RAD-150 (TLD-150): The Esterified SARM Advancing Muscle Research

Introduction

Among the newest and most intriguing developments in the SARM (Selective Androgen Receptor Modulator) landscape is RAD-150, also known as TLD-150. Chemically related to RAD-140 (Testolone), RAD-150 offers a unique twist: it features an esterified structure, potentially providing a longer half-life, slower release, and sustained anabolic activity in preclinical models.

Marketed strictly for research use, RAD-150 is currently under study for its effects on:

• Muscle hypertrophy
  
• Hormonal regulation
  
• Anabolic endurance
  
• Hormone replacement alternatives
  

This blog explores what RAD-150 is, how it differs from RAD-140, the mechanisms behind its function, early data from research settings, and why it’s generating serious interest in performance, anti-aging, and muscle physiology studies.

What Is RAD-150?

RAD-150 (TLD-150) is a synthetic SARM that is chemically structured as the esterified version of RAD-140 (Testolone). By attaching a benzoate ester group to the RAD-140 molecule, researchers aim to:

• Extend its half-life
  
• Slow its metabolic breakdown
  
• Create a time-release anabolic effect
  

This esterification concept is similar to what’s done in testosterone esters (like testosterone enanthate), which are used in hormone therapy to extend action and reduce dosing frequency.

Key Attributes:

• High anabolic potential (similar to or greater than RAD-140)
  
• Enhanced stability and bioavailability
  
• Designed for extended release in vivo
  
• Non-steroidal, orally bioavailable
  

Chemical Comparison: RAD-150 vs. RAD-140

While RAD-140 delivers rapid results and strong anabolic signals, RAD-150 is designed to provide a steady, long-lasting effect for more consistent anabolic signaling over time.

How RAD-150 Works

RAD-150 functions as a selective androgen receptor modulator, binding to androgen receptors (ARs) in skeletal muscle and bone while sparing other tissues (such as the prostate or liver) from androgenic stimulation.

Mechanism Overview:

1. RAD-150 enters the bloodstream and slowly hydrolyzes into RAD-140.
   
2. The active compound binds to androgen receptors in muscle and bone.
   
3. AR activation triggers muscle protein synthesis and bone remodeling.
   
4. No conversion to estrogen or DHT—reducing common steroid-related side effects.
   

The esterified delivery system allows for extended activity, potentially reducing the frequency of dosing required to maintain stable serum levels in research settings.

Early Research Insights

Although peer-reviewed publications on RAD-150 are still limited due to its novelty, data from animal studies, in vitro research, and early laboratory use suggest the following:

1. Muscle Growth & Hypertrophy

• RAD-150 stimulates myogenic gene transcription, similar to RAD-140.
  
• Exhibits comparable anabolic response in skeletal muscle tissue.
  
• Potentially sustains elevated nitrogen retention for longer periods.
  

2. Strength and Performance

• Anecdotal and lab reports indicate:
  
  • Improved muscle fullness
    
  • Better strength retention during dieting
    
  • Possible increase in training endurance
    

These effects are attributed to consistent AR activation and steady anabolic signaling, even during extended periods between dosing.

3. Testosterone Preservation

• In animal models, RAD-140 partially preserved endogenous testosterone production compared to testosterone enanthate.
  
• RAD-150 may extend these benefits via smoother pharmacokinetics, reducing suppression spikes.
  

4. Bone Density

• In vitro models suggest increased osteoblast differentiation, pointing to potential for bone support in aging and hormone-deficient models.
  

Research Applications of RAD-150

RAD-150 holds promise in various domains of anabolic and hormone research:

A. Muscle Wasting and Cachexia

• May help preserve lean mass in calorie-restricted, aging, or disease-model animals.
  

B. Sarcopenia and Aging

• Research into testosterone alternatives for elderly or hypogonadal models.
  
• Potential long-term use models due to extended action and oral administration.
  

C. Rehabilitation and Injury Recovery

• Could assist in muscle retention during immobilization or injury-induced catabolism.
  
• Promotes lean tissue maintenance in muscle-depleting conditions.
  

D. Performance & Body Composition

• Useful in body recomposition models:
  
  • Increased lean mass
    
  • Reduced body fat
    
  • Improved endurance markers
    

E. Endocrine Function Modeling

• Hormone replacement analog in testosterone-deficient scenarios, without direct androgen replacement.
  

RAD-150 vs. Other SARMs

RAD-150’s main advantage lies in longer action, which may reduce dose frequency and smooth hormone signaling curves—especially useful in recovery or long-term studies.

Side Effects (Observed and Anticipated in Research)

While long-term data is still emerging, expected side effects are largely comparable to RAD-140, with possible improvements due to more gradual release.

Potential Side Effects:

• Mild testosterone suppression (dose-dependent)
  
• Mood or sleep disturbances (rare)
  
• Changes in cholesterol (HDL suppression)
  
• Water retention or pumps in some models
  
• No estrogenic side effects (no aromatization)
  

As with all SARMs, PCT protocols are often investigated post-cycle in preclinical settings to evaluate recovery and hormone rebalancing.

RAD-150 vs. Testosterone

RAD-150 aims to deliver testosterone-like muscle growth without the bloating, estrogen, and injection frequency associated with traditional TRT.

Dosing in Research Settings

Note: The following is based on experimental protocols and anecdotal data. This is not medical advice.

• Common preclinical doses: 10–30 mg/day (oral)
  
• Duration: 6–12 weeks for acute studies
  
• Half-life not officially published, but assumed to be longer than RAD-140
  

Because of its ester structure, RAD-150 may be studied in less frequent dosing schedules (e.g., every other day), depending on delivery and metabolism.

Stacking in Research Contexts

RAD-150 is often studied as a primary anabolic compound in combination stacks. Common research combinations include:

Stacking allows researchers to explore multi-pathway performance and recovery outcomes, but hormonal suppression may be compounded and should be monitored accordingly in experimental models.

Legal and Regulatory Status

As of 2025, RAD-150 is:

• Not FDA-approved for medical use
  
• Sold only as a research chemical
  
• Banned by WADA and other athletic governing bodies
  
• Subject to strict labeling and compliance regulations
  

Required Labeling:

“For research purposes only. Not for human or veterinary use.”

Marketing for human use or performance is illegal and may trigger regulatory action.

Summary Table: RAD-150 Snapshot

Final Thoughts

RAD-150 (TLD-150) represents an exciting new direction in SARM evolution, taking one of the most potent compounds—RAD-140—and enhancing its duration, delivery, and consistency.

By combining tissue-selective androgen activity with a prolonged-release ester structure, RAD-150 offers researchers a unique tool to study:

• Sustained muscle hypertrophy
  
• Hormonal signaling modulation
  
• Safer alternatives to anabolic steroids
  

Its oral dosing, stability, and powerful anabolic profile make it particularly attractive for longer-term studies, while its non-aromatizing action and clean metabolic profile support its use in sensitive endocrine models.

Disclaimer: RAD-150 is a research compound not approved for human use. This article is for educational purposes only and does not constitute medical advice. Always comply with all local, federal, and international regulations when handling, studying, or marketing research chemicals.

References

1. Radius Health, Inc. (RAD-140 preclinical data).
   
2. Coss, C.C., et al. (2014). “Tissue-selective anabolic effects of RAD-140.” ACS Medicinal Chemistry Letters.
   
3. Dalton, J.T., et al. (2011). “SARMs in the treatment of muscle wasting and hypogonadism.” Current Opinion in Endocrinology.
   
4. ClinicalTrials.gov – Trials related to SARMs and RAD derivatives.
   
5. WADA Prohibited List (2025).