Table 2.

Positive and negative effects of NAM shown in human studies ¹.

Affected Organs and Conditions 2	Observed Effects	Dose and Duration	References
Beneficial effects
Joints	Reduced itching in uremic patients	550 mg twice a day (4 weeks)	[38]
pancreatic β-cell	β-cell function preserved and improved	25 mg/kg daily intake (4 weeks)	[18,39]
	Reduced the rate of diabetes incidence	500 mg twice per day (2.5 years)	[19]
	No effect on the incidence of being diabetes-free	1200 mg daily intake (5 years)	[20]
	Ineffective in prevention or delaying clinical onset of diabetes	1.2 g daily intake (3 years)	[21]
Skin	Reduced acne lesions and severity	4% gel applied twice daily (8 weeks)	[26]
	Attenuated immunosuppression with alterations in metabolism and apoptosis	5% lotion applied before UV exposure	[40]
Psychology	Improvements against depression	0.5–1.5 g daily intake (3 weeks)	[22]
	Relief from anxiety	A dose of 2 ug 3 h prior to test	[23]
Kidney	Lowered serum concentrations of phosphorus, parathyroid hormone, and LDL, and increased serum HDL	500 mg/day (with and increment every 2 weeks) (12 weeks)	[41]
Skin cancers non-melanoma	Reduced incidence of various types of skin cancers and actinic keratoses	500 mg twice daily (4 months)	[42]
Adverse Effects
Minor effects	Frontal dull headaches, nausea, headache, dizziness	1–18 g immediate	[43,44]
Pancreatic β-cell/plasma	Decreased insulin sensitivity, increased oxidative stress (H2O2)	2 g daily (2 weeks)	[45,46]
Liver	Parenchymal-cell injury, portal fibrosis and cholestasis, liver injury	3, 9 g daily (10 days)	[47]
Lymphocytes, platelets	Uremic toxicity-related cancer and thrombocytopenia	1300, 1500 mg daily (24 weeks)	[48]
Kidney/platelets	Decreased serum phosphorus and thrombocytopenia	0.52–2 g daily (3–6 months)	[49,50]

¹ Some examples of human studies are presented. For more information on the beneficiary effects, check Reference [27]. ² In all human applications except for skin, NAM was administered through dietary intake.