**Background:** Beetroot (Beta vulgaris L.) is rich in bioactive substances including betalain pigments, phenolic compounds, and inorganic nitrates and nitrites, which may confer health benefits such as improved endothelial function, blood pressure regulation, and athletic performance. However, excessive nitrate intake poses risks including methemoglobinemia and N-nitrosamine formation. Despite the growing popularity of beetroot-based dietary supplements (DSs), research on their quality, safety, and comparative value relative to fresh beetroot is limited. This study aimed to assess the quality and safety of 50 beetroot-based DSs compared to 20 fresh beetroot samples.
**Methods:** Fifty DSs (tablets, capsules, powders) and 20 beetroot samples (divided into peeled, unpeeled, and skins subgroups) were analyzed. Total phenolic content (TPC) was determined using the Folin-Ciocalteu (FC) method. Total antioxidant capacity (TAC) was assessed using CUPRAC and DPPH assays. Nitrite and nitrate quantification was performed by spectrophotometry using Griess reagents according to ISO 6635-1984. Extraction was optimized using two-stage ultrasound-assisted extraction with 50% MeOH + 0.1% FA. Health risk was assessed by calculating the percentage of acceptable daily intake (ADI) realized for nitrites (ADI = 0–0.2 mg/kg b.w. NO₂⁻) and nitrates (ADI = 0–5 mg/kg b.w. NO₃⁻). Labeling compliance was evaluated against Regulation (EU) No 1169/2011 and Polish national regulations. Statistical analyses included ANOVA Kruskal-Wallis, U Mann-Whitney, and Spearman's rank correlation.
**Key Results:** Fresh beetroot (100 g) provided significantly more antioxidants, nitrites, and nitrates than most DS daily doses. For TPC, powders showed the highest values among DSs (up to 251 mg GAE/d.d. for product P9), but lyophilizates exceeded all DS groups. For TAC (CUPRAC), product P9 reached 3520 μmol TE/d.d., higher than average beetroots. Nitrite levels in DSs ranged from 0.21–78 µg/d.d., and nitrate levels from 0.197–169 mg/d.d. Only three products—P9 (169 mg/d.d., 48% ADI for NO₃⁻), P10 (99 mg/d.d., 28% ADI), and P13 (131 mg/d.d., 37% ADI)—delivered higher nitrate doses than fresh beetroot (90 mg/100 g f.w. conventional, 15–20.1% ADI). No product exceeded the ADI for nitrites (0.0015–0.55% ADI) or nitrates (0.056–48% ADI). Four DSs declared nitrate content on labels; two (C10, C11) contained no detectable nitrates despite declarations, one (C1) contained only 4.2% of declared value, and one (P9) contained 85% of declared value. Labeling assessment revealed that 64% of packaging failed to meet legal requirements, 12% were not registered with the Chief Sanitary Inspectorate, 21% contained prohibited or unregistered health claims, and 15% suggested disease-preventing or treating properties. A statistically significant negative correlation was found between antioxidant potential (FC and CUPRAC) and nitrate content in beetroot samples (Spearman's r = −0.54 for FC, −0.62 for CUPRAC), but not in DSs.
**Clinical Implications:** The study demonstrates that most beetroot-based DSs provide negligible antioxidant and nitrate doses compared to fresh beetroot, suggesting low health value for consumers. Only three powder products approached or exceeded the nitrate content of a standard beetroot serving. None of the tested products posed a risk of exceeding the ADI for nitrites or nitrates when used as directed. However, the widespread labeling deficiencies—including missing Polish-language information, unclear dosing instructions, and illegal health claims—pose risks of consumer misinformation, potential overdose, and abandonment of conventional therapies. The authors conclude that tighter regulatory control over DS composition and labeling is needed, as current enforcement by national and European authorities appears insufficient.