Comparison
Ostarine vs RAD-140
The beginner SARM vs the intermediate — what actually separates them.
Quick answer
Ostarine is the right first SARM — mild suppression, well studied, forgiving on dosing. RAD-140 is meaningfully stronger with more suppression and better strength-to-size gains. If you haven't run a SARM before, start with Ostarine and move to RAD-140 on your second cycle once you know how your body responds.
Ostarine
MK-2866, Enobosarm
Best for
First SARM cycle
Dose
10-25mg/day
Half-life
~24 hours
Suppression
Mild
PCT
Often not needed at low doses
RAD-140
Testolone
Best for
Strength and recomp
Dose
10-20mg/day
Half-life
~60 hours
Suppression
Moderate
PCT
Required
What Ostarine actually does
Ostarine is the most studied SARM in human clinical trials. It was developed by GTx for muscle wasting and osteoporosis and went through Phase II trials, giving it more human safety data than almost any other SARM. It binds androgen receptors in muscle and bone selectively, producing modest lean mass gains and significant strength improvements without the full androgenic side effect profile of steroids.
At 10-15mg/day — the beginner range — suppression is mild enough that many users recover without PCT, though bloodwork before and after is still essential. At 20-25mg the suppression becomes more meaningful and PCT is recommended. The gains are real but modest: most users report 4-6 lbs of lean mass over an 8-week cycle, which stays after the cycle ends because there's minimal water retention.
What RAD-140 actually does
RAD-140 has a significantly higher binding affinity to the androgen receptor than Ostarine, which translates directly to stronger effects — both anabolic and suppressive. Users consistently report better strength gains, more pronounced body composition changes, and a noticeable increase in aggression and drive in the gym. The half-life of ~60 hours means it accumulates in the body longer and takes more time to clear, which extends both the effects and the recovery window after your cycle.
The neuroprotective properties of RAD-140 are a genuinely interesting differentiator — early research suggests it may protect brain cells, making it one of the more scientifically interesting SARMs beyond pure physique goals. That said, it also causes the most suppression of any SARM in regular use, and PCT is non-negotiable.
Gains comparison — what to realistically expect
On Ostarine at 15-20mg/day for 8 weeks with good training and diet: 4-7 lbs lean mass, meaningful strength increase, improved recovery. Gains are keepable because they come without significant water retention.
On RAD-140 at 15mg/day for 8 weeks: 7-12 lbs lean mass, significant strength gains — users often report PRs within the first 3-4 weeks — with some water retention depending on estrogen response. The strength-to-size ratio is the best of any SARM, meaning your strength goes up faster than your weight, which matters for athletes and anyone focused on performance rather than scale weight.
Who should choose which
If: First SARM cycle, never used anything anabolic
→ Ostarine at 10-15mg/day
Lowest risk, most human data, mildest suppression. Understand how your body responds before adding complexity.
If: Second cycle, already ran Ostarine successfully
→ RAD-140 at 10-15mg/day
You know your baseline response. RAD-140 is the logical progression for meaningfully better results.
If: Strength athlete, less concerned about mass
→ RAD-140
Better strength-to-size ratio than any SARM. Used by powerlifters and combat athletes for a reason.
If: Cutting, want to preserve muscle in a deficit
→ Ostarine at 15-20mg/day
Proven for muscle preservation during caloric restriction in clinical trials. Cleaner than RAD for cutting.
PCT and bloodwork
Both suppress natural testosterone. The difference is degree. Ostarine at low doses often allows recovery without PCT — bloodwork 4 weeks after your last dose will tell you definitively. RAD-140 requires PCT regardless of dose. Standard protocol is Nolvadex (tamoxifen) 20mg/day for weeks 1-2, then 10mg/day for weeks 3-4.
Get bloodwork before starting either compound: testosterone total, free testosterone, LH, FSH, CBC, and a lipid panel at minimum. Test again 4-6 weeks after PCT ends to confirm recovery. Do not skip this step — suppression that doesn't resolve without medical intervention is a real outcome.