S-23
S23
A highly potent non-steroidal SARM designed as a male hormonal contraceptive; tested only in rats, never in humans.
Legal status: Never approved or tested in humans; sold as a 'research chemical', and possession rules vary by country.
What it gives
What people use it for and what the sources report. Strength is a general category from the literature: mild, clear or strong.
Purpose
Taken for muscle, strength and a hard, lean look. In rats it built muscle and bone and cut fat, but its intended medical job was to switch off sperm production. No human studies exist.
What people seek and what studies show
Users seek muscle, strength and a dry look; every number comes from rats. There it raised lean mass and bone density and lowered fat dose-dependently, and stimulated muscle at exposures far below those that affected the prostate. The same studies show why it exists: it suppressed LH and FSH and, together with estradiol, reversibly stopped sperm production. Its effects in humans are unknown.
Effects
Evidence: Animal data only — effects in people are unproven
Sought effects by goal (as reported)
Possible side effects
Possible does not mean certain: whether they appear depends on dose, duration, individual response and monitoring. Below — what to watch for and how to notice it early.
10 possible side effects
level · how often it is reportedWhat the levels mean
Level: general category from the literature, not your personal risk
How often
- common
- reported often
- possible
- reported in some people
- rare
- reported occasionally
How to lower the risks
For 8 of 10 possible side effects there are specific ways to lower the chance: everyday measures, supplements and options a doctor may consider. For the rest — general advice. No measure removes a risk completely. Prescription medicines are listed only for a doctor to decide on, after tests — they have side effects of their own.
Check hormones before and after; if they stay low, see an endocrinologist.
How each option helps (7)
- Regular blood tests — LH, FSH and testosterone show how deep suppression is and whether natural production has recovered afterwards.
- Working with a doctor — Assesses how deep suppression is and guides recovery afterwards, including fertility testing.
- Clomiphene — A doctor may consider it after stopping, guided by hormone tests; recovery after long use can still take months. Risks: vision changes, mood swings, rare clots. Has side effects of its own.
- Human chorionic gonadotropin (hCG) — A doctor may consider it to preserve fertility (in men it keeps the testes working); it does not restart the pituitary, so natural LH still has to recover. Risks: higher estradiol, gynecomastia. Has side effects of its own.
- Tamoxifen — A doctor may consider it after steroids are stopped, guided by hormone tests; it has not been tested for this after steroid use. Risks: blood clots, vision changes. Has side effects of its own.
- Follicle-stimulating hormone (follitropins, menotropins) — A fertility doctor may consider adding it to hCG when semen tests and FSH stay low; it does not restart the pituitary. Risks: gynecomastia, acne. Has side effects of its own.
- Toremifene — A doctor may consider it after steroids are stopped, guided by hormone tests; it raised testosterone in subfertile men but was never tested after steroids. Risks: QT prolongation, clots. Has side effects of its own.
Avoid combining several oral steroids; regular cardio, soluble fiber (psyllium), less saturated fat and alcohol; if LDL/ApoB stay high, a doctor may consider a statin. Omega-3 only lowers triglycerides.
How each option helps (12)
- Regular blood tests — A lipid panel with ApoB shows how far HDL has dropped and LDL risen — changes you cannot feel.
- Working with a doctor — Interprets lipids and ApoB and decides whether a statin or other therapy is warranted.
- Avoiding alcohol and other liver stressors — Alcohol raises triglycerides; its small HDL bump does not lower heart risk.
- Regular cardio training — Raises HDL a little and lowers triglycerides; it cannot offset a steroid-driven fall in HDL on its own.
- Berberine — Placebo-controlled meta-analysis: LDL about 0.5 and triglycerides about 0.4 mmol/L lower; HDL unchanged. Trials are mostly small; no statin substitute.
- Citrus bergamot — Pooled small trials show lower LDL and triglycerides, but certainty is low to very low; it is no replacement for statins.
- Omega-3 (fish oil, EPA/DHA) — Clearly lowers triglycerides but does not fix the steroid HDL drop, the main lipid harm; DHA-containing oils may even raise LDL slightly.
- Psyllium husk fiber — Lowers LDL by about 0.2–0.3 mmol/L (roughly 5–10%), also on top of doctor-prescribed statins; no effect on HDL.
- Atorvastatin — A doctor may consider it when LDL or ApoB stay high; it strongly lowers them but barely lifts steroid-lowered HDL. Risks: muscle aches, drug interactions, rarely muscle or liver injury. Has side effects of its own.
- Rosuvastatin — A doctor may consider it when LDL or ApoB stay high; it strongly lowers them but barely lifts steroid-lowered HDL. Risks: muscle aches, rarely muscle or liver injury, slightly higher diabetes risk. Has side effects of its own.
- Ezetimibe — A doctor may consider it when LDL stays high on a statin or a statin isn't tolerated; it lowers LDL moderately but does not raise HDL. Risks: rare liver-enzyme rises. Has side effects of its own.
- Pravastatin / pitavastatin (low-interaction statins) — A doctor may consider them when LDL is high and other statins aren't tolerated; they lower LDL moderately and barely lift HDL. Risks: muscle aches, slightly higher diabetes risk. Has side effects of its own.
Products obtained without a prescription are often fake, mislabeled or non-sterile, and there is no way to check at home. For legal supplements, look for third-party testing (Informed Sport, NSF).
No alcohol, no other liver stressors, limit oral steroids and their combinations, check liver enzymes.
How each option helps (5)
- Avoiding alcohol and other liver stressors — Removes a major extra liver stressor during oral steroids and other hepatotoxic drugs.
- Regular blood tests — ALT, AST, GGT and bilirubin show liver strain before symptoms; heavy lifting alone raises AST/ALT for days, and GGT helps tell muscle from liver.
- Ademetionine (SAMe) — Used for intrahepatic cholestasis in some countries, but trials are small and of low quality; untested in steroid users. Stopping the oral steroid matters most.
- N-acetylcysteine (NAC) — Restores glutathione; proven in paracetamol poisoning and helped in early acute liver failure of other causes, but untested in steroid users.
- TUDCA (tauroursodeoxycholic acid) — Improves bile flow in cholestatic disease; in steroid cholestasis only case reports, with failures in severe cases. Stopping the oral steroid matters most.
Find the cause by tests (estradiol, prolactin, testosterone) rather than guessing.
How each option helps (1)
- Working with a doctor — Finds the cause of low libido or erectile problems instead of masking it.
What is unknown cannot be lowered, only avoided; tell your doctor what you have taken.
Stop at the first voice change and see a doctor — early stopping matters.
How each option helps (1)
- Working with a doctor — Steroid labels say to stop at the first mild signs (hoarse voice, facial hair, clitoral growth) to prevent permanent change; checks catch them early but do not make use safe.
Low-level side effects
How each option helps (1)
- Regular blood tests — Testing ends guesswork use of aromatase inhibitors — prescription drugs that can push estrogen too low and harm joints, libido, mood and lipids.
How each option helps (3)
- Adapalene — Reduces spots in many users. Redness, scaling, dryness and stinging are common early and usually ease; acne may look worse at first. Rarely, allergic swelling.
- Benzoyl peroxide — A first-line acne option. Dryness, redness and peeling are common at first; it bleaches hair and fabric; rarely, serious allergic reactions. Severe steroid acne needs a dermatologist.
- Zinc — Trials show a modest drop in inflamed spots, weaker than antibiotics; steroid acne is driven by androgens.
How each option helps (1)
- Minoxidil (topical) — Slows thinning and regrows some hair; scalp itching and early temporary shedding are common, unwanted facial hair possible. Gains fade once stopped.
Check-ups and blood tests
Which tests and check-ups to do and when. This is a guide — agree the exact schedule with your doctor.
Which doctors can help
Get medical help at once if
- Yellow skin or eyes, dark urine, pale stools, intense itching, pain under the right ribs — see a doctor now; sudden severe abdominal pain with dizziness or fainting — call emergency services.
- Deepening voice, new facial hair, clitoral enlargement — stop and see a doctor: changes can become permanent. (women)
In an emergency, call your local emergency number.
For women
Never tested in women. As one of the most potent androgen-receptor agonists, it can be expected to virilize at muscle-building doses; voice and clitoral changes can be permanent.
Myth & fact
“S-23 is just a stronger ostarine.”
It was designed as a male contraceptive: in rats it shut down sperm production. It has never been tested in humans at all.
Combinations
No specific combination notes for this substance yet. The stack check still adds up side effects that several substances share.
Sources
Possible side effects by body system, combinations, how to lower the risks and which tests to do — free.
Open the stack check