Description
PrymaLab · Research use only
S4 (Andarine) (25mg/capsule) 60 Capsules
Andarine, one of the first aryl-propionamide SARMs, 25 mg in each of 60 capsules
S4, also called andarine, is one of the first nonsteroidal selective androgen receptor modulators (SARMs) shown to act selectively in animals, an aryl-propionamide described in 2003. It is a small molecule, not a peptide. This listing is a bottle of 60 hard gelatin capsules, each holding 25 mg of andarine blended with microcrystalline cellulose. Its literature is preclinical: receptor binding and reporter assays, castrated-rat studies of tissue selectivity, and a bone study in ovariectomised rats.
Specifications
| Property | Value |
|---|---|
| Compound | Andarine (S-4), selective androgen receptor modulator |
| CAS number | 401900-40-1 |
| Molecular formula | C19H18F3N3O6 |
| Contents | Andarine: 25 mg per capsule |
| Form | Hard gelatin capsules containing the active substance blended with microcrystalline cellulose, packed in a sealed bottle |
| Storage, sealed | Store at room temperature (15–25 °C) in the tightly closed original container, dry and protected from light |
| Safety data sheet | PL-SDS-011 |
What is in each capsule
Each capsule carries 25 mg of andarine, which the safety data sheet puts at about 6.2% of the capsule contents by weight. The rest of the fill is microcrystalline cellulose, inside a gelatin shell, and a bottle holds 60. Andarine is classified as a serious eye irritant (H319) and as suspected of damaging fertility or the unborn child (H361); the filler and shell are not classified. The sheet asks for the bottle to be stored locked up, tightly closed in its original container at 15 to 25 °C, dry and out of the light.
What the research covers
Among the first active SARMs
In 2003 Yin and colleagues examined four chiral, nonsteroidal compounds from their laboratory, which bound the androgen receptor with Ki values from 4 to 37 nM1. Only two, S-1 and S-4, worked in castrated rats, where the weights of the prostate and seminal vesicles measured androgenic activity and the weight of the levator ani muscle measured anabolic activity1. Both acted more on the anabolic organ than on the androgenic ones: they were less potent and less effective than testosterone propionate on the prostate and seminal vesicles, but similar to it or stronger on the levator ani1. Near their half-maximal effective levels, neither caused significant suppression of LH or FSH1. The authors called them the first members of a new class of SARMs with selective anabolic effects1.
Bone in ovariectomised rats
Kearbey and colleagues then studied S-4 in 120 female rats in twelve groups, starting at ovariectomy, a model of accelerated bone loss, and continuing for 120 days2. S-4 maintained whole-body and trabecular bone mineral density and cortical content, increased the strength of excised femurs in biomechanical tests, and lowered body fat2. The authors proposed that a SARM could reduce fractures both through bone and by preventing falls through stronger muscles, though falls and strength were not what this study measured2.
What is not established
Everything here is rat work from one research group. Why S-4 favoured the levator ani over the prostate was not settled either: a 2007 review listed tissue distribution, tissue-specific 5α-reductase, ligand-specific gene regulation and tissue-specific coactivators as mechanisms that still had to be sorted out3. No controlled human study of andarine appears in the references, and none of the studies used capsules. The guide to SARMs versus peptides compares the class with the peptides PrymaLab sells.
How each lot is tested
Every lot is tested in PrymaLab’s own laboratory in Ashland, Kentucky before release. Published certificates are listed on the results page and can be checked by number and key on the verify page. These are in-house results from PrymaLab Analytical, not an independent test, and the lab is not accredited to ISO 17025. The third-party testing guarantee on this page still applies: if any independent laboratory finds the wrong compound, or less than the stated purity or amount, the order is refunded and the cost of the test is reimbursed.
Frequently asked questions
Is andarine the same compound as S-23?
No. Both are nonsteroidal aryl-propionamide SARMs and share a general framework, but they are different molecules with different formulas and CAS numbers. Their published work also differs: andarine was studied for tissue selectivity and bone, S-23 as a male contraceptive in rats.
What did the castrated-rat studies measure?
Prostate and seminal vesicle weight as markers of androgenic action, and levator ani muscle weight as a marker of anabolic action, each compared with testosterone propionate. A compound that moves the second more than the first is called tissue-selective. These are rat organ weights, not measures of function.
How should the bottle be stored?
Locked up, as the safety data sheet asks, and tightly closed in the original container at 15 to 25 °C, dry and away from light. The capsules need no refrigeration. Andarine is an eye irritant and a suspected reproductive toxicant, which matters most when capsules are opened.
Has andarine been tested in people?
Not in any study cited here. Andarine is an experimental compound known from rat studies, and it is neither a medicine nor a supplement. PrymaLab sells it for laboratory research only, and the capsules must not be swallowed by or given to people or animals.
References
- Yin D, Gao W, Kearbey JD, et al. Pharmacodynamics of selective androgen receptor modulators. J Pharmacol Exp Ther. 2003;304(3):1334-40. DOI · PubMed
- Kearbey JD, Gao W, Narayanan R, et al. Selective Androgen Receptor Modulator (SARM) treatment prevents bone loss and reduces body fat in ovariectomized rats. Pharm Res. 2007;24(2):328-35. DOI · PubMed
- Gao W, Dalton JT. Expanding the therapeutic use of androgens via selective androgen receptor modulators (SARMs). Drug Discov Today. 2007;12(5-6):241-8. DOI · PubMed
Research use only
For laboratory research use only. S4 (Andarine) (25mg/capsule) 60 Capsules is not a drug, food, cosmetic or dietary supplement, is not approved by the FDA or any comparable authority for human or veterinary use, and must not be given to people or animals. It is sold to qualified researchers and institutions, and the buyer is responsible for lawful handling and disposal.
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