Andarine (S-4)
Also known as: Andarine, S-4, S4, GTx-007, Acetamidoxolutamide
The SARM with a side effect no other compound has: a yellow tint over everything you see, because it binds receptors in the retina.
Substance family
Non-steroidal compounds binding the same androgen receptor as testosterone, but favouring muscle and bone over prostate and hair. The selectivity is real; the suppression of the body's own production is not avoided by it. None is approved anywhere.
Effects on
Which outcomes this substance acts on — descriptive, not a recommendation.
Strain profile
Where this substance is most likely to hit — a rough orientation, individually dependent on dose, duration and predisposition.
This substance causes
Dosing & protocols by goal
Rough orientation ranges as reported in harm-reduction literature — not an individual treatment plan. Doses are individual and open-ended; frequency depends on the ester or half-life.
Clinical research (dose range studied)
MedicalDose
Investigated in early trials only
Frequency
—
Cycle length
—
Development was discontinued at an early stage, in part because of the visual effects. There is no approved dose and no phase 3 data.
Grey market practice
IntermediateDose
25–50 mg / day
Frequency
Split into 2–3 doses
Cycle length
6–8 weeks
The short half-lifehalf-lifeHow long it takes for half the substance to leave the body — it determines dosing frequency, not duration of effect. of around 4 hours is why it is split — a single daily dose produces peaks and troughs. Visual effects scale directly with the dose and appear reliably above roughly 50 mg.
Higher doses
Not a recommendationDose
> 75 mg / day
Frequency
—
Cycle length
—
Visual disturbance becomes near-universal and suppressionsuppressionThe body shutting down its own testosterone production because an external source is present. matches that of a mild steroid, while the muscle effect does not scale in proportion.
Side effect & countermeasure
Typical problems and what you can do to reduce harm — at a glance. Does not replace medical monitoring.
Problem
Visual disturbance — a yellow tint and poor night vision
Countermeasure
Unique to this compound and the reason its development stopped. Andarine binds receptors in the retina, producing a yellowish cast over the visual field and difficulty adapting from light to dark. It is dose-dependent, worst at night, and reported to resolve within days to weeks of stopping. It has not been studied long enough to state that resolution is guaranteed, which is the actual problem: nobody knows what repeated cycles do to the retina.
Problem
Suppression of the body's own production
Countermeasure
The 'selective' in SARMSARMA non-steroidal compound that binds the androgen receptor with claimed tissue selectivity. does not mean the axis is spared. Andarine suppresses LH and FSH measurably at the doses used, and recovery takes weeks. Bloodwork before and after, and a PCTPCTThe protocol after a cycle intended to restart the body's own testosterone production. plan, belong here as much as with a steroid — enclomiphene or tamoxifen are the tools.
Problem
Falling HDL
Countermeasure
As with the other oral SARMsSARMsA non-steroidal compound that binds the androgen receptor with claimed tissue selectivity., HDLHDLThe lipoprotein that carries cholesterol away from artery walls — suppressed hard by oral steroids. drops. Cardio, omega-3 and citrus bergamot soften it; a lipid panel before and during turns this from a guess into a decision.
Problem
Driving and operating machinery
Countermeasure
Worth stating plainly because it is a practical safety issue rather than a lab value. Impaired dark adaptation makes night driving genuinely dangerous, and the effect builds over the cycle rather than announcing itself on day one.
Problem
There is no quality control
Countermeasure
Sold as a research chemical, andarine has no manufacturing oversight. Analyses of grey market SARMsSARMsA non-steroidal compound that binds the androgen receptor with claimed tissue selectivity. repeatedly find wrong compounds, wrong doses or nothing at all. Third-party testing is the only partial answer, and it is not a guarantee.
Overview
Andarine is one of the earliest SARMs and the one with the most distinctive side effect in this entire category: it changes what you see.
That is not a rumour or a rare reaction. It is a predictable, dose-dependent consequence of how the molecule interacts with tissue in the eye, it was documented during clinical development, and it contributed to that development being abandoned.
Mechanism of Action
Like other SARMs, andarine binds the androgen receptor without a steroid backbone, with preferential activity in muscle and bone over prostate. The intended profile was anabolic effect with fewer androgenic consequences.
The problem is that receptor selectivity across tissues is not as clean as the name suggests. Androgen receptors exist in the retina, and andarine binds them there too. The result is a yellow-green tint over the visual field and impaired adaptation from bright to dark conditions.
The short half-life of roughly four hours means blood levels swing considerably on once-daily dosing, which is why users split it — and why the visual effects are often most noticeable at peak concentration.
The Visual Effect, Honestly
Descriptions are consistent: a yellowish cast over everything, most obvious against white surfaces and bright light, along with a noticeably longer time for the eyes to adjust when moving into darkness.
It appears dose-dependently, is more pronounced at higher doses, and reports indicate it resolves over days to weeks after stopping.
The part worth being careful about is what is not known. There is no long-term data on repeated exposure. Nobody has followed a group of people through several andarine cycles to see whether retinal function fully recovers each time. The reassurance that "it goes away" comes from user reports over short periods, not from studies.
For a substance whose only real advantage over a mild steroid is convenience, accepting an unstudied effect on the retina is a poor trade.
Where It Sits Against the Others
Compared with ostarine, andarine is more androgenic and more suppressive, with a stronger effect on strength and a drier look often reported. Compared with LGD-4033 it is weaker for mass.
That places it in an awkward spot: not the mildest option, not the strongest, and the only one that affects your vision. The people who use it generally do so for the hardening effect in a cut, which drostanolone achieves without touching the eyes.
Side Effects & Risks
- Yellow tint over the visual field and impaired night vision
- Suppression of the body's own testosterone production
- Falling HDL, rising LDL
- Elevated liver values in some users
- Fatigue and low mood, largely downstream of suppression
- No manufacturing oversight; contamination and mislabelling are common
Blood Work & Monitoring
- Total and free testosterone, LH, FSH — before, during and after; suppression is real
- Lipid profile (LDL, HDL, triglycerides)
- Liver values (ALT, AST, GGT)
- Estradiol (sensitive assay) — SARMs do not aromatise, so estradiol falls with suppressed testosterone
- Vision cannot be monitored with a blood test — the effect is the signal, and it means stop
Legal status by region
Regulation differs considerably between jurisdictions and changes over time. This is a rough orientation, not legal advice — check the rules that apply where you are.
| Region | Regulatory status |
|---|---|
| United States | Not approved; FDA warning issuedThe FDA has published explicit warnings about SARMs sold as supplements. |
| EU / UK | No marketing authorisationNeither a medicine nor a supplement — no legal route for human use. |
| Most other jurisdictions | Unregulated grey areaPossession is legal in many places because no framework covers it. That is not an indication of safety. |
| Competitive sport | Prohibited at all timesListed by WADA under S1.2. |