hormoneNot FDA-approvedPrescription only (US)Mesterolone (Proviron) has never held FDA approval and is not marketed as a prescription drug in the US; it has been available by prescription in some other countries for male hypogonadism and infertilityThe largest randomized trial (WHO Task Force, source 2) and a Cochrane systematic review (source 4) found no significant benefit of mesterolone over placebo on pregnancy rate for idiopathic male infertility
MesteroloneBenefits, Dosage & Interactions
Also known as: Proviron
Mesterolone, marketed under brand names like Proviron, is a synthetic androgen and anabolic steroid (AAS) that is orally active. It is derived from dihydrotestosterone (DHT) and has a chemical structure that makes it resistant to metabolic breakdown, allowing it to maintain its activity when taken orally.
Researched by DoseRoutine R&D TeamReviewed for accuracy by Nicholas Alexander, RSELast updated
Evidence: Strong — 3 human randomized trials published.
Evidence strengthStrong · 4/4
PreclinicalStrong human evidence
3 human randomized trials published.
Plasma half-life
Not established
Default unit
mg
What published protocols report
Ranges documented in the literature, shown for reference. DoseRoutine does not recommend an amount — your prescriber or the product label sets the dose.
Reported for Mesterolone in the cited sources. Published ranges are not dosing advice.
References & evidence
Documents the Mesterolone entry is written from. Each number matches an inline marker above.
- [1]Placebo-controlled trial of high-dose Mesterolone treatment of idiopathic male infertilityGerris J, Comhaire F, Hellemans P, Peeters K, Schoonjans F · Fertility and Sterility · 1991 · Peer-reviewed · PMID 1900485
- [2]Mesterolone and idiopathic male infertility: a double-blind study. World Health Organization Task Force on the Diagnosis and Treatment of InfertilityInternational Journal of Andrology · 1989 · Peer-reviewed · PMID 2680994
- [3]The effects of mesterolone on sperm count in idiopathic oligospermiaBhathena RK, Jassawalla MJ, Patel DN · International Journal of Fertility · 1987 · Peer-reviewed · PMID 2887529
- [4]Androgens versus placebo or no treatment for idiopathic oligo/asthenospermiaVandekerckhove P, Lilford R, Vail A, Hughes E · Cochrane Database of Systematic Reviews · 2000 · Peer-reviewed · PMID 10796496
How to track Mesterolone doses
Mesterolone is tracked as a protocol rather than a single reminder: a vial with a concentration, a schedule that may be titrated or cycled, and a rotation of injection sites. Here is the record that keeps all three consistent.
- 1
Record the vial and concentration
Log the vial strength and the volume of bacteriostatic water you added so Mesterolone is stored as a concentration rather than a guess. DoseRoutine converts that into mg per syringe unit and counts the doses left in the vial as you log.
- 2
Set the schedule, not just a reminder
Enter the dose in mg and the frequency. Cycled protocols get a start and end date so the history stays accurate when Mesterolone comes out of the routine.
- 3
Rotate and log the injection site
Pick the site at the moment you log the dose. The site map shows what you used last and how recently, which is the part that drifts fastest when two compounds run on different frequencies.
- 4
Log adherence, not intentions
Mark each dose taken, skipped or delayed as it happens. Weeks of honest logs are what make an adherence rate or a trend line meaningful; retrospective guessing is not.
- 5
Review against outcomes
Review Mesterolone alongside your logged metrics and any relevant blood work every few weeks before changing the dose, so the change is a response to data rather than to a good or bad day.
What to log each time
- Dose in mg and the syringe units it worked out to
- Vial: reconstitution date, concentration, doses remaining
- Injection site and time
- Any side effects in the 24 h after the dose
References & Evidence
Sources on this page that document Mesterolone dosing, timing and safety.
- [1]National Center for Biotechnology Information View source
Educational information only — not medical advice. Dose ranges vary by person, indication and prescriber.
What is Mesterolone studied for?
What is Mesterolone?Sources for this section: Jumps to this entry in the sources and references list at the end of the page.
Mesterolone, marketed under brand names like Proviron, is a synthetic androgen and anabolic steroid (AAS) that is orally active. It is derived from dihydrotestosterone (DHT) and has a chemical structure that makes it resistant to metabolic breakdown, allowing it to maintain its activity when taken orally. Unlike many other anabolic steroids, Mesterolone is not considered to be significantly anabolic for muscle building in the same way as testosterone or nandrolone derivatives. Its primary clinical uses have historically centered on androgen deficiency or male infertility, though its role in these areas has significantly diminished with newer treatment options.
In the context of performance and physique enhancement, Mesterolone is sometimes used for its anti-estrogenic properties and its ability to increase circulating free testosterone levels. It is generally not used as a primary muscle-building agent due to its relatively weak anabolic effects compared to other AAS. However, its androgenic nature means it can still contribute to virilization and other androgen-related effects.
Mesterolone is a controlled substance in many regions, including the United States, due to its potential for misuse and abuse. Its use should always be under the guidance and prescription of a qualified healthcare professional.
What does the research say about Mesterolone?
Tap a section to expand.
Mesterolone acts primarily as an androgen receptor agonist. Its chemical structure, being a 1-methylated derivative of dihydrotestosterone (DHT), makes it orally bioavailable and resistant to aromatization into estrogens by the enzyme aromatase. This resistance to aromatization is a key distinguishing feature from testosterone, which is readily converted to estradiol.
The main mechanisms of action include:
* **Androgen Receptor Binding:** Mesterolone binds to androgen receptors throughout the body, mediating typical androgenic effects. These include the development and maintenance of male secondary sexual characteristics.
* **Inhibition of Aromatase:** Although not its primary mechanism, Mesterolone has been suggested to possess some affinity for the aromatase enzyme, potentially inhibiting the conversion of androgens to estrogens. This contributes to its anti-estrogenic profile.
* **Sex Hormone-Binding Globulin (SHBG) Reduction:** Mesterolone can reduce the levels of Sex Hormone-Binding Globulin (SHBG). SHBG is a protein that binds to testosterone and other sex hormones, rendering them inactive. By reducing SHBG, Mesterolone can increase the proportion of free (bioavailable) testosterone in the bloodstream, thereby amplifying the effects of naturally produced or exogenously administered testosterone.
* **Resistance to 5-alpha reductase:** Unlike testosterone, Mesterolone is already a DHT derivative and is not significantly metabolized by the enzyme 5-alpha reductase to more potent androgens in target tissues like the prostate or skin. This means its effects are more directly tied to the parent compound's activity at the androgen receptor.
These combined actions contribute to its various physiological effects, including its modest anabolic and pronounced androgenic properties, as well as its ability to modulate sex hormone levels. (Source: DrugBank, PubChem)
Source for this section: Sources for How does Mesterolone work?: Jumps to this entry in the sources and references list at the end of the page.
Mesterolone's clinical uses have traditionally focused on conditions related to androgen deficiency, though its contemporary therapeutic applications are limited. Potential benefits, primarily observed in clinical settings or reported in historical literature, include:
* **Treatment of Androgen Deficiency:** In men experiencing symptoms of androgen deficiency (hypogonadism), Mesterolone has been used to alleviate symptoms such as reduced libido, fatigue, and decreased well-being. However, testosterone replacement therapy is now the standard for such conditions. (Source: EMA SmPC)
* **Adjunctive Treatment for Male Infertility:** Mesterolone has been explored as an adjunctive treatment for certain forms of male infertility, particularly those associated with oligozoospermia (low sperm count). It was thought to potentially improve sperm quality and quantity, though conclusive evidence of its efficacy as a primary fertility treatment is debated and more modern treatments are preferred. (Source: EMA SmPC)
* **Increased Free Testosterone Levels:** By reducing Sex Hormone-Binding Globulin (SHBG), Mesterolone can increase the concentration of free, biologically active testosterone. This can indirectly enhance the effects of endogenous or exogenous testosterone. This effect is sometimes leveraged in contexts outside of approved medical use. (Source: DrugBank)
* **Anti-Estrogenic Effects:** Due to its resistance to aromatization and potential for mild aromatase inhibition, Mesterolone can help to reduce estrogenic side effects when used alongside aromatizable anabolic steroids. This can help prevent gynecomastia and water retention. This use is primarily in non-medical contexts.
It is crucial to understand that many of these benefits are either outdated clinical applications or derived from off-label, non-medical use. For any legitimate medical concern, a licensed clinician must be consulted. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Clinical evidence regarding Mesterolone's efficacy, particularly in contemporary medicine, is somewhat limited compared to newer therapeutic agents. Most available data originates from older studies or its European marketing authorization documents (SmPC).
* **Androgen Deficiency:** The European Medicines Agency (EMA) Summary of Product Characteristics (SmPC) for Mesterolone (Proviron) indicates its use for androgen deficiency, describing it as an androgen supplement. However, it emphasizes that its use should be restricted to cases where androgen deficiency has been confirmed. (Source: EMA SmPC, various manufacturers).
* **Male Infertility/Oligozoospermia:** Some studies in the past investigated Mesterolone's role in improving sperm count and quality in men with oligozoospermia. While some reports suggested improvements, overall conclusive evidence for Mesterolone as a highly effective or first-line treatment for male infertility is generally lacking in modern reproductive medicine. Systematic reviews are scarce, and current guidelines rarely recommend it. (Source: Cochrane reviews for male infertility treatments often do not feature Mesterolone prominently as a recommended therapy).
* **SHBG Reduction and Free Testosterone Increase:** Experimental data and observations confirm that Mesterolone can significantly lower SHBG levels, thereby increasing free testosterone. This mechanism is well-established pharmacologically. (Source: PubChem, DrugBank).
* **Anti-Estrogenic Properties:** Its chemical structure provides inherent resistance to aromatization. While some suggest direct aromatase inhibition, its primary anti-estrogenic action comes from not being an estrogen precursor itself and by competing with other steroids for androgen receptor binding. (Source: DrugBank, various pharmacological texts).
It is important to note that many claims about Mesterolone's benefits, particularly in performance enhancement, are anecdotal or based on extrapolation from its pharmacological properties rather than robust, independent clinical trials for those specific indications. **Mesterolone is a controlled substance, and its use is subject to strict medical supervision.** This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
As an androgen and anabolic steroid, Mesterolone can cause a range of side effects, some of which can be significant and serious. The severity and likelihood of side effects can vary depending on the dose, duration of use, individual sensitivity, and concomitant use of other compounds. Common side effects reported include:
* **Androgenic Side Effects:** These are common due to its strong androgenic nature. They include acne, oily skin, accelerated hair loss in individuals predisposed to male pattern baldness, and increased body hair growth. (Source: EMA SmPC, PubChem)
* **Prostate Issues:** Mesterolone can stimulate prostate growth. This can lead to benign prostatic hyperplasia (BPH) or exacerbate existing prostate conditions. Regular monitoring of the prostate (e.g., PSA levels, DRE) is crucial during treatment. (Source: EMA SmPC)
* **Cardiovascular Issues:** While not significantly associated with liver strain like C17-alpha alkylated oral steroids, Mesterolone can have adverse effects on lipid profiles, potentially increasing LDL (bad) cholesterol and decreasing HDL (good) cholesterol. This can increase the risk of cardiovascular disease. (Source: DrugBank)
* **Sexual Dysfunction:** While intended to treat some forms of sexual dysfunction, paradoxically, at inappropriate doses or in sensitive individuals, it can contribute to altered libido or erectile dysfunction. Chronic suppression of natural testosterone production (if used in supraphysiological doses) can lead to hypogonadism upon cessation.
* **Psychological Effects:** Mood changes, irritability, aggression (often termed "roid rage"), and depression have been reported with androgen use. (Source: NIH NIDA on anabolic steroid abuse)
* **Liver Toxicity (Rare but Possible):** Although not C17-alpha alkylated (which is typically associated with high liver toxicity in oral steroids), prolonged or very high doses could still theoretically impact liver function, though it is generally considered less hepatotoxic than many other oral AAS. (Source: EMA SmPC notes no significant hepatotoxicity at therapeutic doses)
* **Gynecomastia (Uncommon, Indirect):** While Mesterolone itself is not aromatized, and can even help prevent gynecomastia when used with aromatizable steroids, if used in isolation and impacting the delicate hormonal balance, or if an individual has pre-existing conditions, unusual breast tissue development could theoretically occur, though this is less direct than with aromatizable steroids.
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Mesterolone use comes with several significant warnings and precautions that must be carefully considered. It is a controlled substance and should only be used under strict medical supervision and prescription. Key warnings include:
* **Prostate Cancer Risk:** Mesterolone can stimulate the growth of existing prostate cancer. It is absolutely contraindicated in men with known or suspected prostatic carcinoma. Regular prostate examinations and PSA level monitoring are essential, particularly in older men. (Source: EMA SmPC)
* **Cardiac/Renal Conditions:** Individuals with severe cardiac, renal, or hepatic disease should use Mesterolone with extreme caution, as fluid retention (edema) and worsening of underlying conditions are possible. (Source: EMA SmPC)
* **Diabetic Patients:** Mesterolone may alter glucose tolerance and antidiabetic agent requirements, necessitating careful monitoring in diabetic patients. (Source: EMA SmPC)
* **Priapism:** Sustained and painful erections (priapism) may occur. If this happens, treatment should be stopped immediately and medical attention sought to prevent permanent damage. (Source: EMA SmPC)
* **Adolescent Use:** Use in adolescent males can lead to premature epiphyseal closure, potentially stunting growth. Its use in this population is generally contraindicated or requires extreme caution. (Source: EMA SmPC)
* **Dependence and Abuse Potential:** As an anabolic steroid, Mesterolone has potential for abuse and psychological dependence, particularly in contexts of non-medical use. This can lead to serious health consequences. (Source: NIH NIDA)
* **Athletic Sanctions:** Mesterolone is a banned substance by most major sports organizations (e.g., WADA) due to its performance-enhancing properties. Athletes should be aware of stringent anti-doping regulations.
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Mesterolone is contraindicated in several situations due to the risk of serious adverse effects. These contraindications are critical and generally mean the compound should not be used in such cases:
* **Prostate Carcinoma:** Known or suspected carcinoma of the prostate gland is an absolute contraindication, as Mesterolone can stimulate the growth of malignant prostate cells. (Source: EMA SmPC)
* **Male Breast Cancer:** Patients with existing male breast cancer should not use Mesterolone. (Source: EMA SmPC)
* **Hypercalcaemia in Malignant Tumours:** Mesterolone should not be used in patients with hypercalcaemia (high calcium levels) associated with malignant tumours, as androgens can sometimes exacerbate this condition. (Source: EMA SmPC)
* **Liver Tumours (Past or Present):** Although less hepatotoxic than C17-alpha alkylated steroids, prior or existing liver tumours (benign or malignant) are a contraindication due to the potential for androgenic influence on liver cells. (Source: EMA SmPC)
* **Hypersensitivity:** Individuals with a known hypersensitivity to Mesterolone or any of its excipients. (Source: EMA SmPC)
* **Women:** Due to its potent androgenic effects and high risk of virilization, Mesterolone is generally contraindicated in women, especially pregnant or breastfeeding women. (Source: EMA SmPC)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Mixing Mesterolone with certain other medications or substances can lead to adverse interactions, increased side effects, or reduced efficacy. Always inform your healthcare provider about all medications, supplements, and illicit substances you are using.
* **Anticoagulants (e.g., Warfarin):** Mesterolone may enhance the anticoagulant effect of coumarin-type anticoagulants. This increases the risk of bleeding. Close monitoring of INR/PT is necessary, and dose adjustments of the anticoagulant may be required. (Source: EMA SmPC)
* **Corticosteroids:** Concomitant use with corticosteroids or ACTH can increase the risk of edema (fluid retention). This is particularly relevant for individuals with pre-existing cardiac or renal conditions. (Source: EMA SmPC)
* **Insulin and Oral Hypoglycemics:** Mesterolone can potentially decrease blood glucose levels. In diabetic patients, this may necessitate a reduction in the dosage of insulin or oral antidiabetic agents. Blood glucose levels should be carefully monitored. (Source: EMA SmPC)
* **Hepatotoxic Drugs:** Although Mesterolone itself is generally considered less hepatotoxic than some other oral steroids, combining it with other drugs known to cause liver damage could potentially increase stress on the liver. (Source: General pharmacological principle)
* **Other Anabolic-Androgenic Steroids (AAS):** Combining Mesterolone with other AAS, especially those that are also highly androgenic or aromatizable, can drastically increase the risk and severity of side effects, including cardiovascular strain, prostate issues, and virilization. (Source: General pharmacological principle; NIH NIDA on AAS abuse)
* **Alcohol:** Excessive alcohol consumption places stress on the liver. While Mesterolone is not C-17 alpha-alkylated, combining it with heavy alcohol intake is generally ill-advised to maintain overall liver health. (Source: General health advice)
This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Mesterolone is an orally administered medication. For any prescribed medical use, the dose and timing are user-directed and must be set by a licensed clinician based on the specific condition being treated, individual response, and overall health status.
Typically, oral medications are taken at specific intervals to maintain stable blood levels. Mesterolone has a relatively short half-life of approximately 12 hours. This would typically imply that a daily or twice-daily dosing regimen might be adopted to maintain consistent levels in the body, especially in therapeutic settings.
* **With Food:** Mesterolone can generally be taken either with or without food. However, taking it with food might sometimes reduce gastrointestinal upset for sensitive individuals. Specific clinician instructions should always be followed.
Deviation from prescribed timing or dosage can lead to reduced efficacy or an increased risk of side effects. Always adhere strictly to your clinician's instructions. This is educational information, not medical advice - consult a qualified clinician before starting, stopping or combining any compound.
Source for this section: Sources for When should you take Mesterolone?: Jumps to this entry in the sources and references list at the end of the page.
What interacts with Mesterolone?
| Interacts with | Severity | Type | What happens | What to do |
|---|---|---|---|---|
| Any peptide + hormone | Note | Category ruleConfidence: theoretical | Injectable peptides plus hormones can have overlapping or compounding effects that aren't always well characterized.Source pending | Track bloodwork with a provider; don't assume combinations are neutral. |
Frequently asked questions about Mesterolone
Mesterolone is a hormone. It is also known as Proviron. The references summarized come from NIH and PubMed records, FDA labeling where it exists, and Mayo Clinic patient material.
Mesterolone is commonly discussed in the context of supporting testosterone. Individual response varies, and use should be reviewed with a licensed clinician who can weigh the benefits and risks for your situation.
For Mesterolone, it is typically taken null. Always follow the specific dose your clinician or the product label prescribes.
Mesterolone carries potential side effects and drug interactions, documented in NIH, Mayo Clinic, and FDA label sources. Mesterolone is classified as a controlled substance in some jurisdictions, so legal status and prescribing rules apply. Stop use and contact a clinician if you experience unexpected symptoms.
As a hormone, Mesterolone can overlap with other supplements, prescription medicines, hormones and peptides. Risk depends on dose, timing and what else is taken the same day, so each pairing has to be checked rather than assumed safe. The free checker at https://doseroutine.com/interaction-checker covers Mesterolone with no sign-up.
Whether Mesterolone fits alongside testosterone replacement therapy depends on the protocol — dose, ester and ancillaries such as HCG or anastrozole — and on current bloodwork. No general contraindication applies across every TRT protocol, so confirm the combination with the prescribing clinician. See the free TRT interaction reference: https://doseroutine.com/trt-supplement-interactions
"Peptides" is not one category — healing peptides, GLP-1 agonists, growth-hormone secretagogues and melanocortins each behave differently next to Mesterolone. Check the combination peptide by peptide rather than as one group, and review it with a clinician familiar with peptide protocols.
Published frequency for Mesterolone varies by protocol and formulation, so the label or prescription is what sets it. Frequency is a clinical decision, not a fixed rule — confirm it with the prescriber or product label. Comparison of apps that keep a schedule like this: https://doseroutine.com/best-dose-tracking-apps
The effect of a missed dose of Mesterolone depends on the protocol and formulation you are on. Doubling up to "catch up" is generally not appropriate unless the label or prescriber says so. Follow the missed-dose instructions on your label or from your clinician, and log the miss so the pattern is visible later rather than forgotten.
For Mesterolone the useful record is the dose, the time it was actually taken, and what else was taken in the same window. A written log or spreadsheet works for planning but does not remind you or flag conflicts — see the honest comparison at https://doseroutine.com/vs/spreadsheet and the wider roundup at https://doseroutine.com/best-dose-tracking-apps — DoseRoutine tracks the schedule, the remaining supply and interactions with the rest of your routine in one place.
Which studies looked at Mesterolone?
Peer-reviewed research indexed in PubMed. Each entry links to the original record.
- 1.Mesterolone and idiopathic male infertility: a double-blind study. World Health Organization Task Force on the Diagnosis and Treatment of Infertility(opens PubMed in a new tab)Int J Androl · 1989 · PMID 2680994 · https://pubmed.ncbi.nlm.nih.gov/2680994/
- 2.Placebo-controlled trial of high-dose Mesterolone treatment of idiopathic male infertility(opens PubMed in a new tab)Fertil Steril · 1991 · PMID 1900485 · https://pubmed.ncbi.nlm.nih.gov/1900485/
Sources cited on this page
Specific documents referenced by the numbered markers above. Each number matches the marker in the text.
- PubChem CID 102324219(opens in a new tab)National Center for Biotechnology Information · pubchem.ncbi.nlm.nih.gov/compound/102324219
Verify at
Publisher search links for Mesterolone. These are places to check the information — they are not citations, so they are not numbered.
- DrugBank(publisher search, opens in a new tab)DrugBank Online · publisher search
- European Medicines Agency(publisher search, opens in a new tab)European Medicines Agency · publisher search
- Cochrane Library(publisher search, opens in a new tab)Cochrane · publisher search
- PubMed literature search(publisher search, opens in a new tab)National Library of Medicine · publisher search
- DailyMed labeling archive(publisher search, opens in a new tab)U.S. National Library of Medicine · publisher search
- Wikipedia entry(publisher search, opens in a new tab)Wikipedia · publisher search
DoseRoutine compiles summaries from publicly available scientific and regulatory references. Always verify important decisions with a licensed clinician. How we source and review this information.
What is the short answer on Mesterolone?
Plain-text summary, safe to quote verbatim:
Mesterolone, marketed under brand names like Proviron, is a synthetic androgen and anabolic steroid (AAS) that is orally active. It is derived from dihydrotestosterone (DHT) and has a chemical structure that makes it resistant to metabolic breakdown, allowing it to maintain its activity when taken orally.
Source: DoseRoutine — https://doseroutine.com/library/mesterolone
Cite this page
Using this in an article, AI answer, or research note? Please attribute:
DoseRoutine. (2026). Mesterolone — Overview, Benefits & Side Effects. Retrieved from https://doseroutine.com/library/mesterolone
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