 5 IIEF-5 questionnaire domains. Sexual record evaluation indicated 82.4% of patients reported noticeable improvement. Hematology and blood chemistry showed no apparent toxicity over 3 months. Authors concluded the plant preparation appears to improve erectile function in ED patients without apparent toxicity at the dose and duration studied.

2
Hyperandrogenemia Case Report (critical safety data)

First reported case of hyperandrogenemia due to ingestion of Butea superba supplement. 35-year-old Thai male (no underlying disease, normal prior baseline) presented with significantly increased sexual drive after taking locally-made Butea superba capsules for 'a few weeks' (initial purpose: hair loss treatment). Laboratory workup performed. (Chaiyasit, Indian J Endocrinol Metab)

Single case: Thai single male, aged 35, no underlying disease.

Dihydrotestosterone (DHT) 1512 pg/mL vs. reference range 250-990 pg/mL — significantly elevated. Other findings: DHEA-S 328 μg/dL, free testosterone 1.7%, SHBG 43.24 nmol/L. Diagnosis: hyperandrogenemia from external phytoandrogen source. **First case report establishing that Butea superba can produce clinically significant hyperandrogenemia in healthy males**. Authors noted prior literature also documented genotoxicity at large doses.

Side effects and drug interactions

Common Potential side effects

**Hyperandrogenism / DHT Elevation**: documented clinically significant increases in DHT — relevant for prostate health, hair loss (paradoxical risk despite traditional anti-hair-loss use), and acne.
Possible LH suppression with chronic use, potentially reducing endogenous testicular function.
Possible elevations in liver enzymes (AST, ALP) and increased spleen weight in animal toxicity studies at higher doses.
Possible changes in blood neutrophil/eosinophil levels at high doses.
Possible decreased serum creatinine.
Increased sexual drive/aggression (variably classified as effect or side effect).
Pregnancy and women: avoid — androgenic effects and teratogenicity concerns.
Hormone-sensitive cancers (prostate, breast): avoid.
Long-term safety beyond 3 months is poorly characterized.

Important Drug interactions

PDE5 inhibitors (sildenafil, tadalafil, vardenafil): possible additive smooth muscle relaxation — risk of hypotension and prolonged erection.
Testosterone replacement therapy: possible additive androgenic effects — monitor closely.
5α-reductase inhibitors (finasteride, dutasteride): possible antagonism — Butea may reduce these drugs' effectiveness.
Anticoagulants: theoretical interaction; clinical relevance unclear.
Hepatotoxic medications: caution given liver enzyme elevations seen in animal studies.
Hormone-sensitive cancer treatments: avoid.

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Frequently asked questions about Butea superba

What is Butea superba used for?

Butea superba is a Thai herb (often called red kwao krua) marketed for male libido, erectile function, and vitality, traditionally used as a male tonic. It is the male counterpart to the female-oriented Pueraria mirifica.

Does Butea superba help male vitality?

It is traditionally used and marketed for libido and sexual function in men, with limited human research suggesting possible benefit. Evidence is preliminary, so claims should be viewed cautiously.

How much Butea superba should I take?

Doses depend on the product; follow product labeling. It is used as a standardized root extract.

Is Butea superba safe?

Human safety data is limited. Because it may have hormonal activity, those with hormone-sensitive conditions should be cautious, and quality and sourcing vary. Check with a doctor before use, especially if on medication.

What is Butea superba?

Butea superba is a Thai herb, often called red kwao krua, marketed for male libido, erectile function, and vitality, and traditionally used as a male tonic; it is essentially the male counterpart to the female-oriented Pueraria mirifica.

What is the recommended dosage of Butea superba?

The clinically studied dose is 250-500 mg dried tuber 1-3×/day. Caution: hyperandrogenemia case report; limit duration and dose. Always follow the product label and check with a healthcare provider for personal advice.

Is Butea superba safe, and does it have side effects?

For most healthy adults, Butea superba is well tolerated at studied doses. Reported effects can include: **Hyperandrogenism / DHT Elevation**: documented clinically significant increases in DHT — relevant for prostate health, hair loss (paradoxical risk despite traditional anti-hair-loss use), and acne. It may also interact with some medications. Butea superba is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does Butea superba interact with any medications?

Possible interactions include: PDE5 inhibitors (sildenafil, tadalafil, vardenafil): possible additive smooth muscle relaxation — risk of hypotension and prolonged erection. Testosterone replacement therapy: possible additive androgenic effects — monitor closely. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for Butea superba?

NutraSmarts rates the evidence for Butea superba as Limited (2 out of 5). It is backed by 2 clinical trials and 1 cited reference summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(1 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Cherdshewasart W, Nimsakul N Clinical trial of Butea superba, an alternative herbal treatment for erectile dysfunction Asian Journal of Andrology. 2003;5(3):243-6..PubMedUsed to support: Randomized double-blind clinical trial in men with erectile dysfunction showing 82.4% of participants exhibited noticeable improvement on IIEF-5 after 3 months of Butea superba; supports Erectile Dysfunction (One Small RCT) and Traditional Thai Use for Vitality.