This review critically evaluates the Life Cycle Assessment (LCA) of various hydrogen production pathways, focusing on their environmental impacts. The study analyzes the Global Warming Potential (GWP), Acidification Potential (AP), Abiotic Depletion Potential (ADP), and Human Toxicity (non-cancer) for different hydrogen production technologies. The main findings indicate that green hydrogen, produced via electrolysis powered by renewable energy, has the lowest environmental impact, with an average GWP of 2.02 kgCO₂eq/kgH₂. Pink hydrogen, produced via nuclear energy, has an even lower impact, with an average of 0.41 kgCO₂eq/kgH₂. In contrast, hydrogen produced using grid electricity (yellow hydrogen) has a significantly higher GWP, reaching up to 17.2 kgCO₂eq/kgH₂, with a peak of 41.4 kgCO₂eq/kgH₂ in countries with low renewable energy production. Waste pyrolysis and gasification have higher emissions than steam methane reforming, while the use of residual biomass and biowaste significantly reduces greenhouse gas emissions. The acidification potential is comparable across all technologies, except for biomass gasification, which shows higher and more scattered values. The abiotic depletion potential is mainly affected by the lack of recycling strategies, especially in electrolysis technologies. The study also highlights the importance of considering the entire life cycle of hydrogen production, including material recycling and end-of-life stages. The results show that the environmental impact of hydrogen production varies significantly depending on the production method, energy source, and system boundaries. The study concludes that green hydrogen is the most environmentally friendly option, followed by pink hydrogen, while other methods have higher environmental impacts. The findings emphasize the need for further research and development to improve the sustainability of hydrogen production technologies.This review critically evaluates the Life Cycle Assessment (LCA) of various hydrogen production pathways, focusing on their environmental impacts. The study analyzes the Global Warming Potential (GWP), Acidification Potential (AP), Abiotic Depletion Potential (ADP), and Human Toxicity (non-cancer) for different hydrogen production technologies. The main findings indicate that green hydrogen, produced via electrolysis powered by renewable energy, has the lowest environmental impact, with an average GWP of 2.02 kgCO₂eq/kgH₂. Pink hydrogen, produced via nuclear energy, has an even lower impact, with an average of 0.41 kgCO₂eq/kgH₂. In contrast, hydrogen produced using grid electricity (yellow hydrogen) has a significantly higher GWP, reaching up to 17.2 kgCO₂eq/kgH₂, with a peak of 41.4 kgCO₂eq/kgH₂ in countries with low renewable energy production. Waste pyrolysis and gasification have higher emissions than steam methane reforming, while the use of residual biomass and biowaste significantly reduces greenhouse gas emissions. The acidification potential is comparable across all technologies, except for biomass gasification, which shows higher and more scattered values. The abiotic depletion potential is mainly affected by the lack of recycling strategies, especially in electrolysis technologies. The study also highlights the importance of considering the entire life cycle of hydrogen production, including material recycling and end-of-life stages. The results show that the environmental impact of hydrogen production varies significantly depending on the production method, energy source, and system boundaries. The study concludes that green hydrogen is the most environmentally friendly option, followed by pink hydrogen, while other methods have higher environmental impacts. The findings emphasize the need for further research and development to improve the sustainability of hydrogen production technologies.