Y-134

guinea pig

Also seen as: Y134, Y 134

The Dose Guy’s verdict

Oct 27, 2026
1 source

Run raloxifene instead. Y-134 is a research SERM with one cell-and-rat paper behind it and no human data at all, now sold for gyno and estrogen control. Raloxifene does that exact job with human receipts, a known dose, and a known side profile, and it costs less. The only argument for Y-134 is a rat study where it beat raloxifene on mammary tissue, and a rat’s mammary gland is not your chest.

Would I take it?Caution. Raloxifene already does this.

What it is

A SERM, meaning it sits on estrogen receptors and blocks or activates them depending on the tissue, without lowering estrogen in your blood. Researchers built Y-134 from the core structure of raloxifene while hunting for a better breast cancer drug, and it never left the lab. It reaches the gym crowd as a research chemical, pitched as a stronger raloxifene for shrinking gyno.

That pitch skips two things. A SERM does nothing for bloat or the other blood-estrogen problems, which is an aromatase inhibitor job like exemestane. And raloxifene and tamoxifen already cover the receptor-blocking side with decades of people behind them.

What the research shows

No human trials. Zero. Everything below is animal or in-vitro work. Read it as “interesting,” not “evidence it works in you.”

One paper, from 2007. Receptors, cancer cells, and rats. That is the whole file:

Y-134 blocked both estrogen receptor alpha and beta in transfected cells, with estimated IC50s of 0.52 nM and 2.94 nM, and suppressed estrogen-driven growth of MCF-7 and T47D breast cancer cells. A dish, not a person.Br J Pharmacol 2007 · cell assays

At the same dose as raloxifene, Y-134 was better at stopping estrogen-driven terminal end bud outgrowth and DNA synthesis in rat mammary glands, and about the same on the uterus. This is the result the gyno pitch rests on.Br J Pharmacol 2007 · ovariectomized rats

No human trial, no human pharmacokinetics, no human safety data. Nobody has measured how much reaches your blood or how long it stays.as of Oct 2026

Realistic protocols

I’m not building a protocol out of one rat paper. Nobody knows the human dose, so any number on a label is a guess dressed as a protocol, and the few logs out there mostly copy raloxifene’s daily rhythm without knowing whether Y-134 lasts the same in a person. If gyno is the problem, run raloxifene at the standard 60 mg a day, with a sensitive estradiol test so you know what you are treating. It is not a PCT drug either: nobody has checked what Y-134 does to your LH and testosterone, and restarting is tamoxifen’s or enclomiphene’s job. If you run it anyway, get the bottle tested by an independent lab first, since a compound this obscure is easy to fake, then go low, go short, log everything, and stop at the first sign of leg pain or swelling.

Side effects

No side effect has ever been measured in a human, so this is class logic:

unknownRaloxifene, its parent, carries a blood clot signal. Assume Y-134 does too until someone proves otherwise, and treat a swollen, painful calf as an emergency.

Where to buy

Disguised Research–

$89.99 / unit

✓ verified Oct 31

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