No—“20 mg daily for four weeks” is not an established safe limit for bodybuilding. Staying below either figure does not guarantee safety.
Halotestin (fluoxymesterone) is a 17-alpha-alkylated oral androgen. Its prescribing information warns about liver injury, including cholestatic hepatitis and jaundice, and potentially life-threatening liver complications associated with prolonged high-dose use. It explicitly states that the drug has not been shown to be safe and effective for enhancing athletic performance. Halotestin® CIII fluoxymesterone tablets, USP
Medical dosing and treatment duration depend on the condition being treated and clinical monitoring; they should not be converted into a bodybuilding cycle. Liver-support supplements also cannot establish a safe dose or duration.
If you’re already using it, speak with a clinician rather than waiting until the fourth week to review it. Yellow eyes or skin, dark urine, severe itching or abdominal pain warrant prompt medical attention.
Source: Halotestin prescribing information.