A computer-implemented method for non-invasive quantification of metabolites in a body, comprising: a) predicting (S520; S8020) aleotoric uncertainty information and a sample spectrum from a pre-processed input spectrum using an artificial neural network; b) generating a predictive mean spectrum by calculating an average of the sample spectrum; c) calculating (S560, S8040) an epistemic uncertainty spectrum of the sample spectrum based on a variance of the sample spectrum; d) calculating (S570, S8050) an aleatoric uncertainty spectrum of the sample spectrum based on an average of the aleatoric uncertainty information; e) calculating (S590, S8060) a two-standard deviation, 2SD, spectrum of the sample spectrum based on the epistemic uncertainty spectrum and the aleatoric uncertainty spectrum; f1) performing baseline correction on the predictive mean spectrum and the 2SD spectrum; f2) calculating a metabolite content value by performing linear regression on the corrected predictive mean spectrum; f3) calculating a metabolite standard deviation value by performing linear regression on the corrected 2SD spectrum; and f4) normalizing the metabolite content value and the metabolite standard deviation value; g) wherein the normalizing is based on a relative content of the metabolite to water or a relative content of the metabolite to a reference metabolite; h) wherein the relative content of the metabolite to the water is calculated based on Equation 1, Conc meta = 55 ∗ S meta S water ∗ CorrTiss ∗ Nspins water Nspins meta, where the Conc meta denotes a content of a target metabolite (mmol/L), the S meta denotes a signal area of the target metabolite, the S water denotes a signal area of the water, the CorrTiss denotes a ratio of water in a biological tissue from which a magnetic resonance spectroscopy signal is obtained, the Nspins water denotes the number of spins of water participating in generating a resonance signal, and the Nspins meta denotes the number of spins of the target metabolite participating in generating the resonance signal. a) predicting (S520; S8020) aleotoric uncertainty information and a sample spectrum from a pre-processed input spectrum using an artificial neural network; b) generating a predictive mean spectrum by calculating an average of the sample spectrum; c) calculating (S560, S8040) an epistemic uncertainty spectrum of the sample spectrum based on a variance of the sample spectrum; d) calculating (S570, S8050) an aleatoric uncertainty spectrum of the sample spectrum based on an average of the aleatoric uncertainty information; e) calculating (S590, S8060) a two-standard deviation, 2SD, spectrum of the sample spectrum based on the epistemic uncertainty spectrum and the aleatoric uncertainty spectrum; f1) performing baseline correction on the predictive mean spectrum and the 2SD spectrum; f2) calculating a metabolite content value by performing linear regression on the corrected predictive mean spectrum; f3) calculating a metabolite standard deviation value by performing linear regression on the corrected 2SD spectrum; and f4) normalizing the metabolite content value and the metabolite standard deviation value; g) wherein the normalizing is based on a relative content of the metabolite to water or a relative content of the metabolite to a reference metabolite; h) wherein the relative content of the metabolite to the water is calculated based on Equation 1, Conc meta = 55 ∗ S meta S water ∗ CorrTiss ∗ Nspins water Nspins meta, where the Conc meta denotes a content of a target metabolite (mmol/L), the S meta denotes a signal area of the target metabolite, the S water denotes a signal area of the water, the CorrTiss denotes a ratio of water in a biological tissue from which a magnetic resonance spectroscopy signal is obtained, the Nspins water denotes the number of spins of water participating in generating a resonance signal, and the Nspins meta denotes the number of spins of the target metabolite participating in generating the resonance signal. the S meta denotes a signal area of the target metabolite, the S water denotes a signal area of the water, the CorrTiss denotes a ratio of water in a biological tissue from which a magnetic resonance spectroscopy signal is obtained, the Nspins water denotes the number of spins of water participating in generating a resonance signal, and the Nspins meta denotes the number of spins of the target metabolite participating in generating the resonance signal.