Yamate Onsen No. 3 is a simple thermal spring classified as hot (45.1 °C), neutral, and hypotonic. Mineralization is light at around 412 mg/kg, but the water carries a generous 105 mg/kg of metasilicic acid, leaving the kind of thin silica film that makes skin feel noticeably smoother afterwards. At the wellhead it presents as practically colorless, tasteless, and odorless — a gentle, low-stimulation entry in Beppu's hot-source roster.
Good for
Aches & joints
Warmth eases stiffness and raises the pain threshold. Radon and sulfate springs show the strongest evidence for joint and muscle pain.
stiff shoulders
Smooth skin
Bicarbonate and alkalinity gently lift dead keratin while silica hydrates, leaving skin smooth. This is the basis of the beautifying-water (bijin-no-yu 美人の湯) reputation.
dry, rough skin
Recovery
Warmth and buoyancy lower stress markers and improve sleep; habitual bathing is linked to lower rates of depression.
fatigue, stress
Take care
- 病気の活動期(特に熱のあるとき)
- 活動性の結核、進行性の悪性腫瘍又は高度の貧血など身体衰弱の著しい場合
- 少し動くと息切れがするような重い心臓又は肺の病気のあるとき
- むくみのあるような重い腎臓の病気、消化管出血、目に見える出血があるとき
- 慢性の病気の急性増悪期
Full composition
The bar is each ion's share of charge (mval%) within its group; over 20% names the spring. Gases, silica and trace metals are measured by mass only.
- Sodiumsalt's cation — pairs with chloride to make the water saltyNa⁺82.0mgP25 national73%
- Calciumsettling and calming; can leave a white mineral bloomCa²⁺14.5mgP31 national15%
- Potassiumminor; matters for drinking limitsK⁺9.5mgP44 national5%
- Magnesiummild; a laxative if you drink itMg²⁺3.5mgP41 national5%
- LithiumLi⁺0.50mgP55 national1%
- Aluminumshows up in acidic volcanic waterAl³⁺0.06mgP31 national1%
- AmmoniumNH₄⁺0.10mgP24 national0.2%
- StrontiumSr²⁺0.10mgP26 national0.1%
- Iron (II)rusts brown in air; iron for anemia when drinkableFe²⁺< —mg
- Chloridetable-salt anion — coats the skin and holds heat inCl⁻104mgP41 national64%
- Sulfate"gypsum / Glauber's salt" — vessels and wound healingSO₄²⁻43.7mgP38 national20%
- Bicarbonate"soda" — softens skin, leaves it smoothHCO₃⁻43.4mgP25 national16%
- FluorideF⁻0.20mgP17 national0.2%
- NitrateNO₃⁻1.7mgP89 national0.2%
- BromideBr⁻0.30mgP36 national0.1%
- Metasilicic acidmetasilicic acid — a natural moisturizer for silky skinH₂SiO₃105mgP56 national
- Metaboric acidmetaboric acid — mildly antibacterialHBO₂3.5mgP27 national
- Phosphoric acidH₃PO₄0.10mgP97 national
- Free carbon dioxidefizz — widens blood vessels (strong above 1000 mg/kg)CO₂40.0mgP65 national
- LeadPb0.10mgP98 national
- ArsenicAs< —mg
- CadmiumCd< —mg
- CopperCu< —mg
Measured at the source
On the certificate
- 筋肉若しくは関節の慢性的な痛み又はこわばり(関節リウマチ、変形性関節症、腰痛症、神経痛、五十肩、打撲、捻挫などの慢性期)、運動麻痺における筋肉のこわばり、冷え性、病後回復期、疲労回復、健康増進、胃腸機能の低下(胃もたれ、腸にガスがたまるなど)、軽症高血圧、耐糖能異常(糖尿病)、軽い高コレステロール血症、軽い喘息又は肺気腫、痔の痛み、自律神経不安定症(睡眠障害、うつ状態など)、ストレスによる諸症状、健康増進
- 高齢者における身体衛生
- 自律神経不安定症、不眠症、うつ状態
Evidence
- Maeda M. 温泉の医学的効果とその科学的根拠. J. Hot Spring Science 70:197–207, 2021.
- Naito Y et al. A Hot-Spring Water Improves Inflammatory Conditions in an Atopic Dermatitis Model. Biomedicines 13(11):2707, 2025.
- Donaubauer AJ et al. Serial radon spa therapy on pain in musculoskeletal disorders. Frontiers in Immunology, 2024.
- Verhagen AP et al. Balneotherapy for rheumatoid arthritis. Cochrane Database of Systematic Reviews CD000518, 2015.
- Li H et al. Bicarbonate Ionized Water Bathing Enhances Natural Killer Cell Activity. Scientific Reports 14:51851, 2024.
- Takeda M et al. Hot spring bathing practices have a positive effect on mental health in Japan. Heliyon 9(9):e19631, 2023.