This thesis seeks to demonstrate why investment protection of patented health resources is disproportionate and how the disproportionate power can be mitigated. The argument asserts that the protection of patented health resources under international investment agreements (“IIAs”) goes beyond the intended purpose of intellectual property (“IP”) law and can hinder access to health resources. While IP rights are significant components of IIAs, their inclusion within the scope of investment allows investors to challenge measures against their IP rights through the investor-state dispute mechanism (“ISDS”). A measure can be subject to a review of arbitral tribunals even though such measure serves the public interest. The ISDS system imposes an additional legal layer for states. Such layer can hinder the rights to have a healthy life, rights to life and living a life with dignity, conflicting states’ human rights obligations. Therefore, this thesis argues that investment protection disproportionately benefits the patent holders. Consequently, this thesis scrutinises how this disproportionate benefit can be mitigated. To this end, this thesis investigates case law in investment arbitration where arbitral tribunals have applied (ii)judicial proportionality to determine if judicial proportionality can mitigate the disproportionate protection of patented health resources as an investment. This thesis further reveals midlevel proportionality in newly concluded IIAs where the purpose is to restore disproportionate investment protection of patented health resources. This thesis presents the first comprehensive analysis on proportionality principle in the context of patent and international investment law.