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Not medical advice. The Atlas is not a substitute for a clinician who can examine you.

LGD-3303 (and ACP-105)

Lesser-known nonsteroidal SARMs (Ligand)

Evidence grade 2 of 5, Thin. Read how the Atlas grades evidence.

The written rationale for this grade is still being prepared.

FDA
Not FDA approved; preclinical only
WADA
Prohibited at all times (S1.2 Other Anabolic Agents)

Reference only. Not medical advice.

What can go wrong

Expected HPTA suppression (reduced testosterone/LH/FSH), lipid changes, and SARM-class hepatic concerns, all unquantified by human data. Products are unregulated and frequently mislabeled, an especially acute problem for obscure compounds where independent testing is scarce. Banned in WADA sport.

This is something to take to a clinician. The Atlas can tell you what is known about lgd-3303 (and acp-105) in general. It cannot tell you what is happening in your body, and the difference matters most for exactly the symptoms that bring people to this page.

LGD-3303 is a nonsteroidal SARM discovered by Ligand Pharmaceuticals (the same company behind LGD-4033), characterized preclinically for anabolic effects on muscle and bone with reduced prostate activity, including work on osteopenia in female rats. ACP-105 is a related lesser-known SARM. Both have real preclinical characterization but no human clinical trials, and both circulate in the gray market as 'research chemicals.'

The second-tier SARMs, real preclinical pedigree, zero human trials.

What people take it for

These are the reasons people give for taking it. They are not effects it has been shown to have.

  • Marketed (illegally) for lean-mass and bone support

How it is supposed to work

LGD-3303 is an orally active nonsteroidal AR agonist with anabolic activity in muscle and bone and comparatively reduced androgenic stimulation of the prostate in rat models; it has been studied in combination with a bisphosphonate for osteopenia. ACP-105 is similarly a nonsteroidal AR modulator. Like all AR agonists, both would be expected to suppress the HPT axis.

Preclinical pedigree is not human safety

LGD-3303 has a genuine pharmacology paper trail (pharmacokinetics/pharmacodynamics; osteopenic-rat combination studies), which vendors use to imply credibility. But 'characterized in rats by Ligand' is not the same as tested in humans. Neither LGD-3303 nor ACP-105 has any human safety, dosing or efficacy data.

Safety in detail

LGD-3303 and ACP-105 are unapproved drugs with no human trials. Their preclinical pedigree does not establish human safety or dosing. Self-administration carries unquantified endocrine and hepatic risk, compounded by frequent mislabeling.

Replacement is not the same as a cycle

No human dose has been validated for either compound; all consumer dosing extrapolates from rodent studies.

What it does to fertility

As AR agonists, both are expected to suppress LH/FSH and endogenous testosterone and impair spermatogenesis; human data are absent.

What has to be monitored

The bloodwork this needs, and the reason it belongs with a clinician rather than a website.

  • Total/free testosterone, LH, FSH
  • Lipid panel
  • Liver function tests
  • Hematocrit

What people get wrong

  • Often saidLGD-3303 is well-studied because Ligand published on it

    ActuallyThe studies are preclinical (rats); there are no human trials of LGD-3303 or ACP-105.

  • Often saidObscure SARMs are purer

    ActuallyObscure compounds are less independently tested, so mislabeling and contamination risk is if anything higher.

Who profits, and who pushes back

Nobody is named here yet, because we have not done that work on this entry. Read that as unfinished. Somebody almost certainly sells this, and somebody almost certainly disputes it. Assume both until we have checked.

How we got here

LGD-3303 came out of Ligand Pharmaceuticals' SARM discovery program, the same tissue-selective screening effort that produced LGD-4033, and was characterized in the late 2000s for muscle and bone effects, including osteopenia models. ACP-105 emerged from separate SARM discovery work. Neither advanced to human trials; both persist as niche gray-market compounds.

  1. 2008-2009Ligand publishes LGD-3303 pharmacology and osteopenia-model data
  2. 2010sLGD-3303 and ACP-105 appear as niche gray-market SARMs

At a glance

Discoverer
Ligand Pharmaceuticals
Best data
Preclinical (rat muscle/bone/osteopenia)
Human trials
None
Also here
ACP-105 (related minor SARM)

What this entry does not yet cover

What follows is unfinished work on our side, not a finding about LGD-3303 (and ACP-105). A short entry is not a safe entry.

  • Cost and market. We have not documented what it sells for or who sells it.
  • Supply chain. We have not mapped where it is made.
  • Who uses it. We have not documented the user groups.
  • What could change. No forward-looking summary yet.
  • How it compares. We have not set it against the alternatives.
  • Children and teenagers. We have not checked what is known about younger people.

Sources

The studies below are named and described, but not linked. You cannot open them from here and check our reading against them, which means this page is our summary of the literature rather than a document you can verify. Weigh it accordingly until the links exist.

The studies that matter

  • Vajda et al., LGD-3303 pharmacokinetics/pharmacodynamics (J Pharmacol Exp Ther)2009

    Orally active nonsteroidal SARM; anabolic in muscle with reduced prostate activity in rats

  • LGD-3303 plus bisphosphonate in osteopenic female rats2008

    Additive effects on bone; supports preclinical bone rationale