SARMs

YK-11

Filed with the SARMs, and called a steroid by its own first paper

7 sections

Top of article
What it actually is
What it is supposed to do
What people take it for
The dose question
How to check you have the right molecule
What people get wrong
What is known about harm

What circulates: I found no dosing figure I could trace to a source
What was studied: Nothing in a person
How they compare: Nothing to compare against: no human dose has ever been published
As a medicine: Never an approved medicine

What it actually is

YK-11 is the odd one on this shelf: anti-doping files it among the SARMs, while the paper that introduced it in 2011 opens with the words a novel steroid compound, and its chemical name contains the steroid nucleus itself. Both readings are on the record. Nothing has been given to a person in any published study the searches behind the class page found.

What it is supposed to do

It acts on the androgen receptor as a partial agonist in cell work. The claim it is actually sold on is different: that it inhibits myostatin, the protein that limits muscle growth. That rests on a 2013 experiment in which it induced follistatin, which binds myostatin, in mouse muscle cells in a dish.

What people take it for

Muscle growth beyond what the body normally allows, on the myostatin claim. One animal study exists, in mice with bacterial sepsis, and nothing in a person turned up.

The dose question

What circulates: I found no dosing figure I could trace to a source
What was studied: Nothing in a person; Cell work in 2011, and one mouse study in bacterial sepsis

Nothing to compare against

There is nothing to compare against, because nothing has been given to a person in any published study the searches found. The myostatin claim that the selling rests on comes from a 2013 experiment in which YK-11 induced follistatin, the protein that binds myostatin, in mouse muscle cells in a dish. One animal study exists, in bacterial sepsis. The identity is genuinely contested rather than settled: anti-doping files it among the SARMs, while its founding paper opens with the words a novel steroid compound and its chemical name carries the steroid nucleus.

Reported because it is what people use. Nothing here recommends any amount.

How long it lasts

I could not find one in a person. A study exists whose full text the class page research could not reach, so the species and subject count behind it are unestablished here.

Route studied

Nothing in a person. Cell work in 2011 and 2013, and one study in mice with bacterial sepsis.

Route used

By mouth. I found no dosing figure I could trace to a source.

How to check you have the right molecule

Check whether you are being sold a SARM or a steroid, because the seller may not know. The founding paper says steroid, the anti-doping list says SARM, and this reference is not settling it. In one regulator's laboratory analysis, a product labelled as containing YK-11 was found to contain an undeclared anabolic steroid alongside it.

Walked through on two real certificates in how to read a certificate of analysis.

What people get wrong

A myostatin inhibitor is a much bigger claim than a SARM, and it is being made on cells in a dish. Follistatin rising in cultured mouse muscle cells is a long way from a person growing muscle, and the gap between those two things is where the entire selling proposition sits.

What is known about harm

No published case report names YK-11 on its own. It appears in combination cases where somebody took two or three compounds at once, and in voluntary adverse event database counts, which are reports somebody submitted rather than adjudicated findings.

Others in SARMs

The full entry

Everything on this page is a summary. Read the full entry on YK-11 for the citations, the studies, and the reasoning behind every figure above.

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