S23 | S-23 SARM Solution 20mg/ml – 50ml
| Application | Selective Androgen Receptor Modulator (SARM) |
| Concentration | 2% (20mg/ml) |
| Composition | 98% PEG400, 2% S-23 (>99% purity) |
| CAS | 1010396-29-8 |
| Molar Mass | 416.77 g/mol |
| Chemical Formula | C18H13ClF4N2O3 |
| Synonyms | S-23, S23 |
| Storage | Minimize open air exposure, store in a cool dry place |
| Terms | For laboratory research use only. Not for human or animal consumption. |
What Is S-23?
S-23 is a non-steroidal selective androgen receptor modulator (SARM) developed by GTX Inc. as a potential male hormonal contraceptive. It is one of the most androgenically potent SARMs characterized, with high binding affinity for the androgen receptor and near-complete suppression of LH and FSH at higher doses in animal models — a profile that makes it uniquely interesting for both contraception research and comparative pharmacology studies at the strong end of the SARM potency spectrum.
Unlike partial agonists such as Ostarine (MK-2866), S-23 acts as a full AR agonist in most tissues, producing robust anabolic responses in muscle and bone while also demonstrating significant androgenic activity in reproductive tissues. This places S-23 at the opposite end of the SARM selectivity spectrum from Ostarine, making them natural comparative tools in receptor selectivity research.
Mechanism of Action
S-23 binds the androgen receptor with very high affinity and acts as a full agonist in muscle and bone. Its high tissue penetration and strong receptor engagement produce potent anabolic effects alongside significant HPG axis suppression — including near-total suppression of FSH and LH in rat models, leading to infertility via reduced sperm production. Critically, this suppression is reversible upon cessation, which is a prerequisite for any contraceptive application. S-23 has been studied alongside progestins in male contraceptive animal models to examine combination regimens.
Research Applications
- Male hormonal contraception: Near-complete spermatogenesis suppression via FSH/LH suppression, with reversibility upon cessation.
- SARM potency benchmarking: Used as the high-affinity, high-androgenicity reference point in comparative SARM panels.
- Muscle and bone anabolism: Dose-dependent lean mass and bone mineral density effects characterized in rodent models.
- AR pharmacology: Full agonist at both muscle/bone and androgenic tissues — useful for studying the limits of tissue selectivity.
Related Research Compounds
S-23 is positioned at the high-androgenicity end of the SARM spectrum. Its contrasting selectivity profile compared to Andarine (S4) and Ostarine makes it valuable in selectivity studies alongside RAD-140 and LGD-4033. For dual-mechanism anabolic studies, it is sometimes combined with MK-677 (Ibutamoren).
For laboratory research use only. Not for human or animal consumption.
Reviews
There are no reviews yet.