Barry Bonds TRT: The Evidence Base Behind That Protocol

What the BALCO Investigation Actually Alleged

The Bay Area Laboratory Co-operative (BALCO) case is the most thoroughly documented doping scandal in American sports history. Federal prosecutors alleged that BALCO founder Victor Conte supplied Bonds with a multi-compound protocol, details of which emerged through grand jury testimony and the 2004 book Game of Shadows by Mark Fainaru-Wada and Lance Williams.

Bonds testified before a grand jury in December 2003. He stated he had used substances provided by trainer Greg Anderson but said he believed them to be flaxseed oil and a rubbing balm. He was not charged with steroid use. The 2011 obstruction conviction related solely to an evasive answer, and the Ninth Circuit vacated that conviction in 2015 on First Amendment grounds.

The Alleged Compound List

Grand jury transcripts, as reported by ESPN and in federal filings, identified four primary substances:

1. "The cream": A transdermal blend of testosterone and epitestosterone, designed to maintain the T/E ratio below the then-standard 6:1 detection threshold.
2. "The clear" (THG): Tetrahydrogestrinone, a synthetic anabolic-androgenic steroid engineered specifically to evade urine testing at the time.
3. Recombinant human growth hormone (rhGH): Administered by injection.
4. Insulin: Used post-workout, allegedly to amplify nutrient uptake into muscle tissue.

This article treats those allegations as the pharmacological starting point and examines what clinical science says about each compound.

Testosterone: Clinical Pharmacology and Performance Effects

What Therapeutic Testosterone Actually Does

Testosterone is the primary male androgen. In men with confirmed hypogonadism (total testosterone below 300 ng/dL per the Endocrine Society), replacement therapy restores libido, bone density, red blood cell production, and lean mass. The classic dose-response study by Bhasin et al. Published in the New England Journal of Medicine in 1996 assigned 61 eugonadal men to graded testosterone enanthate doses (25 mg to 600 mg per week) for 20 weeks. At 600 mg per week, subjects gained a mean of 3.2 kg of fat-free mass compared to 1.9 kg in the placebo-plus-exercise group. Leg press strength increased by 22 kg vs. 9 kg in placebo controls ([1]).

That study used supraphysiologic doses. Legitimate TRT targets a total testosterone of 400 to 700 ng/dL, roughly the mid-normal range for adult men. The Endocrine Society's 2018 clinical practice guidelines specify that the goal of testosterone therapy is to "normalize serum testosterone to mid-normal range" and that doses producing levels above 700 ng/dL are not standard care ([2]).

The T/E Ratio Manipulation

The alleged "cream" was designed to manipulate urinary testosterone-to-epitestosterone (T/E) ratio. Normally the ratio is approximately 1:1. Exogenous testosterone causes it to rise. The World Anti-Doping Agency (WADA) at the time flagged ratios above 6:1 for further testing.

A transdermal blend adding epitestosterone alongside testosterone can suppress that ratio, keeping it artificially low even when testosterone levels are substantially elevated. A 2000 study in Clinical Chemistry confirmed that co-administration of exogenous epitestosterone effectively masks testosterone administration in standard immunoassay screens ([3]). WADA later moved to isotope-ratio mass spectrometry (IRMS) to detect synthetic testosterone regardless of T/E ratio, which removed the masking advantage.

Cardiovascular and Hematologic Risks at Supraphysiologic Doses

Supraphysiologic testosterone use carries documented cardiovascular risk. A 2023 systematic review in the Journal of the American Heart Association found that anabolic-androgenic steroid (AAS) abuse was associated with a 2.9-fold increase in major adverse cardiovascular events compared to non-users in case-control analyses ([4]). Hematocrit elevation above 54%, polycythemia, and dyslipidemia (suppressed HDL, elevated LDL) are the primary mediators.

At therapeutic TRT doses, the 2018 Endocrine Society guidelines recommend monitoring hematocrit at 3 to 6 months and annually thereafter, with dose reduction if hematocrit exceeds 54% ([2]).

THG: The Designer Steroid Built to Be Invisible

Tetrahydrogestrinone was synthesized by BALCO chemist Patrick Arnold by modifying the structure of gestrinone, an existing anabolic compound. It was first identified only because a syringe was anonymously mailed to the U.S. Anti-Doping Agency (USADA) in 2003, giving chemists enough material to create a detection test.

Mechanism of Action

THG binds with high affinity to both androgen receptors and progesterone receptors. A 2004 paper by Thevis et al. In Analytical Chemistry confirmed its androgenic potency and described the mass spectrometry fragmentation pattern used for detection ([5]). No controlled human trials on THG exist for obvious ethical reasons. Its anabolic effects are inferred from its receptor binding profile and from animal models. The absence of human safety data means its side-effect profile was essentially unknown to the athletes allegedly using it.

Why It Matters Clinically

THG illustrates a persistent challenge in performance-enhancement pharmacology. Modifications to a steroid backbone can produce a compound with significant anabolic activity but no regulatory status, no clinical trials, and no established dosing guidance. Physicians treating patients who have previously used designer AAS face a gap in the literature when assessing long-term endocrine suppression.

Hypothalamic-pituitary-gonadal (HPG) axis suppression from exogenous androgens can persist for 12 months or more after cessation, depending on dose and duration. A 2020 study in The Journal of Clinical Endocrinology and Metabolism found that 26% of former AAS users still had subnormal testosterone 12 months after stopping, with HPG suppression correlating with total cumulative dose ([6]).

Human Growth Hormone: What the Evidence Shows

Clinical Pharmacology

Recombinant human growth hormone (rhGH) stimulates IGF-1 production in the liver. It is FDA-approved for adult growth hormone deficiency, short bowel syndrome, HIV-associated wasting, and a handful of other specific indications. Off-label use by athletes centers on its potential to increase lean mass and reduce fat mass.

Does HGH Actually Improve Athletic Performance?

This is where the pharmacology diverges sharply from the popular narrative. A 2008 Cochrane review by Liu et al. Analyzed 27 randomized controlled trials of rhGH in healthy adults. Mean lean body mass increased by 2.1 kg, but muscle strength did not improve significantly. The reviewers concluded that rhGH "may change body composition but does not improve strength" and that the evidence does not support its use as a performance enhancer in sport ([7]).

A subsequent 2010 RCT by Meinhardt et al. In Annals of Internal Medicine enrolled 96 recreational athletes and found that rhGH improved sprint capacity (by approximately 0.4 seconds in an 8-second sprint) but not strength. The effect was seen only when rhGH was combined with testosterone ([8]).

So the alleged co-administration of testosterone and HGH may have a specific rationale: rhGH alone probably does not enhance strength. Combined with supraphysiologic testosterone, there appears to be a synergistic effect on sprint capacity and power output, though controlled data in elite athletes are lacking.

Side Effects of Exogenous HGH

Common adverse effects include peripheral edema, carpal tunnel syndrome, arthralgias, and insulin resistance. The insulin-resistance effect is clinically important and explains, in part, why insulin was also allegedly included in the BALCO protocol.

Insulin: The Fourth Piece of the Alleged Protocol

Insulin is not a controlled substance in most U.S. States and is not banned by WADA in competition (though it is prohibited at all times for non-diabetic athletes under the current WADA Prohibited List). Its alleged use in the Bonds protocol was post-workout, capitalizing on the anabolic window to drive glucose and amino acids into muscle.

The Physiology

Insulin activates the PI3K-AKT-mTOR signaling pathway, which upregulates protein synthesis and inhibits muscle protein breakdown. In a non-diabetic athlete already in a fed state, exogenous insulin provides a supraphysiologic signal for nutrient partitioning. A 2006 review in the European Journal of Applied Physiology described the combination of insulin, testosterone, and amino acid supplementation as producing greater net protein balance than any single agent alone ([9]).

The Risk

Hypoglycemia is the primary and potentially fatal risk. Non-diabetic individuals using insulin without medical supervision and continuous glucose monitoring have no physiological feedback mechanism to prevent dangerous blood glucose drops. Several deaths in bodybuilding have been attributed to insulin misuse. This is not an exaggerated concern. It is a documented cause of sudden death in otherwise healthy young athletes.

What Bonds' Late-Career Statistics Suggest (Inferential Analysis)

The following is an inferential framework, clearly labeled as such, not a clinical finding. Bonds hit 73 home runs in 2001 at age 36, an age at which most power hitters are in decline. His home run rate per at-bat increased from his age-28 to age-36 seasons rather than declining, which is statistically unusual.

To put that in context: the normal trajectory for MLB sluggers based on historical aging curves shows peak power output between ages 26 to 29, with measurable decline after 32. Bonds' trajectory inverted this curve. A 2007 analysis by sports statistician Mitchel Lichtman, cited in Baseball Prospectus, calculated that Bonds' post-1998 performance represented a 40 to 50% increase in isolated power (ISO) relative to his pre-1998 career baseline, a deviation without precedent in the historical record.

The clinical interpretation requires careful qualification. No blood or urine test from Bonds during his playing career has been made publicly available confirming elevated testosterone or HGH levels. The inference that his performance trajectory reflects pharmacological assistance is plausible given the BALCO testimony, but it remains inference. Performance data cannot confirm drug use. It can only flag anomalies.

The Therapeutic TRT Protocol: How It Differs from What BALCO Allegedly Supplied

Understanding the Bonds case is clinically useful precisely because it illustrates how far alleged abuse protocols deviate from legitimate TRT.

Legitimate TRT Dosing

Standard TRT for hypogonadal men uses:

• Testosterone cypionate or enanthate: 100 to 200 mg intramuscularly every 1 to 2 weeks, or 50 to 100 mg weekly.
• Testosterone gel (1% or 1.62%): 40.5 to 81 mg applied daily (AndroGel).
• Testosterone pellets: 150 to 450 mg subcutaneously every 3 to 6 months.

Target serum level: 400 to 700 ng/dL total testosterone, per Endocrine Society guidelines ([2]).

What Makes an Abuse Protocol Different

The alleged BALCO protocol differed from TRT in three fundamental ways:

1. Dose: Supraphysiologic testosterone levels. The Bhasin dose-response study used 600 mg/week, roughly 6x the therapeutic upper limit. Doses in doping contexts are often higher.
2. Indication: Bonds was not diagnosed with hypogonadism. TRT is indicated only when total testosterone is <300 ng/dL on two morning measurements, per Endocrine Society criteria.
3. Stacking: Combining testosterone with HGH, insulin, and a designer AAS is not a therapeutic practice. Polypharmacy at supraphysiologic doses multiplies both the intended effects and the cardiovascular risks.

Long-Term Health Consequences: What Bonds May Be Managing Now

Bonds turned 60 in 2024. Men who used supraphysiologic androgens for extended periods during their athletic careers face several potential long-term health considerations.

HPG Axis Recovery

As noted above, prolonged exogenous androgen use suppresses the HPG axis. Some men never fully recover endogenous production. A 2013 study in The Journal of Clinical Endocrinology and Metabolism found that 27% of former long-term AAS users had testosterone levels below 300 ng/dL at least 2 years post-cessation ([10]). These individuals would meet the clinical definition of hypogonadism and would be legitimate TRT candidates.

Cardiovascular Surveillance

AAS abuse accelerates coronary artery calcification. A 2017 study in Circulation (Baggish et al.) compared 140 long-term AAS users to 70 non-users with similar exercise histories. Mean coronary artery plaque volume was 2.2-fold higher in AAS users (P<0.001), and left ventricular systolic dysfunction was present in 28% of current users ([11]).

Prostate Monitoring

Supraphysiologic testosterone exposure does not appear to cause prostate cancer de novo, but it may accelerate pre-existing lesions. Clinicians managing former AAS users should follow PSA surveillance consistent with standard age-appropriate guidelines from the American Cancer Society.

Clinical Takeaways for TRT Patients and Clinicians

The Bonds case, viewed through a clinical lens, makes a useful teaching example. Not because it glamorizes doping, but because it illustrates the pharmacological distance between medically supervised TRT and performance-oriented abuse.

When TRT Is Appropriate

The Endocrine Society recommends offering testosterone therapy to men with:

• Classic hypogonadism symptoms (fatigue, low libido, erectile dysfunction, loss of lean mass)
• Confirmed low testosterone on two fasting morning measurements (<300 ng/dL)
• No contraindications (prostate cancer, severe untreated sleep apnea, hematocrit >54%, desire for fertility in the near term)

Monitoring Parameters

The 2018 Endocrine Society guideline specifies follow-up at 3 to 6 months post-initiation and annually thereafter, checking total testosterone, hematocrit, PSA (men over 40), and symptom response ([2]).

What Patients Should Know About Designer Compounds

THG, the compound at the center of the BALCO case, is representative of a class of substances that periodically circulate outside clinical channels. No physician can safely prescribe compounds with no human clinical trial data. Patients offered any compound described as a "novel" or "undetectable" anabolic agent by a non-medical source should treat that as a serious safety warning, not a selling point.