WHAT IS ANDARINE? 

Andarine, also referred to as S-40503, or S-4, is a selective androgen receptor modulator (SARM) originally developed for potential management of osteoporosis and muscle wasting. This non-steroidal compound is not approved for human use and is classified as prohibited in sport. No SARM is permitted as a dietary supplement ingredient under current standards.

SARMs are substances that bind to androgen receptors and activate selectively in tissues including muscle and bone. While early SARMs were steroidal, current use of the term centers on non-steroidal selective androgen receptor modulators, which are investigational drugs in regulatory review.

Tissue selectivity characterizes the intended mechanism of SARMs, which aim to promote anabolic activity in muscle and bone with reduced androgenic effects in other tissues such as the prostate and liver. Pharmaceutical development efforts continue for SARMs targeting muscle-wasting conditions and other medical indications.

To date, safety and efficacy data on SARMs remain insufficient. No SARM has received approval as a drug for human use. More than 40 SARMs remain in development as investigational new drugs, and some have appeared in the dietary supplement market contrary to their unapproved status.

Andarine has been listed on the World Anti-Doping Agency (WADA) Prohibited List since 2008 and remains banned in all athletic competition. The substance is included in section S1.2 as an "other anabolic agent" and is prohibited during and outside of competition.

Numerous athletes, including those in track and field, have tested positive for andarine since 2010. SARMs as a class now account for a significant proportion of anabolic agents detected in sport drug testing. The 2025 WADA Prohibited List names andarine and also includes other SARMs such as ostarine, LGD-4033, RAD140, S-23, and YK-11.

All SARMs are prohibited for athletes at every level of organized sport, based on their anabolic properties and the potential to provide an unfair performance advantage.

Marketing andarine or other SARMs as dietary supplement ingredients contradicts clear regulatory guidance. Such substances are not recognized as legal dietary supplement ingredients in the United States or most other jurisdictions.

In the U.S., andarine is permitted solely for research or medical-testing purposes. Some brands designate products as "for research use only" to circumvent regulation, but this designation does not remain valid if a product is capsulated, formulated for oral administration, or dosed for human consumption.

The U.S. Food and Drug Administration (FDA) considers inclusion of SARMs in dietary supplements as the sale of unapproved drugs. The agency has issued warning letters and has taken enforcement actions including investigations and prosecutions. For example, warning letters in December 2025 targeted companies marketing products identified as SARMs, including S-4.

Brands formulating or marketing SARMs as supplements for human consumption are subject to regulatory action regardless of labeling statements. The "research chemical" category does not exempt a product from regulation if it is prepared, labeled, or dosed for human use.

Adverse effects associated with andarine include vision impairment. Frequently reported symptoms include blurred vision, yellowish shade to vision, and vision flashes, particularly noticeable at night.

These symptoms result from the S-4 molecule binding to receptors in ocular tissue. Higher dosages and binding activity correlate with increased discomfort. At dosages of 50 mg per day or above, users report significant challenges adapting to changes in light. During clinical trials, the prevalence of visual side effects contributed to discontinuation of development for andarine.

Andarine has also demonstrated a tendency to suppress endogenous testosterone production to a greater extent than some other SARMs. Some users have reported depressive symptoms. Current data on SARMs and potential cancer risks remains insufficient and under investigation.

The FDA has issued statements that SARMs may cause life-threatening reactions, including liver toxicity, and may elevate the risk of heart attack or stroke. Lack of a therapeutic approval for SARMs means that comprehensive long-term safety data in humans is limited.

CROSS-CONTAMINATION RISKS DURING MANUFACTURING

SARMs present contamination risks in the dietary supplement industry, affecting manufacturing environments and supply chains. Facilities that produce SARM products may expose legitimate supplements to cross-contamination through shared equipment or inadequate protocols.

Some manufacturers, motivated by financial incentives, have produced SARMs in the same facilities as legal supplement products. Production may occur without sufficient segregation or cleaning of equipment and materials. Inadequate cleaning between runs can result in transfer of SARMs to subsequent batches of legitimate products.

Cross-contamination may also occur at the raw material stage, when suppliers handle both legal and prohibited substances. Documented cases exist in which an athlete tested positive after ingesting a supplement produced in a facility that also handled SARMs, despite those substances not appearing on the product label.

Analyses of the supplement market confirm measurable rates of contamination. A study in JAMA found that among 44 products marketed as SARMs, only 52% contained the stated SARM ingredients, while 25% included unlabeled substances. Another study published in BioMed Research International estimated that between 6.4% and 8.8% of reported doping cases result from undeclared ingredients in dietary supplements.

REGULATORY OVERSIGHT AND INTERNATIONAL ENFORCEMENT

The FDA has increased enforcement actions against manufacturers and distributors of SARMs, progressing from warning letters to investigations, felony convictions, prison sentences, and financial penalties.

Warning letters commonly reference violations for the marketing of unapproved drugs and misbranding of products as dietary supplements. FDA enforcement actions apply to all entities involved in formulating, producing, or distributing SARMs for human consumption.

Comparable regulatory positions have been adopted by international authorities. Most jurisdictions classify SARMs as unapproved drugs, which cannot be legally offered as dietary supplements. Supplement regulations vary, but SARMs’ investigational status consistently imposes barriers to their inclusion in consumer products.

Legislative and enforcement frameworks continue to adapt in response to the ongoing presence of SARMs in the market. While enforcement may serve as a deterrent, persistent financial incentives continue to drive illicit production.

Certification and Risk Mitigation

Third-party certification programs support verification that products are free from prohibited substances, including andarine and other SARMs, through testing, quality assurance, and compliance with manufacturing standards.

The BSCG Certified Drug Free program conducts banned substance screening for every finished product lot, testing for more than 450 drugs including over 400 substances prohibited by WADA. The program addresses the contamination risks that can arise through SARMs entering manufacturing or supply chains.

Certification programs that include SARMs in their banned substance panels allow brands to manage regulatory and reputational risk. These protocols also protect athletes, military personnel, and other individuals subject to drug testing. The process verifies the absence of andarine and related compounds, accounting for the potential of contamination from sources not directly controlled by the brand.

The Dietary Supplement Ingredient Advisory List identifies investigational ingredients and pharmaceutical-type substances that do not qualify for use in certified supplement products. Andarine and its designations, including S-40503, are listed under the SARMs category. No ingredient on this list is accepted in products under certification.

Certification protocols with transparent testing menus and clearly defined thresholds provide stakeholders with detailed information about substances screened and evaluation criteria. This transparency supports accountability and informed decision-making by quality and compliance teams.

Continued Vigilance in the Supplement Sector

ANDADRINE exemplifies persistent challenges associated with investigational drugs entering the dietary supplement market. The compound is prohibited in sport, not permitted as a supplement ingredient, and linked to specific health risks, including vision impairment and suppression of testosterone.

Manufacturing cross-contamination can expose brands that do not intentionally include SARMs to regulatory or reputational risk. Documented cases involving athletes support the necessity of robust testing and quality assurance protocols.

Regulatory agencies continue to address the illicit marketing of SARMs as supplements, but existing financial drivers contribute to ongoing occurrences. Quality and compliance personnel are advised to utilize comprehensive testing and certification programs that address the potential for both intentional adulteration and contamination.

Persistent circulation of SARMs in the supplement industry underscores the need for ongoing vigilance by manufacturers, brands, and regulatory agencies. Third-party certification and testing offer tools to support compliance and reduce risk to stakeholders governed by sport and regulatory standards.

Frequently Asked Questions (FAQ)

Legal Status of Andarine as a Dietary Supplement Ingredient

No SARM, including andarine, qualifies as a legal dietary supplement ingredient. The FDA and comparable regulatory agencies regard SARMs in supplements as unapproved drugs.

Banned Status of Andarine in Sport

Andarine has been on WADA's Prohibited List since 2008 and remains banned at all levels of athletic participation, applying both in and out of competition.

Risk of Contamination in Legitimate Supplements

Cross-contamination can occur in facilities or supply chains that handle both legitimate supplements and SARMs. Documented cases include athlete positives traced to contamination during manufacturing, absent ingredient disclosure.

Documented Health Risks Associated with Andarine

Reported health risks include vision impairment such as blurred or yellowish vision (especially at night), suppressed testosterone production, and possible mood effects. Prevalence of visual side effects contributed to abandonment in clinical development.

Process for Brands to Demonstrate Absence of Andarine

Brands can use third-party certification that includes comprehensive banned substance testing for each product lot to confirm the absence of andarine. Thorough protocols address the spectrum of SARMs and related compounds.

Claims about SARMs' Legal Status

Some companies incorrectly claim SARMs are legal by labeling products as "for research use only". This designation is not valid when products are prepared for human consumption or accompanied by usage instructions.

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