The evidence
Each criterion with what we found, where we found it and when. Anything we could not confirm says so.
NTH criteria
NTH Framework v1.2. Score 74.1 (raw 56.0 of 100), calibrated so the best hotel in this edition (Santa Monica Proper Hotel) reads 90. Evidence retrieved 2026-10-22.
Sleep12.0 / 24
The room as an instrument for deep, uninterrupted, circadian-aligned rest.
Mattress & sleep system
Hotel-reported · in the best room
Handmade natural mattresses (organic wool, coir, organic latex).
Bedding & textiles
Hotel-reported · in the best room
Organic cotton sheets; temperature-regulating pillows and duvets.
Sleep programme & pillow menu
Hotel-reported · in the best room
Sleep programme: tracker data, consultation, yoga nidra.
Blackout
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Circadian & warm evening lighting
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
In-room red light
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Acoustic quiet
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 4 pts
Unknown
EMF & Wi-Fi-off options
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Air2.0 / 12
What you breathe for eight hours a night: filtered, fresh, smoke-free and unperfumed.
In-room purification
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 5 pts
Unknown
Ventilation & building standard
Hotel-reported · across the property
First BREEAM-certified resort in the Balearics.
Smoke-free policy
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Fragrance-free & low-allergen rooms
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Water3.0 / 12
Clean water to drink, and to shower and bathe in.
Filtered drinking water
Hotel-reported · in the best room
Filters and bottles its own water.
Shower & bath filtration
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 5 pts
Unknown
Gentler pool & hydrotherapy water
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 2 pts
Unknown
Nourishment7.0 / 10
Food and drink that heal rather than merely please.
Organic & local sourcing
Hotel-reported · across the property
Organic, seasonal; organic gardens; farm-to-table.
Clean-ingredient standard
Not yet reviewed · across the property
Unknown. We have asked the hotel.
0.0 / 3 pts
Unknown
Clean minibar & in-room hydration
Hotel-reported · in the best room
House-filtered water; single-use plastics eliminated.
Nutrition guidance
Hotel-reported · across the property
Nutrition guidance in programmes.
Movement9.0 / 10
The means to train, stretch and move, indoors and out.
Gym completeness
Hotel-reported · across the property
24/7 gym, high-intensity room, outdoor boxing ring; brands not named.
Classes & studios
Hotel-reported · across the property
Indoor yoga studio, rooftop and seafront yoga; classes.
Swimming
Hotel-reported · across the property
Infinity pool and lap pools.
Outdoor activity
Hotel-reported · across the property
Hiking, bike tours, outdoor bootcamps.
Holistic Wellness16.0 / 19
Healing traditions and the recovery technology that complements them.
Spa facility
Hotel-reported · across the property
1,200 sq m spa, five treatment rooms, hammam, steam.
Traditional & integrative modalities
Hotel-reported · across the property
Functional medicine (RoseBar); energy treatments.
Mind & breath
Hotel-reported · across the property
Meditation, sound healing, breathwork.
Heat therapy
Hotel-reported · across the property
Infrared sauna.
Cold therapy
Hotel-reported · across the property
Cryotherapy.
Photobiomodulation & PEMF
Hotel-reported · across the property
Red-light therapy.
Clinical longevity (IV, HBOT, diagnostics)
Hotel-reported · across the property
Diagnostics, HBOT, hypoxic training.
Materials & Setting7.0 / 13
What touches the skin and surrounds the stay: finishes, products, cleaning, and the landscape beyond the door.
Natural, low-VOC finishes
Not yet reviewed · in the best room
Unknown. We have asked the hotel.
0.0 / 3 pts
Unknown
Clean bath & body amenities
Hotel-reported · in the best room
Sustainable bathroom amenities.
Non-toxic spa & nail products
Hotel-reported · across the property
Spa botanicals grown in the organic gardens.
Non-toxic housekeeping & plastic-free operations
Hotel-reported · across the property
Single-use plastics eliminated.
Green & blue space
Hotel-reported · across the property
On Xarraca Bay; maritime forest.
Walkability & low-impact mobility
Hotel-reported · across the property
Bike tours.
Our review
At a glance
- Fragrance
- 5 not yet reviewed
- Air
- 5 not yet reviewed
- Cleaning & care
- 4 not yet reviewed
- Sleep & materials
- 5 not yet reviewed
- Water & pools
- 1 hotel-reported, 3 not yet reviewed
- Food
- 1 hotel-reported, 1 not yet reviewed
- Light & quiet
- 2 not yet reviewed
- Building
- 1 hotel-reported, 2 not yet reviewed
Nothing reviewed yet: every criterion is shown as not yet reviewed.
Nothing reviewed yet25 of 25 not yet reviewed
Counts cover the 25 scored criteria; the other 5 windows are context.
Checked
Read the full profileThe ledger
Fragrance
Added scent is the most common complaint from sensitive guests, and the hardest thing to see on a booking page.
No added fragrance in rooms
Not yet reviewed.
No scent marketing
Not yet reviewed.
Fragrance-free laundry
Not yet reviewed.
Unscented bath products
Not yet reviewed.
So far, the hotel says: Rooms list ‘sustainable bathroom amenities’.
Our note. Whether they are fragrance-free, or available unscented on request, is not stated.
How we know
What we look for. Fragrance-free toiletries in the room by default, or on request.
Why it matters. Fragrance ingredients are among the most frequent causes of allergic contact reactions to cosmetics. An unscented option lets sensitive guests use what is provided instead of packing their own.
Source: EU Scientific Committee on Consumer Safety, Opinion on fragrance allergens in cosmetic products ()
Source 1: Hotel website: accommodationUndated · read 22 Oct 2026
Unscented spa options
Not yet reviewed.
So far, the hotel says: The spa has a steam room, hammam, sauna and treatment rooms, with botanicals grown in the organic gardens for the spa and its Alchemy Bar.
Our note. Whether treatments, sauna and steam can be had without scent is not stated.
How we know
What we look for. Treatments, saunas and steam rooms available without essential oils or scent infusions.
Why it matters. Essential oils are fragrance: the EU’s scientific committee lists several natural extracts, as well as single fragrance chemicals, among established contact allergens. A shared sauna with a scent infusion is hard to avoid.
Source: EU Scientific Committee on Consumer Safety, Opinion on fragrance allergens in cosmetic products ()
Source 2: Hotel website: wellness and spaUndated · read 22 Oct 2026
Know something about fragrance here that we don’t? Tell us
Air
What you breathe for eight hours a night: smoke history, fresh air, filtration and anything burning in the room.
Smoke-free property
Not yet reviewed.
Opening windows
Not yet reviewed.
Filtered fresh air
Not yet reviewed.
In-room air purifier
Not yet reviewed.
No in-room combustion
Not yet reviewed.
Know something about air here that we don’t? Tell us
Cleaning & care
How a room is cleaned, treated and prepared, and whether a request for a gentler clean is actually honored.
Low-chemical housekeeping
Not yet reviewed.
No ozone or biocide treatments
Not yet reviewed.
Low-chemical pest control
Not yet reviewed.
Sensitive-guest preparation
Not yet reviewed.
Know something about cleaning & care here that we don’t? Tell us
Sleep & materials
The textiles, mattress and floor you spend the night closest to, and how allergen-aware the room is.
Tested or organic bed linen
Not yet reviewed.
So far, the hotel says: The rooms page lists ‘organic cotton sheets’ among the Sleep With Six Senses tools.
Our note. No certification, such as GOTS or OEKO-TEX, is named, so this falls short of the criterion.
How we know
What we look for. Sheets and towels certified to a residue-testing standard such as OEKO-TEX Standard 100, or certified organic.
Why it matters. Certifications such as OEKO-TEX Standard 100 test the finished fabric, down to the thread, against a list of restricted substances, which lowers skin exposure over a night’s sleep.
Source: OEKO-TEX, OEKO-TEX Standard 100 (undated)
Source 1: Hotel website: accommodationUndated · read 22 Oct 2026
Mattress materials disclosed
Not yet reviewed.
So far, the operator says: The handmade mattress is ‘made from organic lamb’s wool with coir fiber’ and a latex layer from a certified organic rubber plantation.
Our note. This is the brand’s description, linked from the Ibiza rooms page. How flame-retardancy is achieved is not stated, so this falls short of the criterion.
How we know
What we look for. The hotel says what its mattresses are made of and how flame-retardancy is achieved.
Why it matters. Flame retardants have been added to mattresses and seating foam, and the US National Institute of Environmental Health Sciences lists possible effects including endocrine and thyroid disruption. How much a mattress adds to anyone’s exposure is still debated; disclosure lets guests choose.
Source: US National Institute of Environmental Health Sciences, Flame retardants (undated)
Source 3: Six Senses: Sleep With Six SensesUndated · read 22 Oct 2026
Hard floors
Not yet reviewed.
Allergy-friendly rooms
Not yet reviewed.
So far, the operator says: The mattress cover is described as anti-mite and hypoallergenic, and the organic pillows and duvets as non-allergenic and resistant to mites.
Our note. Pillow barrier covers and hot-washable bedding are not described, so this falls short of the criterion.
How we know
What we look for. Allergen-barrier mattress and pillow covers and feather-free, hot-washable bedding, in all or designated rooms.
Why it matters. For dust-mite allergy, US health guidance is to encase mattresses and pillows in allergen-proof covers and wash bedding weekly in hot water (130–140 °F, about 55–60 °C).
Source: US National Institute of Environmental Health Sciences, Dust mites and cockroaches (undated)
Source 3: Six Senses: Sleep With Six SensesUndated · read 22 Oct 2026
Pet-free rooms
Not yet reviewed.
Know something about sleep & materials here that we don’t? Tell us
Water & pools
Drinking water, shower water and pool air.
Filtered or tested drinking water
Not yet reviewed.
So far, the hotel says: The resort describes ‘filtering and bottling our own water’, and rooms list Six Senses bottled drinking water.
Our note. The filtration method and any testing or filter-change schedule are not stated, so this falls short of the criterion.
How we know
What we look for. Drinking water filtered at the tap or refill station, or treated and tested on site, with filters or tests on a schedule.
Why it matters. Public water systems in California are regulated and monitored by the State Water Board, though older building plumbing can still affect what reaches the tap. Filtration mainly improves taste and removes chlorine, and it replaces single-use bottles; private wells need regular testing.
Source: California State Water Resources Control Board, Division of Drinking Water (undated)
Source 4: Hotel factsheet (PDF)Undated · read 22 Oct 2026
Water safety plan
Not yet reviewed.
Shower filters
Not yet reviewed.
Shown for information; not scored.
Outdoor or low-chloramine pools
Hotel-reportedonly some rooms or areas
The hotel says: The main infinity pool overlooks Xarraca Bay and is reached directly from the terraces of the Pool Level suites; there are also two lap pools.
Our note. How the pools are sanitised is not stated. The spa’s caldarium and hammam sit inside the cliffside; their ventilation is not described.
Shown for information; not scored.
How we know
What we look for. Pools are outdoors, or indoor pools have dedicated ventilation and monitored combined chlorine.
Why it matters. Chloramines irritate the skin, eyes and airways, and they build up in the air of indoor pools without enough ventilation. Outdoor pools, and good ventilation for indoor ones, keep levels low.
Source: US CDC, Chloramines and pool operation ()
Source 1: Hotel website: accommodationUndated · read 22 Oct 2026
Context, not scored: almost every pool in this catalog is outdoors, so it says little about one hotel against another.
Know something about water & pools here that we don’t? Tell us
Food
Allergen care first; where the produce comes from second.
Allergen-aware kitchen
Not yet reviewed.
Garden or organic produce
Hotel-reportedacross the property
The hotel says: The resort grows ‘healthy, organic produce on our nearby farm, Can Tanca, delivering fresh fruit and vegetables every day’.
Our note. The farm is off site; the factsheet places it near Santa Gertrudis. Organic is the resort’s own word; it names no certifier, and the share of the kitchen’s produce is not given.
Shown for information; not scored.
How we know
What we look for. A meaningful share of the kitchen’s produce is grown on site or certified organic.
Why it matters. A large review found detectable pesticide residues about four times as often in conventional crops as in organic ones. Over a short stay the difference in exposure is small, so we show this as a note on the kitchen, not a scored health factor.
Source: Barański et al., British Journal of Nutrition, Higher antioxidant and lower cadmium concentrations and lower incidence of pesticide residues in organically grown crops: a systematic literature review and meta-analyses ()
Source 5: Hotel website: sustainabilityUndated · read 22 Oct 2026
Kitchen note, not scored.
Know something about food here that we don’t? Tell us
Light & quiet
Darkness and silence at night, and radio-quiet options for guests who want them.
Darkness and quiet
Not yet reviewed.
Radio-quiet options
Not yet reviewed.
So far, the hotel says: Rooms list Wi-Fi among their amenities.
Our note. Whether it can be switched off in the room is not stated.
Shown for information; not scored.
How we know
What we look for. Wi-Fi that can be switched off in the room, or a wired connection. Listed as an amenity only.
Why it matters. Some guests prefer lower radio exposure. The WHO says current evidence does not confirm any health effects from low-level electromagnetic fields, so we list these options as amenities, not as health benefits.
Source: World Health Organization, Radiation: electromagnetic fields ()
Source 1: Hotel website: accommodationUndated · read 22 Oct 2026
Not part of any health score. Shown as an amenity at the guest’s preference.
Know something about light & quiet here that we don’t? Tell us
Building
The materials a hotel was built and renovated with, how it handles damp, and what third parties have certified.
Low-emitting materials
Not yet reviewed.
Leak and mold response
Not yet reviewed.
Building certification
Hotel-reportedacross the property
The hotel says: It is ‘the first BREEAM certified resort’ in the Balearics, and also holds ISO 9001 and ISO 14001.
Our note. BREEAM is an environmental assessment, not a health one. No rating or year is given, and we have not checked the BREEAM register.
Shown for information; not scored.
How we know
What we look for. A third-party certification such as WELL, LEED or a green business program, recorded with its level, and its year where the certifier gives one.
Why it matters. WELL assesses air, water and light in occupied buildings. LEED and green business programs are mainly environmental, with some indoor-quality elements. A certificate records what was designed or checked at a point in time, not what a room is like today.
Source 5: Hotel website: sustainabilityUndated · read 22 Oct 2026
Context only. A certificate supports specific criteria only where its scope covers them.
Know something about building here that we don’t? Tell us
Notes & sources
- Hotel website: accommodation, Undated · read 22 Oct 2026
- Hotel website: wellness and spa, Undated · read 22 Oct 2026
- Six Senses: Sleep With Six Senses, Undated · read 22 Oct 2026
- Hotel factsheet (PDF), Undated · read 22 Oct 2026
- Hotel website: sustainability, Undated · read 22 Oct 2026
- RoseBar: longevity clinic at Six Senses Ibiza, Undated · read 22 Oct 2026
- RoseBar: Red Light Therapy, 4 Sept 2025 · read 22 Oct 2026
Room count: Per the hotel’s factsheet: 137 accommodations, including residences and two mansions. Hotel website (opens the hotel’s website)
Photographs: Six Senses Ibiza; Six Senses Ibiza; Six Senses Ibiza; Six Senses Ibiza; Six Senses Ibiza; Six Senses Ibiza; Six Senses Ibiza
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