Research explainer
LGD-4033, also called ligandrol, is a nonsteroidal selective androgen receptor modulator developed by Ligand Pharmaceuticals and later licensed to Viking Therapeutics as VK5211. It binds the androgen receptor as an agonist, with potent activity in muscle and bone and partial-agonist or antagonist behaviour in the prostate. It is not approved for use anywhere.
There is exactly one published human trial of note, it is small, and it is more interesting than the summaries of it suggest. This page covers what that trial measured, where development actually stands, and the analytical problem that makes most of what is sold under this name unreliable.
Ligandrol occupies an unusual position: a compound with a real pharmaceutical development history, a genuine published clinical dataset, and a retail market that has almost nothing to do with either. Those three things are worth separating, so this page separates them.
What LGD-4033 is
LGD-4033 is a small nonsteroidal molecule that binds the androgen receptor. Unlike testosterone and its derivatives, it is not a steroid — it shares the target, not the chemical class. It acts as an androgen receptor agonist with reported tissue selectivity: potent agonist activity in muscle and bone tissue, with partial agonist or antagonist behaviour at the prostate.
Reported elimination half-life is in the region of 24 to 36 hours, which is the pharmacokinetic basis for the once-daily dosing used in its clinical programme.
The name people search for, ligandrol, is derived from Ligand Pharmaceuticals, the company that developed it. The compound was licensed to Viking Therapeutics in May 2014 and has been carried forward under the designation VK5211.
What “selective” actually means here
The selectivity in “selective androgen receptor modulator” is tissue selectivity, not receptor selectivity. There is one androgen receptor. What differs is how the receptor-ligand complex behaves once formed in different tissues — which co-regulator proteins are recruited, and therefore which genes are transcribed.
The pharmacological goal behind the whole SARM class was to separate anabolic activity in muscle and bone from androgenic activity in tissues such as the prostate. The interesting question is not whether that separation exists in a preclinical assay — it does — but how completely it holds in a whole organism over time. That is a question about systemic endocrinology, and the trial data speaks to it directly.
What the phase 1 trial showed
The reference human dataset is Basaria and colleagues, 2013: a placebo-controlled study in 76 healthy young men, run over a maximum of 21 days.
| Measure | What was reported | What it means |
|---|---|---|
| Lean body mass | Approximately 1.2 kg increase at 1 mg/day over 21 days | A real, measurable effect in three weeks — and the figure everyone quotes |
| Total testosterone | Decreased, dose-dependently | Endogenous androgen production was suppressed |
| Free testosterone | Decreased, dose-dependently | As above, the bioavailable fraction |
| Follicle-stimulating hormone | Decreased, dose-dependently | Indicates suppression at the level of the hypothalamic-pituitary axis |
| Sex hormone-binding globulin | Decreased, dose-dependently | Alters the distribution of circulating androgens |
| HDL cholesterol | Decreased, dose-dependently | An unfavourable direction for a cardiovascular risk marker |
| Triglycerides | Decreased, dose-dependently | Part of the same lipid signature |
| Liver enzymes | No elevation observed in the trial | Relevant given later case reports outside trial conditions — see below |
Read the whole table rather than the first row. A compound that adds lean mass while suppressing testosterone, FSH and SHBG and lowering HDL in three weeks is not demonstrating the clean dissociation the class was designed around. It is demonstrating a systemic endocrine effect with a measurable anabolic component. That is a genuinely interesting pharmacological result, and it is a different sentence from the one usually quoted.
Every figure above describes what was administered and measured inside a controlled clinical trial. They are reported here because the trial is the subject of this section, and they are not a protocol, a recommendation or a starting point for anything.
Note the scale too. Seventy-six subjects, all healthy young men, twenty-one days maximum. That is a phase 1 safety and pharmacokinetics study. It is not designed to answer questions about longer exposure, about other populations, or about durable outcomes, and it does not.
Where development actually stands
LGD-4033 has not been approved for human or veterinary use by the FDA or any comparable regulator. As VK5211 it has been investigated in phase 2 work directed at hip fracture recovery and muscle atrophy. The FDA classifies it as an Investigational New Drug.
This matters for interpreting anything you read about it. A compound in phase 2 has cleared initial safety screening at the doses and durations tested; it has not been shown to be safe or effective at any dose over any longer period, and that is precisely what the remaining trials exist to determine.
The problem with what is actually in the bottle
This is the section that matters most in practice, and it applies regardless of what you think of the pharmacology.
In 2017, researchers led from Brigham and Women’s Hospital purchased 44 products sold online as SARMs and analysed their contents. The results were published in JAMA.
| Finding | Products | Share |
|---|---|---|
| Contained a SARM at all | 23 of 44 | 52% |
| Amount of active compound matched the label | 18 of 44 | 41% |
| Contained the listed amount plus an unlisted compound | 3 of 44 | 7% |
| Contained no active compound at all | 4 of 44 | 9% |
Fewer than half the products contained the labelled amount of the labelled compound. Nearly one in ten contained nothing active whatsoever. Whatever the literature says about LGD-4033 as a molecule, it says nothing about the contents of an unverified vial — and a study on the molecule cannot be applied to material that has not been shown to contain it.
That is not a philosophical point. It is the reason a lot-specific Certificate of Analysis from a named laboratory, with the chromatogram attached, is the only document worth anything in this sector. A purity figure printed on a product page is a claim about a claim.
Regulatory status and reported harms
LGD-4033 is on the World Anti-Doping Agency prohibited list. It has been detected in athlete samples, including cases attributed to contaminated supplements rather than deliberate use — which is the practical consequence of the mislabelling data above.
The FDA has issued a public notification about SARM-containing bodybuilding products. Its language is direct:
“Life-threatening reactions, including liver injuries that required hospitalization, have occurred in people taking products containing SARMs.” The agency also cites increased risk of heart attack or stroke, and states that although such products are generally marketed as dietary supplements, “they are not dietary supplements. Instead, these products are unapproved drugs that FDA has not reviewed for safety and effectiveness.”
Read the original: FDA — Certain bodybuilding products put consumers at risk for heart attack, stroke, serious liver damage and moreThere is a genuine tension in the evidence worth naming rather than smoothing over. The controlled trial reported no liver enzyme elevation. Multiple case reports of hepatotoxicity have nonetheless been published in people using products obtained outside trial conditions. Both observations can be true at once, and the mislabelling data offers an obvious hypothesis for why — though a hypothesis is all it is.
What the literature does not establish
- It does not establish a safety profile beyond 21 days. The reference human trial did not run longer than that.
- It does not establish how quickly or completely suppressed endogenous hormone production recovers after longer exposure.
- It does not establish outcomes in women, in older adults, or in anyone outside the healthy-young-male trial population.
- It does not support treating LGD-4033 as a safer alternative to anabolic steroids. The trial showed hypothalamic-pituitary suppression and an adverse HDL movement in three weeks.
- It does not tell you anything about a specific vial. The JAMA analysis makes that gap quantitative.
Where this sits in our catalogue
Strate Labs does not stock LGD-4033 or ligandrol. Saying so directly is better than letting you search the catalogue for something that is not in it.
We do carry other compounds in the broader research class, including buy RAD-140 capsules and buy ostarine capsules online, with order liquid ostarine as the alternative format and a wider range of liquid research compounds for sale. The full range is on our SARMs for sale page. These are different compounds with their own literature and their own limitations — not substitutes for LGD-4033, and we are not going to present them as one.
What we would say is that the JAMA findings above are the right standard to hold any supplier to, us included. Our FAQs set out what documentation we provide before you buy anything.
Frequently asked questions
What is LGD-4033?
LGD-4033 is a nonsteroidal selective androgen receptor modulator, developed by Ligand Pharmaceuticals and licensed to Viking Therapeutics in 2014 under the designation VK5211. It binds the androgen receptor as an agonist, with potent activity reported in muscle and bone tissue and partial agonist or antagonist behaviour in the prostate. Reported elimination half-life is around 24 to 36 hours. It is not approved for human or veterinary use.
What does LGD stand for?
LGD is the internal compound prefix used by Ligand Pharmaceuticals, the company that developed it — the same origin as the common name ligandrol. LGD-4033 is the compound code; VK5211 is the designation used by Viking Therapeutics after the compound was licensed to them in May 2014.
Is ligandrol the same as LGD-4033?
Yes. Ligandrol, LGD-4033 and VK5211 all refer to the same molecule. Ligandrol is the informal name, LGD-4033 is the original developer code, and VK5211 is the designation under which it has been carried through later clinical development.
What does LGD-4033 do?
It binds and activates the androgen receptor. Because the receptor-ligand complex recruits different co-regulator proteins in different tissues, the resulting gene transcription differs by tissue — which is the basis for the class being described as selective. In the published human trial, that activity corresponded to an increase in lean body mass alongside dose-dependent decreases in total and free testosterone, follicle-stimulating hormone, sex hormone-binding globulin, HDL cholesterol and triglycerides.
Is LGD-4033 a steroid?
No. It is a nonsteroidal molecule, meaning it does not share the steroid chemical structure. It does share the target: the androgen receptor. Describing it as “not a steroid” is chemically accurate and frequently misused, because the published trial data shows suppression of endogenous hormone production and an adverse shift in HDL cholesterol within three weeks — effects associated with androgenic compounds generally, whatever their chemical class.
What did the LGD-4033 clinical trial find?
Basaria and colleagues published a placebo-controlled study in 76 healthy young men in 2013, running to a maximum of 21 days. At 1 mg per day, lean body mass increased by roughly 1.2 kg. The same study reported dose-dependent decreases in total testosterone, free testosterone, follicle-stimulating hormone, sex hormone-binding globulin, HDL cholesterol and triglycerides. No liver enzyme elevation was observed within the trial. It was a phase 1 study, so it was not designed to characterise longer exposure or durable outcomes. The dose figure describes what the trial administered under clinical supervision; it is not a recommendation.
What are the reported side effects of LGD-4033?
Within the 21-day trial, the documented effects were endocrine and lipid changes: suppression of testosterone, free testosterone, FSH and SHBG, and reductions in HDL cholesterol and triglycerides. Outside trial conditions, multiple case reports of liver injury have been published in people using products obtained commercially. The FDA has stated that life-threatening reactions including liver injuries requiring hospitalisation have occurred in people taking products containing SARMs, and cites increased risk of heart attack or stroke.
Is LGD-4033 legal?
It is not approved for human or veterinary use, and the FDA treats it as an Investigational New Drug. The FDA has stated that SARM products marketed as dietary supplements are not dietary supplements but unapproved drugs that it has not reviewed for safety and effectiveness. It is also on the World Anti-Doping Agency prohibited list, so any athlete subject to testing should treat it accordingly. Specific legal status varies by jurisdiction and is a question for a qualified adviser, not a supplier.
Are SARM products sold online accurately labelled?
Frequently not. A 2017 analysis published in JAMA tested 44 products sold online as SARMs. Only 23 of the 44 contained a SARM at all. Only 18 contained the labelled amount of the labelled active compound. Three contained the listed amount plus an unlisted compound, and four contained no active compound whatsoever. This is why a lot-specific Certificate of Analysis from a named laboratory, with the chromatogram included, is the only meaningful documentation.
Does Strate Labs sell LGD-4033?
No. We do not stock LGD-4033 or ligandrol in any format. We carry other compounds in the broader research class, including RAD-140 and ostarine in capsule and liquid formats, but those are different molecules with their own literature and we will not present them as equivalents.
How does LGD-4033 compare to RAD-140 or ostarine?
They are distinct molecules in the same broad class, each with its own binding profile, pharmacokinetics and published literature, and none of them is approved for human use. Direct head-to-head human trials do not exist, so any comparison ranking them is constructed from separate studies with different designs, populations and endpoints. Treat comparison tables in this sector with that in mind.
Are these compounds approved for human use?
No. Everything discussed here is supplied for laboratory research use only. None of it is approved by the FDA for human or veterinary use, none of it is a dietary supplement, and none of it is for consumption.
Everything discussed here is supplied for laboratory research use only. These compounds are not approved by the FDA for human or veterinary use, they are not dietary supplements, and they are not for consumption.
Both studies cited on this page are linked above and you can check them yourself — which is the standard Strate Labs would rather be held to than any claim we could make about ourselves. If you have a question this page has not answered, email support@strateslab.com.
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