Andarine (S4)
A profile on S4, one of the earliest SARMs developed, known for its muscle hardening effects and unique vision-related side effects.
Andarine (S4)
Andarine (S4) is a Selective Androgen Receptor Modulator (SARM). It was one of the earliest SARMs investigated for the treatment of muscle wasting, osteoporosis, and benign prostatic hypertrophy (BPH).
In the bodybuilding world, it is categorized as a "hardener." It is often compared to Winstrol or Anavar in terms of the cosmetic look it provides—drying out the physique and increasing vascularity—though it is generally weaker than anabolic steroids.
Quick Specs
| Property | Value |
|---|---|
| Active Compound | Andarine (S-40503) |
| Half-Life | ~4 Hours |
| Detection Time | ~2-3 Weeks |
| Anabolic/Androgenic Ratio | Not standardized |
| Chemical Family | SARM |
| Administration | Oral (Solution/Capsule) |
Mechanism of Action
Andarine acts as a partial agonist at the androgen receptor. Ideally, it stimulates androgen receptors in muscle and bone tissue while blocking them in the prostate (which is why it was researched for prostate issues).
It helps oxidize fat and prevents the body from going catabolic while in a calorie deficit.
Pharmacokinetics & Dosing
Half-Life: ~4 Hours
Andarine has a very short half-life compared to other SARMs.
- Frequency: To maintain stable blood levels, it must be dosed 2-3 times per day (e.g., Morning, Pre-workout, Evening).
- Dosage:
- Beginner: 25mg/day.
- Advanced: 50mg - 75mg/day.
- Note: The severity of vision side effects is directly dose-dependent.
Primary Effects
1. Cosmetic Hardening
S4 is excellent for the "polished" look. It reduces water retention and increases muscle density/hardness.
2. Strength
It provides decent strength gains, though less than LGD-4033 or RAD-140.
3. Fat Loss
It has been noted to increase fat oxidation, making it a staple in cutting stacks.
Side Effects & Harm Reduction
Vision Side Effects:
The Yellow Tint: The molecule of Andarine binds to ocular receptors in the eyes. At doses usually above 50mg/day, users experience a yellow tint to their vision (sepia tone) and difficulty adjusting to darkness (night blindness). This resolves after stopping the drug, but it can be dangerous for driving at night.
1. Suppression
While milder than RAD-140, S4 is still suppressive to natural testosterone production. A mild PCT (Post Cycle Therapy) is often required.
2. Dosing Schedule
The inconvenience of dosing 3 times a day can lead to missed doses and unstable levels.
3. 5 on / 2 off Protocol
To mitigate the vision side effects, some users run S4 for 5 days on and 2 days off to allow the compound to clear the eye receptors.
Tracking Andarine
Using the Anabolic Tracker app:
- Inventory: Add Andarine (S4).
- Scheduling: Set to 3x Daily.
- Metrics: Track Vision Quality (1-10). If you notice difficulty driving at night, lower the dose immediately.
Disclaimer:
This guide is for informational purposes only. Andarine is an investigational research chemical not approved for human consumption.