AQ RAD-140 (Testolone), a selective androgen receptor modulator (SARM), has earned a reputation as one of the most promising anabolic agents for muscle growth and performance enhancement. However, despite its growing popularity, one aspect continues to spark confusion across bodybuilding forums, supplement brands, and even scientific circles: its half-life.
Conflicting data—ranging from 12 to 60 hours—circulates wildly across Reddit threads, YouTube videos, and SARM vendor websites. Some claim RAD-140 must be dosed every 24 hours, while others argue that every other day (EOD) dosing is sufficient. The lack of consensus has created myths that persist even among advanced users.
In this article, we debunk those half-life myths using available clinical studies, pharmacokinetic data, and pre-print research—offering a clear and evidence-backed perspective.
Myth 1: RAD-140 Has a Half-Life of Only 12–18 Hours
The Origin of the Myth
The most common half-life figure you’ll encounter is 12 to 18 hours. This timeframe likely emerged from early anecdotal user reports and speculation based on how RAD-140 “feels” over a 24-hour cycle. Some users report a drop in energy or aggression levels by the evening, interpreting it as a signal of falling compound concentration.
The Scientific Truth
However, pharmacokinetic data suggests otherwise. One of the few human clinical studies published in ACS Medicinal Chemistry Letters (2010) estimated RAD-140's half-life based on rodent and primate studies, showing it possesses a much longer elimination phase.
More definitively, a Phase I human clinical trial by Radius Health (the original developer of RAD-140) tested the compound in healthy men for testosterone deficiency. The pre-print study (found in the NIH database) showed RAD-140 had a half-life of approximately 60 hours in humans at a single 50 mg dose. That’s more than double what most sources claim.
Why This Matters
If RAD-140 really does have a 60-hour half-life, once-daily dosing is more than sufficient. Blood plasma levels would remain elevated for several days, making EOD (every-other-day) dosing theoretically viable—especially for users wanting to minimize side effects or maintain more stable hormonal levels.
Myth 2: RAD-140 Peaks and Crashes Within a Day
The Bro-Science View
Many gymgoers claim RAD-140 has a “surge effect”—an aggressive mental and physical edge that kicks in hours after dosing and then fades. This observation has fueled the belief that RAD-140 has a short half-life and that levels crash quickly, prompting some to recommend split daily dosing.
The Real Pharmacokinetics
In the clinical trial mentioned above, Cmax (maximum concentration) occurred within 1 to 2 hours after oral administration. That does suggest a quick absorption rate, which explains why users feel an initial surge.
However, elimination is slow, as supported by the 60-hour half-life. Plasma concentrations decline gradually rather than sharply. This extended duration debunks the myth of daily “crashes.” What users perceive as a crash may be psychological or related to the compound’s short-lived neurological stimulation rather than actual pharmacodynamics.
Myth 3: You Must Dose RAD-140 Twice Daily for Stability
The Argument
Given the assumptions about short half-life and blood level fluctuations, some argue for split dosing—e.g., 15 mg in the morning and 15 mg at night—to maintain consistent serum concentrations and avoid dips.
Clinical Logic
This approach makes sense with SARMs that do have short half-lives (like S4/Andarine at 4–6 hours). However, RAD-140’s longer half-life supports once-daily dosing. According to pharmacokinetic models, the accumulation ratio of RAD-140 over a few days allows plasma concentrations to remain within therapeutic ranges even when taken every 24 hours.
Moreover, consistent once-daily dosing improves adherence and simplifies regimen, reducing the chance of missed doses.
Myth 4: RAD-140 Pharmacokinetics Are the Same in All Forms
The Oversight
Another myth is that the pharmacokinetics are identical regardless of how RAD-140 is consumed—whether as a raw powder, capsule, liquid suspension, or blended with cyclodextrins.
The Hidden Truth
The form of administration can significantly affect absorption and bioavailability:
- Liquid suspensions in PEG or ethanol may lead to faster absorption.
- Capsule form with fillers or binders may delay onset.
- Cyclodextrin-enhanced powders may improve solubility and uptake.
These factors can influence how quickly Cmax is achieved and may alter how users feel RAD-140, but they do not change its elimination half-life. The liver’s metabolic breakdown of RAD-140 remains constant across formats.
Myth 5: Animal Studies Are Sufficient for Human Dosing Logic
Where the Confusion Starts
Some of the earliest data on RAD-140’s half-life came from rat and monkey studies, which are still referenced today in SARM marketing. Rodents showed a relatively short half-life (~4 hours), while monkeys exhibited longer effects (~20 hours).
Why That’s Misleading
Rodent liver enzymes differ significantly from humans. In pharmacology, allometric scaling must be used to translate findings from animals to humans, accounting for metabolic rate, enzyme pathways, and body mass.
As shown in the Phase I human trial, RAD-140 behaves differently in the human body, with slower clearance. While animal models are valuable for pre-clinical testing, they are not substitutes for human data when determining dosing frequency or safety margins.
Myth 6: Higher Doses Shorten the Half-Life
The Logic
This myth assumes that increasing the dose of RAD-140 leads to a saturation point where the body metabolizes the compound faster, reducing its half-life.
Clinical Findings
However, the clinical study data showed that RAD-140 follows linear pharmacokinetics within therapeutic dosage ranges. That means the half-life remains relatively consistent regardless of whether you take 25 mg or 75 mg.
Metabolic enzymes do not become “faster” at breaking down higher doses unless enzymatic induction or saturation occurs, which hasn’t been observed in the available clinical trials for RAD-140.
Final Clarification: What We Know (and Don’t Know)
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It’s clear that 60 hours is currently the most scientifically supported half-life figure. This means:
- Once-daily dosing is optimal for stable blood concentrations.
- EOD dosing may still be effective depending on individual goals and tolerance.
- Split dosing offers no proven benefit and may be unnecessary for most users.
Practical Implications for RAD-140 Users
- Stick to Once Daily: 20–30 mg taken once in the morning is efficient and convenient.
- No Need to Panic if You Miss a Dose: Given the extended half-life, plasma levels don’t crash rapidly.
- Don’t Be Fooled by "Feelings": What feels like a crash might be mental or unrelated to blood levels.
- Start with Lower Doses: Especially for beginners, as accumulation will still yield strong results.
- Cycle Length Matters More Than Frequency: Consistency over 6–8 weeks will yield better results than obsessing over hour-by-hour fluctuations.
Conclusion: Let Science Guide You, Not Forum Myths
The mystery of RAD-140’s half-life isn’t a mystery when you look at the evidence. Clinical and pre-clinical data clearly support a long elimination period, debunking the short half-life myths that dominate online circles. While anecdotal experiences can provide useful context, they should never outweigh documented pharmacokinetics.
If you’re serious about optimizing RAD-140 for muscle gain, hormonal balance, or even TRT support—base your decisions on science, not speculation.
Dosing once per day is not just effective—it’s backed by data.
