LGD 4033 20mg/1ml LIQUID

Product status information

Chemical reagent intended exclusively for laboratory tests (Research Use Only). It is not a medicinal product, dietary supplement or food. It is not intended for use on humans or animals. Sales only to registered research units and laboratories.

WADA status – category S1.2 (other anabolic agents)

LGD-4033 (ligandrol, VK5211) is on the World Anti-Doping Agency (WADA) Prohibited List in the category S1.2 – other anabolic agents, as a selective androgen receptor modulator (SARM). The substance is prohibited in both competition and non-competition. Ligandrol is one of the most frequently detected SARMs in doping samples, and its presence has been associated with high-profile cases of anti-doping rule violations. Registered Athletes (ADAMS) must absolutely verify the current Prohibited List before any decision – the presence of Ligandrol or its metabolites in a doping sample constitutes an anti-doping rule violation.

The androgen receptor (AR) regulates muscle anabolism and bone density, but the classic androgen ligands – testosterone and anabolic-androgenic steroids – stimulate it without tissue discrimination. Muscle stimulation is then accompanied by stimulation of the prostate, skin and gonadal axis, which drives the adverse effect profile of this entire class. Selective androgen receptor modulators (SARMs) are pharmacology’s answer to this problem: molecules that were supposed to preserve the anabolic stimulation of AR in muscle and bone, while limiting activity in androgen-dependent tissues such as the prostate. LGD-4033 (ligandrol, VK5211, code Anabolicum) is one of the strongest and best clinically tested representatives of this class.

Pro-Body supplies it in line Endogenic as a research reagent in format oral solution in a 30 ml dropper bottle — the concentration of active substance (mg/ml) is declared by the COA of each batch. Chemically, it is a small non-steroidal molecule from the group of pyrrolidine-benzonitrile derivatives – not a steroid, despite a similar molecular attachment point.

In terms of mechanism, it is a tissue-selective androgen receptor ligand with high affinity: in research models it behaves as a strong AR agonist in muscle and bone, with much weaker androgenic activity in the prostate and sebaceous glands. This puts ligandrol in the group SARMs for muscle mass most frequently mentioned in androgen receptor pharmacology.

LGD-4033 was developed by the American company Ligand Pharmaceuticals, and clinical development under the code VK5211 was continued by Viking Therapeutics. Characterization of the molecule includes phase I studies (including dose-dependent increase in lean body mass) and phase II studies on regeneration after hip fracture. The strength and selectivity profile makes ligandrol one of the most frequently cited SARMs in androgen receptor pharmacology – next to ostarine (MK-2866) and testolone (RAD-140).

In research terms, ligandrol remains a model tool for studying muscle anabolism, bone metabolism and dose-dependent suppression of the gonadal axis. Purity verified by HPLC ≥98%, identity confirmed by mass spectrometry, COA available for each batch.

Regulatory status

LGD-4033 is not registered as a medicine in the EU or USA. Clinical development (phase I/II conducted by Ligand Pharmaceuticals and Viking Therapeutics as VK5211) has not been completed with a full registration program, so Ligandrol has not received FDA or EMA authorization. The FDA also issued Warning Letters against entities marketing SARMs as ingredients of human products. LGD-4033 is on the WADA Prohibited List in category S1.2 (other anabolic agents). Communicating the product as a “SARM for mass”, a “safer steroid” or an “anabolic without side effects” is contrary to the Research Use Only framework.

Selective androgen receptor modulators (SARMs) are a pharmacological class identified at the turn of the 1990s and 2000s as a response to the limitations of anabolic-androgenic steroids. The starting point was the observation that the androgen receptor functions differently in different tissues – the conformation of the ligand-receptor complex and the set of recruited coregulators (coactivators and corepressors) differ between muscle, bone, prostate and skin.

The design hypothesis assumed that a structurally appropriate molecule could stimulate AR as an agonist in some tissues (muscle, bone) and act as a partial agonist or almost inactively in others (prostate, sebaceous glands). LGD-4033 is positioned as a high potency compound in this class.

It is a non-steroidal pyrrolidine-benzonitrile derivative – a compound whose chemical skeleton has nothing in common with the sterane ring of steroids, although it binds the same receptor. In research models it shows very high affinity for the androgen receptor (Ki constant in the nanomolar range) and tissue-selective activation profile: strong anabolic agonism in skeletal muscle and bone tissue with much weaker stimulation of the prostate.

It is the combination of high anabolic power with a distinct androgenic profile that is the central feature that defines the interest in ligandrol in research. The world of pharmacology is keeping an eye on LGD-4033 for several reasons.

First, as one of the most potent SARMs with documented Phase I use in humans – with data on pharmacokinetics and dose-dependent gain in lean body mass. Secondly, as a model ligand for studying the dose-response relationship in muscle anabolism and gonadal axis suppression. Thirdly, as a tool in research on bone metabolism – a direction developed in the VK5211 program on regeneration after hip fracture. Researchers comparing individual compounds in this class will find more background in the guide, which discusses how to select the best SARMs for mass for a specific research model.

Chemically, LGD-4033 is a small non-steroidal molecule – a pyrrolidine-benzonitrile derivative that binds the androgen receptor with very high affinity.

• Common name: LGD-4033, Ligandrol, Anabolicum
• Research code: VK5211 (Viking Therapeutics development)
• Pharmacological class: non-steroidal selective androgen receptor modulator (SARM); pyrrolidine-benzonitrile derivative; tissue-selective AR ligand
• CAS number: 1165910-22-4 (in case of uncertainty – “to be verified in the batch COA”)
• Molecular formula: C₁₄H₁₂F₆N₂O (to be verified in the batch COA)
• Molar mass: ~338.25 g/mol (to be verified in the batch COA)
• AR affinity: Ki in the nanomolar range (literature context – research models)
• Laboratory of Origin: Ligand Pharmaceuticals (USA); VK5211 clinical development – Viking Therapeutics
• Delivered form: oral solution in a dropper bottle, 30 ml; concentration (mg/ml) declared in the batch COA; pharmaceutical grade ≥98% HPLC

Table of physicochemical characteristics

Origin: Pyrrolidine-benzonitrile derivatives as SARM scaffolds were created in the course of Ligand Pharmaceuticals’ work on selective androgen receptor ligands with an agonist profile in muscle and bone tissue. LGD-4033 (ligandrol) has been characterized as a compound with high AR affinity and a distinct anabolic profile in models. The molecule then entered phase I clinical trials in healthy men (e.g. Basaria et al. 2013), in which a dose-dependent increase in lean body mass and a reversible, dose-dependent reduction in testosterone and SHBG levels were observed.

Clinical development under the code VK5211 (Viking Therapeutics) was focused, among others, on: for musculoskeletal regeneration after a hip fracture.

LGD-4033 works in research models by tissue-selective binding and activation of the androgen receptor. The following axes have been described in the preclinical literature and in Phase I/II clinical trials. Pharmacological profile observed in research models:

1. High-affinity selective androgen receptor (AR) binding. The best described mechanism of ligandrol. As a non-steroidal pyrrolidine-benzonitrile derivative, the molecule binds the ligand domain of the androgen receptor with very high affinity (Ki in the nanomolar range). The conformation of the ligand-receptor complex and the set of recruited coregulators differ from those induced by testosterone, which is the molecular basis of tissue selectivity – the primary, direct effect from which the remaining observations arise.
2. Strong anabolic agonism in skeletal muscle. In Phase I clinical trials in healthy men (Basaria et al. 2013), a dose-dependent increase in lean body mass was observed after a short period of once-daily administration – literature context. This is the direction that drives most research on the anabolic profile of ligandrol and positions it among the strongest SARMs.
3. Anabolic and anti-resorption profile in bone tissue. Studies (including the VK5211 program on regeneration after hip fracture) describe the effect of ligandrol on bone metabolism – the agonist component of AR in osteoblasts and the potential to support the regeneration of bone tissue. This makes the molecule a tool in bone mineral density research alongside muscle anabolism.
4. Tissue selectivity – weaker androgenic activity in the prostate and sebaceous glands. The central defining feature of the SARM class. In research models, LGD-4033 demonstrates strong musculoskeletal anabolism with much weaker stimulation of prostate tissue and sebaceous glands than testosterone – this is the separation of the anabolic and androgenic profile for which the entire class was designed.
5. Dose-dependent suppression of the hypothalamic-pituitary-gonadal (HPG) axis. In a phase I study (Basaria et al. 2013), a dose-dependent reduction in total testosterone and SHBG levels was observed, reversible after the end of the administration period. Ligandrol is described as a SARM with a more pronounced suppression of the gonadal axis than ostarine (MK-2866) – this is a comparative observation in studies, important for the profile of this molecule.
6. No conversion to estrogens (no aromatization). As a non-steroidal pyrrolidine-benzonitrile derivative, LGD-4033 is not an aromatase substrate – it is not subject to conversion to estrogens typical of testosterone and some steroids. This distinguishes the profile of the molecule from steroid androgens at the level of hormonal metabolism.

IMPORTANT DISTINCTION

“Muscle anabolism, tissue selectivity and gonadal axis suppression” in the context of this description refers only to observations in research models (rodents, cell cultures) and phase I/II clinical trials for specific indications. This is not a guarantee or suggestion of effect in humans using the RUO reagent. The most important pharmacological distinctions: First, it concerns oral solution variant (content declared as mg/ml concentration in COA, without weighed amount) — different from the capsule variant with a standardized capsule weight; both variants contain the same molecule, but differ in the format of handling the reagent in the laboratory.

Secondly, LGD-4033 is one of the strongest SARMs with high affinity to AR, but with more pronounced suppression of the gonadal axis than ostarine (MK-2866) — a difference important for the profile of the molecule. Thirdly, LGD-4033 has a different pharmacological profile than RAD-140 (testolone) – it is a separate compound with a different skeleton and different characteristics, despite belonging to the same class.

Fourth, LGD-4033 is small molecule non-steroidal (pyrrolidine-benzonitrile derivative), not a steroid and not a peptide — binds the androgen receptor, but does not have a sterane skeleton, does not aromatize and is not a testosterone derivative.

Compound remains an investigational tool – clinical development has not been completed and the long-term safety profile has not been approved by regulatory authorities.

Understanding LGD-4033’s position in the SARM catalog and map is the focal point of this description:

• 30 ml solution variant and capsule variant — the solution variant declares the content as volumetric concentration (mg/ml) given in the COA of the batch; a bottle with a dropper makes it easier to measure the volume in methods that require handling the solution. The capsule variant contains a standardized dose of powder per capsule – it corresponds to it in the Endogenic catalog LGD-4033 in capsules. These are two formats for operating the same molecule – the choice depends on the methodology of a given research model; the identity and purity of both shall be decided by the batch COA.
• High potency and tissue selectivity — LGD-4033 is described as one of the strongest SARMs: strong muscle and bone anabolism with much weaker activity in the prostate and sebaceous glands. This combination of high potency with the resolution of the androgenic profile is driving interest in ligandrol in research.
• Ligandrol and ostarine (MK-2866) — LGD-4033 is a stronger SARM with a stronger anabolic profile in studies, but with more pronounced suppression of the gonadal axis than ostarine, which remains the SARM with the highest documented tissue selectivity and the widest clinical program. In the liquid line, the comparative equivalent is MK-2866 liquid. This distinction is central to the position of both compounds on the SARM map.
• Ligandrol and RAD-140 (testolone) — these are separate compounds with a different chemical skeleton and a different pharmacological profile, despite belonging to the same SARM class; in the liquid variant there is a separate reagent RAD-140 liquid. They should not be equated.
• Chemical class — LGD-4033 is a non-steroidal pyrrolidine-benzonitrile derivative, not an anabolic-androgenic steroid or a peptide. It binds the androgen receptor, but it does not come from testosterone, it does not have a sterane ring and it does not aromatize to estrogens.

This distinction is of both mechanistic and compliance importance: Ligandrol is sometimes mistakenly classified as a “safer steroid”, while its pharmacology (non-steroidal AR ligand with tissue selectivity) is different. In anti-doping terms, however, it remains classified by WADA as an anabolic agent (S1.2) – regardless of its non-steroidal structure and selective profile.

LGD-4033 is used in research work in several areas. In vivo models (rat, mouse) examine its effect on lean muscle mass, anabolic markers, bone mineral density and tissue selectivity towards the prostate. In vitro models measure androgen receptor affinity, agonist/antagonist profile, and coregulator recruitment in various cell lines. Specific research directions include:

• Muscle anabolism and dose-response relationship — LGD-4033 as a model SARM in studies on dose-dependent increase in lean body mass and anabolic markers (phase I direction, Basaria et al. 2013)
• Metabolism and bone density — analysis of the anabolic-anti-resorption profile in bone tissue, including the direction of regeneration after a hip fracture (VK5211 program)
• Tissue selectivity of AR ligands — ligandrol in studies on the separation of muscle-bone anabolism from androgenic activity in the prostate and sebaceous glands
• Gonadal axis suppression — analysis of the dose-dependent effect on the hypothalamic-pituitary-gonadal axis and the reversibility of this effect
• Comparative pharmacology of SARMs — LGD-4033 in analyzes with MK-2866 and RAD-140 in terms of anabolism potency, selectivity and effect on the gonadal axis; in the liquid line, stronger compounds are also used for such combinations, e.g. S-23 liquid
• Detection methods in anti-doping analysis — Ligandrol as an analyte in the development of SARM detection methods for WADA control

LGD-4033 (ligandrol, Anabolicum, VK5211; 30 ml oral solution with dropper) is a non-steroidal selective androgen receptor modulator (SARM) from the group of pyrrolidine-benzonitrile derivatives, developed by Ligand Pharmaceuticals and clinically developed by Viking Therapeutics (phase I/II). This is one of the strongest and best clinically tested SARMs. Its central mechanism is high-affinity tissue-selective androgen receptor binding (Ki in the nanomolar range): strong anabolic agonism in muscle and bone with much weaker androgenic activity in the prostate and sebaceous glands.

Phase I studies (Basaria et al. 2013) described a dose-dependent increase in lean body mass and a reversible, dose-dependent suppression of the gonadal axis (reduction in testosterone and SHBG). LGD-4033 is a small molecule non-steroidal, not a steroid and not a peptide, with a more pronounced suppression of the gonadal axis than ostarine (MK-2866) and a different profile than RAD-140 (testolone).

The 30 ml solution variant (concentration mg/ml in COA) differs in format from the capsule variant. HPLC purity ≥98%, MS Q-TOF, COA for each batch. Regulatory Status – Research Use Only; lack of EMA/FDA/EFSA authorization (clinical development not completed); WADA Prohibited List, Category S1.2 (other anabolic agents).

The broader context of selecting and comparing compounds of this class in terms of anabolic profile is discussed in the guide on how to choose SARMs for bodybuilders; The full range of reagents in liquid form is available in the category SARMs liquid.

1. Basaria S, Collins L, Dillon EL, Orwoll K, Storer TW, et al. (2013). The safety, pharmacokinetics, and effects of LGD-4033, a novel nonsteroidal oral, selective androgen receptor modulator, in healthy young men. PubMed
2. Solomon ZJ, Mirabal JR, Mazur DJ, et al. (2019). Selective Androgen Receptor Modulators: Current Knowledge and Clinical Applications. PubMed
3. Narayanan R, Coss CC, Dalton JT (2018). Development of selective androgen receptor modulators (SARMs). PubMed
4. Wagener F, Guddat S, Görgens C, Thevis M, et al. (2022). Investigations into the elimination profiles and metabolite ratios of micro-dosed selective androgen receptor modulator LGD-4033 for doping control purposes. PubMed