The main objective of this review is to highlight the therapeutic potential of allicin, a defense molecule in garlic known for its diverse health benefits, and address the key challenges of its bioavailability and stability. The research further aims to evaluate various formulation strategies and nanotechnology-based delivery systems that can resolve these issues and improve allicin's clinical efficacy, especially in cancer therapy. We conducted a comprehensive review of the available literature and previous studies, focusing on the therapeutic properties of allicin, its bioavailability, stability issues, and novel formulation strategies. We assessed the mechanism of action of allicin in cancer, including its effects on signaling pathways, cell cycle, apoptosis, autophagy, and tumor development. We also evaluated the outcomes of both in vitro and in vivo studies on different types of cancers, such as breast, cervical, colon, lung, and gastric cancer. Despite allicin's significant therapeutic benefits, including cardiovascular, antihypertensive, cholesterol-lowering, antimicrobial, antifungal, anticancer, and immune-modulatory activity, its clinical utility is limited due to poor stability and unpredictable bioavailability. Allicin's bioavailability in the gastrointestinal tract is dependent on the activity of the enzyme alliinase, and its stability can be affected by various conditions like gastric acid and intestinal enzyme proteases. Recent advances in formulation strategies and nanotechnology-based drug delivery systems show promise in addressing these challenges, potentially improving allicin's solubility, stability, and bioavailability. Allicin offers substantial potential for cancer therapy, yet its application is hindered by its instability and poor bioavailability. Novel formulation strategies and nanotechnology-based delivery systems can significantly overcome these limitations, enhancing the therapeutic efficacy of allicin. Future research should focus on refining these formulation strategies and delivery systems, ensuring the safety and efficacy of these new allicin formulations. Clinical trials and long-term studies should be carried out to determine the optimal dosage, assess potential side effects, and evaluate their real-world applicability. The comparative analysis of different drug delivery approaches and the development of targeted delivery systems can also provide further insight into enhancing the therapeutic potential of allicin.