There are not even drugs known to specifically help DPDR though some people benefit from psych meds, neuroleptics, blood pressure meds, etc. This is widely thought to treat an underlying condition causing or caused by the depersonalization.
Selling supplements is a big market. They'll sell you capsules of concentrated, dehydrated cranberries for $20 to $60 per bottle. You're probably deficient in several vitamins because, you know, few people can afford to have a perfect diet. Magnesium is a nutrient in food. 5HTP is a product your body makes from an essential amino acid called tryptophan. Amino acids are broken down from proteins in your diet. Essential more or less means you must eat this amino acid to be healthy. I'm not a biologist or chemist but basically 5HTP is converted to serotonin.
Lack of physical activity can worsen nutritional health because we either end up eating less food, thus consuming less nutrients, or becoming overweight. Processed foods also contribute to poor nutritional health especially if they're not enriched. Basically modern lifestyles especially in rural and suburban North America are antithetical to physical wellbeing unless you go out of your way to exercise which most people don't. That's not even getting started on emotional wellbeing.